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Physical Properties of Polymers Under Soft and Hard Nanoconfinement: A Review
Ming-Chao Ma, Yun-Long Guo
Corrected proof , doi: 10.1007/s10118-020-2380-3
[Abstract](81) [FullText HTML](8) [PDF 613KB](14)
Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk, especially glass transition temperature, physical aging, and crystallization behavior. Here we highlight the leading methods for creating various confinement systems. Upon these systems, recent advances on hard and soft confinement effect for glass transition, physical aging, mechanical properties and crystallization of polymers are reviewed in details. Furthermore, as nanoconfined systems in extreme conditions are experimentally inaccessible, simulation results describing confinement effect on such systems are also discussed.
Tunable Cis-cisoid Helical Conformation of Poly(3,5-disubstibuted phenylacetylene)s Stabilized by nπ* Interaction
Sheng Wang, Si-Liang Cai, Jie Zhang, Xin-Hua Wan
Corrected proof , doi: 10.1007/s10118-020-2376-z
[Abstract](146) [FullText HTML](9) [PDF 619KB](10)
A series of novel cis poly(phenylacetylene)s (PPAs) substituted at meta-position(s) by two alkoxycarbonyl pendants, i.e., sP-Me-C8/rP-Me-C8 , P-Me-C12 , sP-Et-C4 , sP-2C4 and sP-Oct-C4 , were synthesized under the catalysis of [Rh(nbd)Cl]2 (nbd = norbornadiene). The dependence of elongation, screw sense, and stimuli response of helical polyene backbone on the structure of pendant, solvent, and temperature was systematically investigated in both solution and solid states. Because of nπ* interaction between vicinal carbonyl groups, sP-Me-C8/rP-Me-C8 could adopt contracted cis-cisoid helix in THF, toluene, CH2Cl2, and CHCl3. Such an intramolecular interaction was sensitive to the hydrogen bond donating ability of solvent and temperature, but insensitive to the dielectric constant and polarity of solvent. In poly(3-methoxycarbonyl-5-alkoxycarbonylphenylacetylene), the longer the chiral alkyl chain was, the easier the stable cis-cisoid helix could be achieved. However, when the methoxycarbonyl was changed to ethoxycarbonyl, sec-butyloxycarbonyl, and octyloxycarbonyl pendant groups, only cis-transoid helix was obtained at room temperature due to the increased steric hindrance. Moreover, lowering temperature was found to facilitate the stabilization of nπ* interactions, and reversible temperature-dependent stereomutations were achieved in sP-Me-C8 and sP-Et-C4 depending on the solvent where they were dissolved. These results suggested that the long alkyl chain, small pendant size, and lower temperature favored the stabilization of intramolecular nπ* interactions and the formation of contracted, cis-cisoid helices for poly(3,5-diester substituted phenylacetylene)s.
Highly Soluble Polyimides Containing Di-tert-butylbenzene and Dimethyl Groups with Good Gas Separation Properties and Optical Transparency
Chen-Yi Wang, Cai-Rong Jiang, Bin Yu, Xiao-Yan Zhao, Zhao-Liang Cui, Jian Li, Qiang Ren
Corrected proof , doi: 10.1007/s10118-020-2377-y
[Abstract](47) [FullText HTML](6) [PDF 609KB](3)
A rigid aromatic diamine monomer containing di-tert-butylbenzene and dimethyl groups, 3,3′-dimethyl-4,4′-diaminophenyl- 3″,5″-di-tert-butyltoluene, was successfully synthesized by a simple coupling reaction using 3,5-di-tert-butylbenzaldehyde and o-toluidine as starting materials. A series of novel polyimides ( PI 3a3c ) with large pendant groups were prepared with the obtained diamine monomer and three different commercial aromatic dianhydrides (3,3′,4,4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride) by one-step high temperature polycondensation. The prepared polyimides exhibited high solubility and good membrane forming ability: they could be dissolved not only in some high boiling solvents such as DMF, NMP, DMAc, and m-Cresol at room temperature, but also in some low boiling solvents such as CHCl3, CH2Cl2, and THF. Their solubility in most solvents could exceed 10 wt%, and the flexible membranes could be obtained by casting their solutions. The prepared membranes exhibited good gas separation properties. The permeability coefficients of PI 3c for CO2 and O2 were up to 124.6 and 42.8 barrer, respectively, and the selectivity coefficients for CO2/CH4 and O2/N2 were 14.7 and 3.3, respectively. The membranes had light color and good optical transmission. Their optical transmittance at 450 nm wavelength was in the range of 67%−79%, and the cutoff wavelength was in the range of 310−348 nm. They also had good thermal properties with glass transition temperature (Tg) values in the range of 264−302 °C. In addition, these membranes possessed good mechanical properties with tensile strength ranging between 77.8−87.4 MPa, initial modulus ranging between 1.69−1.82 GPa, and elongation at break ranging between 4.8%−6.1%.
Antibacterial and pH-responsive Quaternized Hydroxypropyl Cellulose-g-Poly(THF-co-epichlorohydrin) Graft Copolymer: Synthesis, Characterization and Properties
Jin-Rui Deng, Cong-Lei Zhao, Yi-Xian Wu
Corrected proof , doi: 10.1007/s10118-020-2372-3
[Abstract](175) [FullText HTML](104) [PDF 1244KB](16)
The novel quaternized hydroxypropyl cellulose-g-poly(THF-co-epichlorohydrin) graft copolymers, HPC-g-QCP(THF-co-ECH), have been successfully synthesized to combine the properties from hydrophilic hard HPC biomacromolecular backbone and hydrophobic flexible polyether branches. Firstly, the P(THF-co-ECH) living chains were synthesized by cationic ring-opening copolymerization of THF with ECH. Secondly, P(THF-co-ECH) living chains were grafted onto HPC backbone by reaction with ―OH groups along HPC to produce HPC-g-P(THF-co-ECH) graft copolymers. Thirdly, the mentioned graft copolymers were quaternized by reaction with ternary amine to generate functionalized HPC-g-QCP(THF-co-ECH). The HPC-g-QCP(THF-co-ECH) graft copolymers exhibited good antibacterial ability against S. aureus or E. coli bacteria. The ibuprofen (IBU)-loaded microparticles of HPC-g-(QC)P(THF-co-ECH) graft copolymers were prepared by electrospraying. The in vitro pH-responsive drug-release behavior of IBU reached up to 75% of drug-loaded at pH = 7.4. This quaternized graft copolymer was beneficial to solving the problems of a burst effect and fast release of HPC as drug carriers.
Kinematics of Non-axially Positioned Vesicles through a Pore
Yun-Long Han, Ming-Ming Ding, Rui Li, Tong-Fei Shi
Corrected proof , doi: 10.1007/s10118-020-2375-0
[Abstract](199) [FullText HTML](90) [PDF 766KB](4)
We employ finite element method to investigate the kinematics of non-axially positioned vesicles through a pore. To complete the coupling between fluid flow and the vesicle membranes, we use the fluid structure interactions with the arbitrary Lagrangian Eulerian method. Our results demonstrate that the vesicles show different deformations in migration process, in turn an oblique ellipse-shape, slipper-shape, oval-shape. We find that the rotation angle of non-axially positioned vesicles mainly shows the trend of increase, besides the small fluctuation induced by deformation relaxation. Moreover, when the vesicles move towards the axis of the channel, the rotation angle exhibits a decrease because of the decrease of the shear force. However, rotation of axially positioned vesicles hardly occur due to symmetrical shear force. Our results further indicate that the rotation is faster nearby the pore for non-axially positioned vesicles. Our work answers the mapping between the positions of vesicles and deformed states, as well as the change of rotation angle and rotation velocity, which can provide helpful information on the utilization of vesicles in pharmaceutical, chemical, and physiological processes.
Enhanced Crystallization Rate of Poly(L-lactide)/Hydroxyapatite-graft-poly(D-lactide) Composite with Different Processing Temperatures
Min Wang, Lei-Chu You, Yu-Qi Guo, Ni Jiang, Zhi-Hua Gan, Zhen-Bo Ning
Corrected proof , doi: 10.1007/s10118-020-2374-1
[Abstract](226) [FullText HTML](123) [PDF 2987KB](12)
Hydroxyapatite-graft-poly(D-lactide) (HA-g-PDLA) was synthesized by ring-opening polymerization with HA as initiator and stannous octanoate (Sn(Oct)2) as catalyst. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) results indicate that PDLA chains are successfully grafted onto HA particles by covalent bond. Under two different processing temperatures (190 and 230 °C), the effect of the grafted PDLA chains on the crystallization behavior of poly(L-lactide)/HA-g-PDLA (PLLA/HA-g-PDLA) composite was investigated in the current study, comparing to neat PLLA and its four composites (PLLA/HA, PLLA/HA-g-PLLA, PLLA/PDLA, and PLLA/HA/PDLA). The crystallization rate of PLLA/HA-g-PDLA composite is highly enhanced comparing to PLLA, PLLA/HA and PLLA/HA-g-PLLA composites in which there are no stereocomplex (SC) crystallites. In addition, when the processing temperature rises from 190 °C to 230 °C, the acceleration of PLLA crystallization in PLLA/HA-g-PDLA composite is not influenced so much as other composites containing SC crystallites, such as PLLA/HA/PDLA or PLLA/PDLA. The differential scanning calorimetry (DSC) results demonstrate that even without SC crystallites, the crystallization of PLLA can still be accelerated a lot in this composite. This may be related to the interaction between the grafted PDLA chains and the amorphous PLLA chains in PLLA/HA-g-PDLA composite. The isothermal crystallization kinetics studies indicate that the nature of nucleation and crystal growth of PLLA/HA-g-PDLA composite are more likely 3D crystalline growth with heterogeneous nucleation mode, which are different from PLLA or other composites. This investigation could shed new light on the application of PLLA/HA composites.
Conjugated Polymers as Hole Transporting Materials for Solar Cells
Dan Ti, Kun Gao, Zhi-Pan Zhang, Liang-Ti Qu
Corrected proof , doi: 10.1007/s10118-020-2369-y
[Abstract](259) [FullText HTML](136) [PDF 3397KB](12)
In principle, conjugated polymers can work as electron donors and thus as low-cost p-type organic semiconductors to transport holes in photovoltaic devices. With the booming interests in high-efficiency and low-cost solar cells to tackle global climate change and energy shortage, hole transporting materials (HTMs) based on conjugated polymers have received increasing attention in the past decade. In this perspective, recent advances in HTMs for a range of photovoltaic devices including dye-sensitized solar cells (DSSCs), perovskite solar cells (PSCs), and silicon (Si)/organic heterojunction solar cells (HSCs) are summarized and perspectives on their future development are also presented.
Facile Preparation of Electromagnetic Interference Shielding Materials Enabled by Constructing Interconnected Network of Multi-walled Carbon Nanotubes in a Miscible Polymeric Blend
Qi-Yan Zhang, Han-Song Li, Bao-Hua Guo, Zhao-Xia Guo, Jian Yu
Corrected proof , doi: 10.1007/s10118-020-2370-5
[Abstract](283) [FullText HTML](156) [PDF 332KB](33)
Electromagnetic interference (EMI) shielding materials are in great demand in electronic equipment and our surrounding environment to resist the increasing serious radiation pollution. Compared with their metal counterparts, conductive polymer composites (CPCs) have unique advantages of lightweight, corrosive resistance, low cost, and excellent processability, and are therefore an ideal choice for developing high-performance EMI shielding materials. However, CPCs based EMI shielding materials are limited to high filler loading, which caused poor mechanical properties and processability. Here, we demonstrate a facile and highly scalable approach to develop high-performance EMI shielding materials with low filler loading by using miscible poly(phenylene oxide)/polystyrene (PPO/PS) blend as the matrix. In contrast to PS/carbon nanotubes (CNTs) composites, PPO/PS/CNTs composites show much higher EMI shielding effectiveness caused by good dispersion of CNTs and highly interconnected conductive network. An excellent EMI shieling effectiveness of 23−25 dB is achieved for PPO/PS/10%CNTs composites with a thickness of only 375 μm, which is superior to most of reported polymer/CNTs composites prepared by melt-compounding. In addition, the results show that although absorption is the major shielding mechanism, the contribution of reflection is also important and closely related to the connectivity of conductive network, as well as the electrical conductivity of the CPCs.
Side Chain Engineering of Sulfonated Poly(arylene ether)s for Proton Exchange Membranes
Xiang Zhang, Zhi-Wen Li, Xia-Lin Chen, Dong-Yang Chen, Yu-Ying Zheng
Corrected proof , doi: 10.1007/s10118-020-2371-4
[Abstract](265) [FullText HTML](139) [PDF 1154KB](33)
Proton conductivity of proton exchange membranes (PEMs) strongly relies on microscopic morphology, which can be modulated by engineering the distribution of ionic groups. Herein, poly(arylene ether)s with densely distributed allyl functionalities are polymerized from a tetra-allyl bisphenol A monomer. The subsequent thiol-ene addition with sodium 3-mercapto-1-propanesulfonate yields comb-shaped sulfonated fluorinated poly(arylene ether)s (SFPAEs) with ion exchange capacities (IECs) ranging from 1.29 mmol·g−1 to 1.78 mmol·g−1. These SFPAEs exhibit superior proton conductivity over the whole temperature range, which is attributed to the enhanced hydrophilic/hydrophobic phase separation as evidenced by small angle X-ray scattering characterizations. The SFPAE-4-40 with an IEC of 1.78 mmol·g−1 shows the largest proton conductivity of 93 mS·cm−1 at room temperature under fully hydrated condition, higher than that of Nafion 212. Furthermore, the vanadium redox flow battery (VRFB) assembled with SFPAE-4-40 separator exhibits higher energy efficiency than the VRFB assembled with Nafion 212.
Preparation and Characterization of Poly(vinyl alcohol)/ZIF-8 Porous Composites by Ice-templating Method with High ZIF-8 Loading Amount
Xuan-He Yang, Yan-Qing Yao, Mu-Hua Huang, Chun-Peng Chai
Corrected proof , doi: 10.1007/s10118-020-2368-z
[Abstract](203) [FullText HTML](99) [PDF 527KB](12)
A bulk Poly(vinyl alcohol)/ZIF-8 (PVA/ZIF-8) porous composite with aligned porous structure was prepared by ice-templating method. The microstructure of PVA/ZIF-8 porous composites was characterized by scanning electron microscopy (SEM). The results showed that the composites had regular pore structure and ZIF-8 nanoparticles were evenly distributed on the skeleton of PVA. X-ray diffraction (XRD) test results showed that the crystalline structure of ZIF-8 was well preserved in the composites. The specific surface area of the composite was characterized by nitrogen adsorption/desorption test. The specific surface area of the composite was up to 1160 m2·g–1. PVA/ZIF-8 porous composites could also support a certain weight with almost no volume shrinkage. The carbon dioxide adsorption quantity of the composite was up to 11.3 cm3·g–1, proving that PVA/ZIF-8 porous composite has a good application prospect in the field of carbon dioxide adsorption.
Thermal Expansion Behavior of Poly(amide-imide) Films with Ultrahigh Tensile Strength and Ultralow CTE
Lan Bai, Lei Zhai, Min-Hui He, Chang-Ou Wang, Song Mo, Lin Fan
Corrected proof , doi: 10.1007/s10118-020-2366-1
[Abstract](203) [FullText HTML](89) [PDF 558KB](9)
A series of novel poly(amide-imide) (PAI) films with different amide contents were prepared from pyromellitic dianhydride and four amide-containing diamines. These PAI films exhibited excellent mechanical and thermal properties with tensile strength of 203.7−297.4 MPa and Tg above 407 °C. The rigid backbone structures combined with strong intermolecular interactions provided PAI films with ultralow in-plane CTE values from −4.17 ppm/°C to −0.39 ppm/°C in the temperature range of 30−300 °C. The correlation between thermal expansion behavior and aggregation structures of PAI film was investigated. The results suggested that hydrogen bonding interactions could be maintained even at high temperature, thus resulting in good dimension reversibility of films in multiple heating-cooling cycles. It is demonstrated that dimensional stabilities of PAI films are determined by the rigidity, orientation, and packing of molecular chains. Heat-resistant PAI films with ultralow CTE can be developed as flexible substrates by regulating backbones and aggregation structures for optoelectronic application.
General Model of Temperature-dependent Modulus and Yield Strength of Thermoplastic Polymers
Ping-Yuan Huang, Zhan-Sheng Guo, Jie-Min Feng
Corrected proof , doi: 10.1007/s10118-020-2360-7
[Abstract](254) [FullText HTML](88) [PDF 834KB](12)
A general model was developed to predict the temperature-dependent modulus and yield strength of different thermoplastic polymers. This model, which depends on only two parameters with clear and specific physical meanings, can describe the temperature-dependent modulus and yield strength of thermoplastic polymers over the full glass transition region. The temperature-dependent modulus and yield strength of three thermoplastic polymers were measured by uniaxial tension tests over a temperature range of 243−383 K. The predictions showed excellent agreement with the experimental data. Sensitivity analysis of model input parameters showed negligible effect on the present general model. The universality of the present general model was further validated, showing excellent agreement with published experimental data on other thermoplastic polymers and their composites.
Anionic Polymerization of Butadiene Using Lithium/Potassium Multi-metallic Systems: Influence on Polymerization Control and Polybutadiene Microstructure
Antoine Forens, Kevin Roos, Charlotte Dire, Benoit Gadenne, Stéphane Carlotti
Corrected proof , doi: 10.1007/s10118-020-2355-4
[Abstract](246) [FullText HTML](79) [PDF 240KB](12)
Thermal, mechanical, and viscoelastic properties of polybutadiene-based rubber materials are highly dependent on polybutadiene microstructure. The use of polar modifier in association with alkyllithium is a well-known method to obtain polybutadiene with a high vinyl content. Another approach is to use bimetallic initiating species such as alkyllithium combined to heavier alkali metal alkoxide (RONa, ROK…). The polymerization control is nevertheless not achieved and several parameters were found to influence it. Using bimetallic initiating systems based on alkyllithium and a potassium alkoxide, alkyllithium structure, initiator preformation time, and initiator composition were identified as parameters influencing the anionic polymerization process of butadiene and/or polybutadiene microstructure. In addition, the use of trimetallic systems based on alkyllithium, potassium alkoxide, and alkylaluminum was investigated in order to prevent side reactions regardless of the [K]/[Li] ratio and of the initiator preformation time.
Conformational Properties of Comb-shaped Polyelectrolytes with Negatively Charged Backbone and Neutral Side Chains Studied by a Generic Coarse-grained Bead-and-Spring Model
Jian-Hua Chen, Li-Qun Lu, Hong-Xia Zhao, Yong Yang, Xin Shu, Qian-Ping Ran
Corrected proof , doi: 10.1007/s10118-020-2350-9
[Abstract](297) [FullText HTML](74) [PDF 368KB](7)
A generic coarse-grained bead-and-spring model, mapped onto comb-shaped polycarboxylate-based (PCE) superplasticizers, is developed and studied by Langevin molecular dynamics simulations with implicit solvent and explicit counterions. The agreement on the radius of gyration of the PCEs with experiments shows that our model can be useful in studying the equilibrium sizes of PCEs in solution. The effects of ionic strength, side-chain number, and side-chain length on the conformational behavior of PCEs in solution are explored. Single-chain equilibrium properties, including the radius of gyration, end-to-end distance and persistence length of the polymer backbone, shape-asphericity parameter, and the mean span dimension, are determined. It is found that with the increase of ionic strength, the equilibrium sizes of the polymers decrease only slightly, and a linear dependence of the persistence length of backbone on the Debye screening length is found, in good agreement with the theory developed by Dobrynin. Increasing side-chain numbers and/or side-chain lengths increases not only the equilibrium sizes (radius of gyration and mean span) of the polymer as a whole, but also the persistence length of the backbone due to excluded volume interactions.
Ultrasound-responsive Homopolymer Nanoparticles
Bo Yang, Jian-Zhong Du
Corrected proof , doi: 10.1007/s10118-020-2345-6
[Abstract](479) [FullText HTML](86) [PDF 890KB](18)
Noninvasive ultrasound is a more effective strategy for on-demand drug delivery of polymeric nanoparticles than many other stimuli. However, the preparation of ultrasound-responsive homopolymer nanoparticles is still very challenging. In this study, we disclose the regulating factors of ultrasound responsiveness of homopolymer nanoparticles and the disaggregation behavior of homopolymer nanoparticle aggregates. Homopolymer nanoparticles such as vesicles and large compound micelles (LCMs) are self-assembled from poly(methoxyethyl methacrylate) (PMEMA) and poly(amic acid) (PAA), respectively. The ultrasound responsiveness of PAA vesicles at metastable state could be regulated by tuning the self-assembly temperature (Ts), and was optimized when Ts is around the glass transition temperature (Tg) of PAA. However, the PMEMA LCMs did not respond to ultrasound as they are at stable state. On the other hand, poly(2-(2-ethoxyethoxy)ethyl acrylate) (PEEA) could self-assemble into vesicle aggregates or complex micelle aggregates, which were dissociated upon sonication. Overall, the above findings provide us with a fresh insight for designing ultrasound-responsive polymeric nanoparticles.
Chloromethylation and Quaternization of Poly(aryl ether ketone sulfone)s with Clustered Electron-rich Phenyl Groups for Anion Exchange Membranes
Lei Xiong, Yuan-Fang Hu, Zi-Gui Zheng, Zai-Lai Xie, Dong-Yang Chen
Corrected proof , doi: 10.1007/s10118-020-2340-y
[Abstract](249) [FullText HTML](60) [PDF 553KB](20)
Ion segregation is critically important for achieving high ion conductivity for anion exchange membranes (AEMs). Herein, a new bisphenol monomer bearing ten electron-rich phenyl groups was designed and polymerized with various amounts of electron-deficient 4,4′-dihydroxydiphenylsulfone and 4,4′-difluorobenzophenone to yield dense and selective reaction sites for chloromethylation and quaternization. As the most challenging step, chloromethylation was optimized by tuning the reaction temperature, reaction time, and reactant ratios. Ion exchange capacity, water uptake, anion conductivity, mechanical stability, and alkaline stability of the resulting AEMs were characterized in detail. It is found that chloromethylation reaction needed to be carried out at low equivalent of chloromethylation agents to avoid undesirable crosslinking. The QA-PAEKS-20 sample with an IEC of 1.19 mmol·g−1 exhibited a Cl conductivity of 11.2 mS·cm−1 and a water uptake of 30.2% at 80 °C, which are promising for AEM applications.
Comparative Investigation on Step-cycle Tensile Behaviors of Two Bimodal Pipe-grade Polyethylene with Different Slow Crack Growth Resistance
Yan-Qin Huang, Qing-Long Zhang, Xiao-Ying Lu, Yi-Bin Gong, Hao Zhou, Jia-Chun Feng
Corrected proof , doi: 10.1007/s10118-020-2364-3
[Abstract](166) [FullText HTML](61) [PDF 802KB](8)
In this work, step-cycle tensile behavior of two bimodal polyethylene (PE) materials, a PE100 grade pipe material, XS10, and a PE100-RC (Resistant Crack) grade pipe material, XSC50, was comparatively investigated. By decomposing the strain into a recoverable part and an unrecoverable part, it was found that the deformation recovery capability of XSC50 during stretching was larger than that of XS10. Structural evolution characterized by in situ synchrotron small angle X-ray scattering indicated that the fragmentation of initial crystals in XSC50 occurred at lower strain than in XS10. Considering that XSC50 had relatively small lamellar thickness and similar crystallinity to XS10, we speculated that the larger deformation recovery capability of XSC50 during stretching probably derived from stronger entangled amorphous region caused by larger density of tie molecules and entanglements, which were usually regarded to have a significant influence on the slow crack growth (SCG) resistance of PE materials. As expected, the experimental result of strain hardening modulus test suggested that the deformation recovery capability during stretching was positively correlated with the SCG resistance for XS10 and XSC50 used in this work. The step-cycle tensile test had the potential to be developed into a supplement for comparison of SCG resistance of PE materials.
Single-wavelength Excited Ratiometric Fluorescence pH Probe to Image Intracellular Trafficking of Tobacco Mosaic Virus
Si-Jia Gao, Zhuang Li, Zhi-Cheng Sun, Jin-Yue Wen, Fu-Rong Li, Xiao-Yang Du, Yan Liu, Ye Tian, Zhong-Wei Niu
Corrected proof , doi: 10.1007/s10118-020-2365-2
[Abstract](168) [FullText HTML](63) [PDF 1196KB](4)
As a typical plant virus which has biocompatibility and high transfection efficiency, tobacco mosaic virus (TMV) has shown broad application potential in drug or gene delivery field. Elucidating its intracellular trafficking is of great importance in investigation of its cytotoxicity, targeting site, and delivery efficiency, and is advantageous to designing new TMV-based drug delivery systems with different targets. By taking advantage of the regulated pH value of different organelles in a mammalian cell, we exploit a pH detection strategy to investigate the intracellular trafficking pathway of TMV. Here, we report a single-wavelength excited ratiometric fluorescent pH probe. This probe is constructed by simultaneously coupling pH-sensitive fluorescein isothiocyanate (FITC) and pH-insensitive rhodamine B isothiocyanate (RBIRC) onto the inner surface of TMV. The fluorescence intensity ratio of FITC to RBITC excited at 488 nm responds specifically towards pH value over other interferential agents. By taking use of this single-wavelength excited ratiometric pH probe and confocal laser scanning microscopy, it is shown that the endocytosed TMV is located in a pH decreasing microenvironment and eventually enters lysosomes. This work may provide important guidance on construction of TMV-based nano carriers.
The Role of Mold Temperature on Morphology and Mechanical Properties of PE Pipe Produced by Rotational Shear
Zu-Chen Du, Hao Yang, Xie-Huai Luo, Ze-Xiang Xie, Qiang Fu, Xue-Qin Gao
Corrected proof , doi: 10.1007/s10118-020-2363-4
[Abstract](159) [FullText HTML](76) [PDF 6239KB](4)
The role of mold temperature on the morphology and properties of rotational shearing polyethylene (PE) pipes was studied via a self-developed rotational shear system (RSS). The result indicated that when the mold temperature was 150 °C, the hoop tensile strength and Vicat softening temperature were enhanced rapidly, which were 383.6% and 137.9% higher than those of the conventional PE pipes, respectively. Morphology and crystal structure studies by SEM and DSC revealed that once the rotational shear was applied, the shish-kebab structure began to appear. With the increase of the mold temperature, due to the relaxation of most of the oriented molecular chains, the preservation of shish-kebab structure became difficult. When the mold temperature was 190 °C, only the inner layer of the pipes, where the cooling rate was the largest, could preserve the shish-kebab structure. According to WAXD, there was less shish structure, and the growth of kebab was distorted in the inner layer of the pipes at 210 °C. The result of SAXS suggested that the length of shish changed most within the temperature range from 170 °C to 190 °C. The results of DSC and WAXD showed less change in crystallinity and degree of orientation between the two temperatures. It can be concluded that the reduction of shish length leads to a decrease in mechanical properties and heat-resistance.
Probing Intermittent Motion of Polymer Chains in Weakly Attractive Nanocomposites
Li-Jun Dai, Cui-Liu Fu, You-Liang Zhu, Zhan-Wei Li, Zhao-Yan Sun
Corrected proof , doi: 10.1007/s10118-020-2352-7
[Abstract](268) [FullText HTML](86) [PDF 1485KB](23)
In this study, we investigate the motion of polymer segments in polymer/nanoparticle composites by varying nanoparticle (NP) volume fractions. By studying the probability distribution of segment displacement, segment trajectory, and the square displacement of segment, we find the intermittent motion of segments, accompanied with the coexistence of slow and fast segments in polymer nanocomposites (PNCs). The displacement distribution of segments exhibits an exponential tail, rather than a Gaussian form. The intermittent dynamics of chain segments is comprised of a long-range jump motion and a short-range localized motion, which is mediated by the weakly attractive interaction between NP and chain segment and the strong confinement induced by NPs. Meanwhile, the intermittent motion of chain segments can be described by the adsorption-desorption transition at low particle loading and confinement effect at high particle loading. These findings may provide important information for understanding the anomalous motion of polymer chains in the presence of NPs.
Mechanistic Transformations Involving Radical and Cationic Polymerizations
Gorkem Yilmaz, Yusuf Yagci
Corrected proof , doi: 10.1007/s10118-020-2367-0
[Abstract](204) [FullText HTML](73) [PDF 649KB](5)
Mechanistic transformation approach has been widely applied in polymer synthesis due to its unique feature combining structurally different polymers prepared by different polymerization mechanisms. Reported methods for the formation of block and graft copolymers through mechanistic transformation involve almost all polymerizations modes. However, certain polymerization processes require extensive purification processes, which can be time-consuming and problematic. Recent developments on controlled/living polymerizations involving radical and cationic mechanisms with the ability to control molecular weight and functionality led to new pathways for mechanistic transformations. In this mini-review, we systematically discussed relevant advances in the field through three main titles namely (i) from radical to cationic mechanism, (ii) from cationic to radical mechanism, and (iii) application of specific catalyst systems for both radical and cationic polymerizations.
Molecular Mobility in the Amorphous Phase Determines the Critical Strain of Fibrillation in the Tensile Stretching of Polyethylene
Rui Li, Guo-Xing Yang, Ya-Nan Qin, Li Liu, Zhi-Yong Jiang
Corrected proof , doi: 10.1007/s10118-020-2362-5
[Abstract](199) [FullText HTML](81) [PDF 548KB](6)
The microstructural development of bimodal high density polyethylene subjected to tensile deformation was investigated as a function of strain after annealing at different temperatures by means of a scanning synchrotron small angle X-ray scattering (SAXS) technique. Two different deformation mechanisms were activated in sequence upon tensile deformation: intralamellar slipping of crystalline blocks dominates the deformation behavior at small deformations whereas a stress-induced crystalline block fragmentation and recrystallization process occurs at a critical strain yielding new crystallites with the molecular chains preferentially oriented along the drawing direction. The critical strain associated with the lamellar-to-fibrillar transition was found to be ca. 0.9 in bimodal sample, which is significantly larger than that observed for unimodal high-density polyethylene (0.4). This observation is primarily due to the fact that the bimodal sample possesses a greater mobility of the amorphous phase and thereby a reduced modulus of the entangled amorphous network. The conclusion of the mobility of the amorphous phase as a determining factor for the critical strain was further proven by the 1H-NMR T2 relaxation time. All these findings contribute to our understanding of the excellent slow crack growth resistance of bimodal polyethylene for pipe application.
Ethylene Polymerization and Copolymerization with Polar Monomers by Benzothiophene-bridged BPMO-Pd Catalysts
Hong-Liang Mu, Jun-Hao Ye, Guang-Lin Zhou, Kang-Kang Li, Zhong-Bao Jian
Corrected proof , doi: 10.1007/s10118-020-2359-0
[Abstract](220) [FullText HTML](65) [PDF 331KB](7)
A series of new bisphosphine-monoxide (BPMO) ligands based on benzothiophene backbone and the corresponding palladium complexes {к2-2-P(O)(Ph)2-3-PR1R2-C8H4S}PdMeCl { 2a : R1 = R2 = Ph; 2b : R1 = R2 = 2-OMe-Ph; 2c : R1 = R2 = 2-CF3-Ph; 2d : R1 = Ph, R2 = 2-(2′,6′-(OMe)2C6H3)-C6H4} were synthesized and fully characterized by 1H-, 13C-, 31P-, and 2D-NMR spectroscopy and single-crystal X-ray diffraction. In the presence of Na+B[3,5-(CF3)2C6H3]4 (NaBArF), these complexes showed very high activities (up to 2.0 × 107 g·mol–1·h–1) for ethylene polymerization. More significantly, these catalysts enabled the copolymerization of ethylene with a broad scope of commercially available polar comonomers such as acrylates, acrylic acid, acrylonitrile, vinyltrialkoxysilane, allyl acetate, and long-chain 6-chloro-1-hexene to give functionalized polyethylene with reasonable catalytic activities (up to 106 g·mol–1·h–1) and incorporations (up to 5.3 mol%). This contribution suggests that, besides the modulation of conventionally steric and electronic factors, the connectivity (at different linking positions) of BPMO (P,O) donors to the heteroaryl backbone also greatly influences the catalyst properties in terms of catalytic activity, polymer branching content, comonomer scope, and comonomer incorporation.
Achieving Efficient Thick Film All-polymer Solar Cells Using a Green Solvent Additive
Zhen-Ye Li, Wen-Kai Zhong, Lei Ying, Ning Li, Feng Liu, Fei Huang, Yong Cao
Corrected proof , doi: 10.1007/s10118-020-2356-3
[Abstract](267) [FullText HTML](63) [PDF 439KB](22)
Advances in organic photovoltaic technologies have been geared toward industrial high-throughput printing manufacturing, which requires insensitivity of photovoltaic performance regarding to the light-harvesting layer thickness. However, the thickness of light-harvesting layer for all polymer solar cells (all-PSCs) is often limited to about 100 nm due to the dramatically decreased fill factor upon increasing film thickness, which hampers the light harvesting capability to increase the power conversion efficiency, and is unfavorable for fabricating large-area devices. Here we demonstrate that by tuning the bulk heterojunction morphology using a non-halogenated solvent, cyclopentyl methyl ether, in the presence of a green solvent additive of dibenzyl ether, the power conversion efficiency of all-PSCs with photoactive layer thicknesses of over 500 nm reached an impressively high value of 9%. The generic applicability of this green solvent additive to boost the power conversion efficiency of thick-film devices is also validated in various bulk heterojunction active layer systems, thus representing a promising approach for the fabrication of all-PSCs toward industrial production, as well as further commercialization.
The Crystallization and Melting Behaviors of PDLA-b-PBS-b-PDLA Tri-block Copolymers
Cong-Shu Feng, Yun Chen, Jun Shao, Gao Li, Hao-Qing Hou
Corrected proof , doi: 10.1007/s10118-020-2361-6
[Abstract](173) [FullText HTML](59) [PDF 1180KB](9)
In this study, the poly(D-lactide)-block-poly(butylene succinate)-block-poly(D-lactide) (PDLA-b-PBS-b-PDLA) triblock copolymers with a fixed length of PBS and various lengths of PDLA are synthesized, and the crystallization behaviors of the PDLA and PBS blocks are investigated. Although both the crystallization behaviors of PBS and PDLA blocks depend on composition, they exhibit different variations. For the PDLA block, its crystallization behaviors are mainly influenced by temperature and block length. The crystallization signals of PDLA block appear in the B-D 2-2 specimen, and these signals get enhanced with PDLA block length. The crystallization rates tend to decrease with increasing PDLA block lendth during crystallizing at 90 and 100 °C. Crystallizing at higher temperature, the crystallization rates increase at first and then decrease with block length. The crystallization rates decrease as elevating the crystallization temperature. The melting temperatures of PDLA blocks increase with block lengths and crystallization temperatures. For the PBS block, its crystallization behaviors are mainly controlled by the nucleation and confinement from PDLA block. The crystallization and melting enthalpies as well as the crystallization and melting temperatures of PBS block reduce as a longer PDLA block has been copolymerized, while the crystallization rates of the PBS block exhibit unique component dependence, and the highest rate is observed in the B-D 2-2 specimen. The Avrami exponent of PBS crystallites is reduced as a longer PDLA block is incorporated or the sample is crystallized at higher temperature. This investigation provides a convenient route to tune the crystallization behavior of PBS and PLA.
Fast Computation of Electrostatic Interactions for a Charged Polymer with Applied Field
Hao Lin, Zi-Tong Lei, Ming-Ming Ding, Hong-Jun Wang, Tong-Fei Shi
Corrected proof , doi: 10.1007/s10118-020-2343-8
[Abstract](331) [FullText HTML](77) [PDF 341KB](12)
Using a hybrid simulation approach that combines a finite difference method with a Brownian dynamics, we investigated the motion of charged polymers. Owing to the fact that polymer-solution systems often contain a large number of particles and the charged polymer chains are in a state of random motion, it is a time-consuming task to calculate the electrostatic interaction of the system. Accordingly, we propose a new strategy to shorten the CPU time by reducing the iteration area. Our simulation results illustrate the effect of preset parameters on CPU time and accuracy, and demonstrate the feasibility of the " local iteration” method. Importantly, we find that the increase in the number of charged beads has no significant influence on the time of global iterations and local iterations. For a number of 80 × 80 × 80 grids, when the relative error is controlled below 1.5%, the computational efficiency is increased by 8.7 times in the case that contains 500 charged beads. In addition, for a number of 100 × 100 × 100 grids with 100 charged beads, the computational efficiency can be increased up to 12 times. Our work provides new insights for the optimization of iterative algorithms in special problems.
Molecular Weight Dependence of Associative Behavior in Polyimide/DMF Solutions
Hong-Xiang Chen, En-Song Zhang, Mei Hong, Wei Liu, Xue-Min Dai, Quan Chen, Xue-Peng Qiu, Xiang-Ling Ji
Corrected proof , doi: 10.1007/s10118-020-2358-1
[Abstract](361) [FullText HTML](185) [PDF 428KB](18)
Eight 6FDA-TFDB polyimide (PI) samples with absolute molecular weights ranging from 1.25 × 105 g·mol–1 to 3.11 × 105 g·mol–1 are obtained by precipitation fractionation. Rheological experiments are conducted to determine the influence of molecular weight on the associating behavior of PI in N,N′-dimethylformamide (DMF) solutions in a broad volume fraction, including abnormal steady shear flow, solution heterogeneity, and scaling behavior. Abnormal flow behaviors, i.e., multi-region shear thinning and weak shear thickening, are studied, and these behaviors have not been reported in literature. The heterogeneity of PI/DMF solutions is examined by dynamic rheological test. By plotting ηsp versus ϕ/ϕη, four concentration regions of I–IV can be distinguished for all PI samples with various molecular weights. The scaling results in different concentration regions are in good agreement with the associative polymer theory proposed by Rubinstein and Semenov. The scaling exponents do not show molecular weight dependence in concentration regions I and II. In concentration regions III and IV, the scaling exponents change little when the molecular weight is below 242 k but increase when the molecular weight increases from 242 k to 311 k. This work can help us to understand polyimide solution properties from dilute to semidilute entangled solutions, and will guide the polyimide solution preparation for different processing.
Melt Crystallization of Poly(butylene 2,6-naphthalate)
Qian Ding, Michelina Soccio, Nadia Lotti, Dario Cavallo, René Androsch
Corrected proof , doi: 10.1007/s10118-020-2354-5
[Abstract](243) [FullText HTML](93) [PDF 1497KB](10)
Poly(butylene 2,6-naphthalate) (PBN) is a crystallizable linear polyester containing a rigid naphthalene unit and flexible methylene spacer in the chemical repeat unit. Polymeric materials made of PBN exhibit excellent anti-abrasion and low friction properties, superior chemical resistance, and outstanding gas barrier characteristics. Many of the properties rely on the presence of crystals and the formation of a semicrystalline morphology. To develop specific crystal structures and morphologies during cooling the melt, precise information about the melt-crystallization process is required. This review article summarizes the current knowledge about the temperature-controlled crystal polymorphism of PBN. At rather low supercooling of the melt, with decreasing crystallization temperature, β′- and α-crystals grow directly from the melt and organize in largely different spherulitic superstructures. Formation of α-crystals at high supercooling may also proceed via intermediate formation of a transient monotropic liquid crystalline structure, then yielding a non-spherulitic semicrystalline morphology. Crystallization of PBN is rather fast since its suppression requires cooling the melt at a rate higher than 6000 K·s−1. For this reason, investigation of the two-step crystallization process at low temperatures requires application of sophisticated experimental tools. These include temperature-resolved X-ray scattering techniques using fast detectors and synchrotron-based X-rays and fast scanning chip calorimetry. Fast scanning chip calorimetry allows freezing the transient liquid-crystalline structure before its conversion into α-crystals, by fast cooling to below its glass transition temperature. Subsequent analysis using polarized-light optical microscopy reveals its texture and X-ray scattering confirms the smectic arrangement of the mesogens. The combination of a large variety of experimental techniques allows obtaining a complete picture about crystallization of PBN in the entire range of melt-supercoolings down to the glass transition, including quantitative data about the crystallization kinetics, semicrystalline morphologies at the micrometer length scale, as well as nanoscale X-ray structure information.
Hierarchically Crosslinked Gels Containing Hydrophobic Ionic Liquids towards Reliable Sensing Applications
Xia-Chao Chen, Pei-Ru Sun, Hong-Liang Liu
Corrected proof , doi: 10.1007/s10118-020-2357-2
[Abstract](260) [FullText HTML](84) [PDF 759KB](21)
Human skin can function steadily regardless of surrounding circumstances (dry or wet), while it is still a challenge for artificial ionic skins, which tend to release solvents in dry air and leach electrolytes in wetted state. Herein, a series of hierarchically crosslinked ionogels containing hydrophobic ionic liquids (ILs) is fabricated by combining a crystalline fluorinated copolymer with hydrophobic ILs. With a reasonable combination of nonvolatility, transparency, stretchablility, and sensitivity, such ionogels can work as reliable sensors for real-time monitoring human motions and operate steadily in complex environments as human skin does, which can contribute to the development of durable sensing devices with a simple design.
Surface Patterns of a Tetrahedral Polyelectrolyte Brush Induced by Grafting Density and Charge Fraction
Hong-Ge Tan, Gang Xia, Li-Xiang Liu, Xiao-Hui Niu, Qing-Hai Hao
Corrected proof , doi: 10.1007/s10118-020-2351-8
[Abstract](272) [FullText HTML](100) [PDF 1075KB](6)
A tetrahedral polyelectrolyte brush in the presence of trivalent counterions is researched under the condition of good solution by means of molecular dynamics simulations. Grafting density and charge fraction are varied to generate a series of surface patterns. Lateral microphase separation happens and various interesting pinned patches appear at appropriate charge fraction and grafting density. Through a careful analysis on the brush thickness, the pair correlation functions, the distributions of net charge, and the four states of trivalent counterions in the brush, we find that the ordered surface patterns and special properties are induced by the pure electrostatic correlation effect of trivalent ions even in the good solvent. Furthermore, the dependences of electrostatic correlation on the charge fraction of tethered chains are evaluated for fixed grafting density. Also, our results can serve as a guide for precise control over the stimuli-responsive materials rational and self-assembly of nanoparticles.
Preparation of Polyaniline-coated Composite Aerogel of MnO2 and Reduced Graphene Oxide for High-performance Zinc-ion Battery
Jing Mao, Fang-Fang Wu, Wen-Hui Shi, Wen-Xian Liu, Xi-Lian Xu, Gang-Feng Cai, Yi-Wen Li, Xie-Hong Cao
Corrected proof , doi: 10.1007/s10118-020-2353-6
[Abstract](263) [FullText HTML](99) [PDF 947KB](14)
Aqueous zinc-ion batteries, especially Zn-MnO2 battery, have attracted intensive attention owing to their unique features of high capacity, environmental friendliness, and safety. However, the problem of Mn dissolution hinders the development of zinc-ion batteries with long-term usage and high-rate performance. In this work, a novel preparation method for the polyaniline (PANI)-coated composite aerogel of MnO2 and rGO (MnO2/rGO/PANI) electrode is reported. The obtained composite possesses high electrical conductivity, and also effectively suppresses the dissolution of Mn. The fabricated MnO2/rGO/PANI//Zn battery exhibits a high capacity of 241.1 mAh·g−1 at 0.1 A·g−1, and an excellent capacity retention of 82.7% after 600 charge/discharge cycles. In addition, the rapid diffusion coefficient of the MnO2/rGO/PANI electrode was further examined by galvanostatic intermittent titration technique. This work provides new insights into the development of high-performance Zn-MnO2 battery with a better understanding of its diffusion kinetics.
Ethylene-Propene Copolymerization with C1-symmetric ansa-Fluorenyl-zirconocene Catalysts: Effects of Catalyst Structure and Comonomer on Molar Mass
Simona Losio, Laura Boggioni, Massimiliano Cornelio, Abbas Razavi, Incoronata Tritto
Corrected proof , doi: 10.1007/s10118-020-2348-3
[Abstract](161) [FullText HTML](84) [PDF 469KB](4)
Ethylene-propene copolymers have been synthesized by three C1-symmetric metallocene molecules ( 1 , 2 , and 3 ), having tert-butyl substituents on the Cp moiety, on the fluorenyl moiety, or on both moieties, and methylaluminoxane (MAO) at different polymerization temperatures and monomer concentrations. Copolymers were investigated by 13C-NMR, 1H-NMR, and SEC analyses. A relationship was found between [EEE]/[E] ratios and copolymer molar masses in each series: the higher the [EEE]/[E] ratio, the lower the copolymer molar mass. At parity of [EEE]/[E] ratio, copolymer molar mass follows the order 1 >> 3 > 2 . Chain end group analysis reveals that copolymers mainly terminate when propene is the last inserted unit, confirming that it is the greater facility of Mt-P-E-poly(E-co-P) to terminate that influences the copolymer molar mass. Among the catalysts considered, catalyst 1 , which gives syndiospecific polypropene, gives greater activities, comonomer incorporation, and molar masses. Catalyst 3 , which gives isospecific polypropene, in copolymerization performs better than 2 , having the same bridge, with respect to activities, ethylene content, and molar masses. The good performance of this catalyst arises from the not necessity of polymer chain to back skip when ethylene is the last inserted unit.
Conductivity of Poly(methyl methacrylate)/Polystyrene/Carbon Black and Poly(ethyl methacrylate)/Polystyrene/Carbon Black Ternary Composite Films
Hua-Gen Xu, Mu-Chao Qu, Ya-Min Pan, Dirk W. Schubert
Corrected proof , doi: 10.1007/s10118-020-2349-2
[Abstract](478) [FullText HTML](94) [PDF 5683KB](17)
Poly(methyl methacrylate) (PMMA)/polystyrene (PS)/carbon black (CB) and poly(ethyl methacrylate) (PEMA)/PS/CB ternary composite films were obtained using solution casting technique to investigate double percolation effect. In both PMMA/PS/CB and PEMA/PS/CB ternary composite films, the CB particles prefer to locate into PS phase based on the results of calculating wetting coefficient, which is also confirmed by SEM images. The conductivity of the films was investigated, and the percolation threshold (ϕc) of both ternary composite films with different polymer blend ratios was determined by fitting the McLachlan GEM equation. Conductivity of PMMA/PS/CB ternary composite films showed a typical double percolation effect. However, due to the double emulsion structure of PEMA/PS polymer blends, the PEMA/PS/CB ternary composite films (PEMA/PS = 50/50) showed a higher ϕc, even CB only located in PS phase, which conflicts with the double percolation effect. A schematic diagram combined with SEM images was proposed to explain this phenomenon.
Role of Hydrodynamic Interactions in the Deformation of Star Polymers in Poiseuille Flow
Zhen-Yue Yang, Xiao-Fei Tian, Li-Jun Liu, Ji-Zhong Chen
Corrected proof , doi: 10.1007/s10118-020-2346-5
[Abstract](349) [FullText HTML](125) [PDF 1662KB](25)
Stretching polymer in fluid flow is a vital process for studying and utilizing the physical properties of these molecules, such as DNA linearization in nanofluidic channels. We studied the role of hydrodynamic interactions (HIs) in stretching a free star polymer in Poiseuille flow through a tube using mesoscale hydrodynamic simulations. As increasing the flow strength, star polymers migrate toward the centerline of tube due to HIs, whereas toward the tube wall in the absence of HIs. By analyzing the end monomer distribution and the perturbed flow around the star polymer, we found that the polymer acts like a shield against the flow, leading to additional hydrodynamic drag forces that compress the arm chains in the front of the star center toward the tube axis and lift the arm chains at the back toward the tube wall. The balanced hydrodynamic forces freeze the polymer into a trumpet structure, where the arm chains maintain a steady strongly stretched state at high flow strength. In contrast, the polymer displays remarkably large conformational change when switching off HIs. Our simulation results explained the coupling between HIs and the structure of star polymers in Poiseuille flow.
Unsymmetric Side Chains of Indacenodithiophene Copolymers Lead to Improved Packing and Device Performance
Ying Yang, Tong Shan, Jian Cao, Hua-Chun Wang, Ji-Kang Wang, Hong-Liang Zhong, Yun-Xiang Xu
Corrected proof , doi: 10.1007/s10118-020-2342-9
[Abstract](326) [FullText HTML](114) [PDF 449KB](21)
Two conjugated polymers (PuIDTBD and PuIDTQ) with unsymmetric side chains have been prepared for polymer solar cells using two other polymers (PIDTBD and PIDTQ) with symmetric side chains as control compounds. The combination of methyl and 4-hexylphenyl side chains on the same bridged carbon can ensure good solubility, decrease π-π stacking distances, and bring proper miscibility with PC71BM simultaneously. Therefore, the corresponding polymer solar cells (PSCs) based on donor polymers with unsymmetric side chains exhibited enhanced short-circuit current density (JSC) and power conversion efficiency (PCE) compared with those of control polymers. The PIDTBD and PIDTQ based devices possessed low PCE of 2.13% and 1.48%, while PCEs of devices based on PuIDTBD and PuIDTQ were improved to 3.93% and 4.12%, respectively. The results demonstrate that unsymmetric side chain engineering of conjugated polymers is an effective approach to achieve high performance PSCs.
A Facile Strategy for Non-fluorinated Intrinsic Low-k and Low-loss Dielectric Polymers: Valid Exploitation of Secondary Relaxation Behaviors
Chao Qian, Zhen-Guo Fan, Wei-Wen Zheng, Run-Xin Bei, Tian-Wen Zhu, Si-Wei Liu, Zhen-Guo Chi, Matthew P. Aldred, Xu-Dong Chen, Yi Zhang, Jia-Rui Xu
Corrected proof , doi: 10.1007/s10118-020-2339-4
[Abstract](349) [FullText HTML](145) [PDF 425KB](25)
High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming Fifth-Generation Mobile Communications Technology (5G Technology). Herein, a facile design strategy for non-fluorinated intrinsic low-k and low-loss polyimides is reported by fully considering the secondary relaxation behaviors of the polymer chains. A new amorphous non-fluorinated polymer (TmBPPA) with a k value of 2.23 and a loss tangent lower than 3.94 × 10−3 at 104 Hz has been designed and synthesized, which to the best of our knowledge is the lowest value amongst the non-fluorinated and non-porous polymers reported in literature. Meanwhile, TmBPPA exhibits excellent overall properties, such as excellent thermostability, good mechanical properties, low moisture absorption, and high bonding strength. As high-performance flexible circuit materials, all these characteristics are highly expected to meet the present and future demands for high density, high speed, and high frequency electronic circuit used in 5G wireless networks.
Ring-opening Copolymerization of ε-Caprolactone and δ-Valerolactone Catalyzed by a 2,6-Bis(amino)phenol Zinc Complex
Qian Hu, Su-Yun Jie, Pierre Braunstein, Bo-Geng Li
Corrected proof , doi: 10.1007/s10118-020-2347-4
[Abstract](329) [FullText HTML](135) [PDF 1517KB](22)
In combination with methyllithium, a 2,6-bis(amino)phenol zinc complex 1 was used in the ring-opening polymerization of δ-valerolactone in the absence or presence of benzyl alcohol and showed high efficiency, mainly producing cyclic and linear polyvalerolactones, respectively. On the basis of homopolymerization, the ring-opening copolymerization of ε-caprolactone and δ-valerolactone was investigated. The P(CL-co-VL) random copolymers, PCL-b-PVL and PVL-b-PCL diblock copolymers, were prepared by varying the feeding strategy (premixing or sequential feeding). The copolymer composition was adjusted by varying the feeding ratio of two monomers. The structure and thermal properties of obtained polymers were characterized by GPC, 1H-NMR, 13C-NMR, MALDI-TOF mass spectroscopy, and DSC, respectively.
Infectious Behavior in Photo-oxidation of Polymers
Xuan Liu, Xiao-Peng Ren, Rui Yang
Corrected proof , doi: 10.1007/s10118-020-2344-7
[Abstract](279) [FullText HTML](133) [PDF 2386KB](9)
When a polymer is used together with others, its aging process will be affected by the adjacent polymers. This infectious behavior between polymers makes the aging process more complex than that of an individual material. In this study, infectious behavior in photo-oxidation of polymers was investigated. Polypropylenes (PPs), an unstabilized PP and a commercial PP, were chosen as the infection sources. Six typical polymers, high density polyethylene (HDPE), low density polyethylene (LDPE), polystyrene (PS), polycarbonate (PC), poly(ethylene terephthalate) (PET), and polyamide 6 (PA6), were used as the targets. The degree of oxidation of the targets was evaluated by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). An accelerating effect of two infection sources on the photo-oxidation of the target polymers was observed. Potential infectious agents from the infection sources were detected by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and gas chromatography (GC). The acceleration effect of two main infectious agents, i.e. acetone and acetic acid, on the photo-oxidation of the commercial PP was verified. The infectious effect of the infection source on the target polymer was considered to be a comprehensive result of the effects of a variety of infectious agents.
Hofmeister Effect on Thermo-responsive Poly(N-isopropylacrylamide) Hydrogels Grafted on Macroporous Poly(vinyl alcohol) Formaldehyde Sponges
Kai Shi, Di Sha, Jiu-Duo Xu, Xu Yang, Bao-Long Wang, Yan-Xiong Pan, Xiang-Ling Ji
Corrected proof , doi: 10.1007/s10118-019-2320-2
[Abstract](487) [FullText HTML](165) [PDF 5004KB](21)
In this work, the Hofmeister effects of nine kinds of anions at different concentrations on the lower critical solution temperature (LCST) of the macroporous thermo-responsive poly(N-isopropylacrylamide) grafted poly(vinyl alcohol) formaldehyde (PVF-g-PNIPAM) hydrogels are investigated with differential scanning calorimetry (DSC). Four kinds of anions with strong hydration, including CO32–, SO42–, S2O32–, and F, and four kinds of anions with weak hydration, including Br, NO3, I, and ClO4, and Cl as a medium anion are systematically studied and found to demonstrate the effects of the residual hydroxyl groups and network structure of PVF on the LCST values of PVF-g-PNIPAM hydrogels in comparison with that of neat PNIPAM. On the one hand, the existence of hydroxyl groups on PVF backbone promotes the solubility of grafted PNIPAM due to their hydrophilicity and hydrogen-bond interactions with water. On the other hand, the network structure of as-prepared samples restricts free movements of grafted PNIPAM chains, which results in the increase of LCST values. In addition, the difference of grafting percentage also influences the variation of LCST values of PVF-g-PNIPAM hydrogels under salt concentration.
Tailoring the Properties of Diels-Alder Reaction Crosslinked High-performance Thermosets by Different Bismaleimides
Kai-Ju Luo, Li-Bo Huang, Yan Wang, Jun-Rong Yu, Jing Zhu, Zu-Ming Hu
Corrected proof , doi: 10.1007/s10118-019-2328-7
[Abstract](329) [FullText HTML](145) [PDF 923KB](19)
A series of Diels-Alder reaction cross-linked thermosets with recyclability and healability were prepared from furan-containing aromatic polyamide and bismaleimides with different chemical structures. The structures of synthesized bismaleimides were confirmed by 1H nuclear magnetic resonance (1H-NMR) spectroscopy; their reversible cross-linking with the furanic polyamide was further detected by 1H-NMR technique and sol-gel transition behavior. The dynamic mechanical analysis and tensile test revealed the variable thermal and mechanical properties of thermosets cross-linked by different bismaleimides and with different molar ratios of maleimide group to furan group (Ima/fur). The tensile test also demonstrated that the better recyclability and solvent-assisted healability of thermosets cross-linked could be achieved by more flexible bismaleimides. This work is expected to provide valuable information for design of recyclable and healable high-performance thermosets with desired properties.
A new evaluation criterion for optimizing the mechanical properties of toughened polypropylene/silica nanocomposites
Hossein Pourrahmani, Mona Golparvar, Mohammad Fasihi
Accepted Manuscript , doi: 10.1007/s10118-020-2399-5
[Abstract](22) [PDF 2365KB](5)
This study aims to experiment with the mechanical properties of polypropylene (PP)/thermoplastic elastomer/nano-silica/compatibilizer nanocomposite using the melt mixing method. The addition of polyolefin elastomers has proved to be an approachable solution for low impact strength of PP, while it would also reduce the young modulus and tensile strength. That is why reinforcement would be applied to this combination to enhance the elastic modulus. The mechanical properties of the prepared composites were devised to train an artificial neural network to predict these properties of the system in 6256 unknown points. Therefore, the sensitivity analysis was performed and the share of each input parameters on the respective output values was calculated. Additionally, a novel parameter called Nanocomposite Evaluation Criterion (NEC) is introduced to analyze the suitability of the nanocomposites considering the mechanical properties. Accordingly, the formulation with optimal mechanical properties of toughness, elongation break, tensile strength, Young modulus, and impact strength was obtained.
Structures and Properties of Polyimide with Different Pre-imidization Degrees
Fuyao Hao, Jianhua Wang, Shengli Qi, Guofeng Tian, Dezhen Wu
Accepted Manuscript , doi: 10.1007/s10118-020-2407-9
[Abstract](2) [PDF 1666KB](0)
A series of polyimide (PI) films derived from pyromellitic dianhydride (PMDA) and 4,4- oxydianiline (ODA) were prepared with the employment of chemical pre-imidization, and the pre-imidization degree (pre-ID) was found influential on structures and properties of the films obtained. Specifically, a certain degree of chemical imidization could promote the in-plane orientation of molecular chains inside the film, which then enhanced the mechanical strength and reduced the coefficient of thermal expansion (CTE) of the films. Further, such pre-imidization process could expand the internal space gap inside the films, thereby lowering their dielectric constant and glass transition temperature. Our study provides a new approach for preparing high-performance PI films through chemical imidization.
Differences in crystallization behaviors between cyclic and linear polymer nanocomposites
Rongjuan Liu, Zhiping Zhou, Yong Liu, Zhaopeng Liang, Yongqiang Ming, Tongfan Hao, Yijing Nie
Accepted Manuscript , doi: 10.1007/s10118-020-2403-0
[Abstract](11) [PDF 1770KB](2)
Cyclic polymers exhibit fascinating crystallization behaviors owing to the absence of chain ends and more compact conformations. In the current simulation, dynamic Monte Carlo simulations were performed to reveal the underlying mechanism of the effect of chain topology and chain length on crystallization of polymer solutions containing one-dimensional nanofiller. Simulation results suggested that the filled cyclic polymers exhibit higher melting temperature, higher crystallization temperature and faster crystallization rate than the analogous linear polymers of identical chain length, especially in the systems with relatively shorter chains. Based on the Thomson-Gibbs Equation, we theoretically analyzed the difference in the melting point between the cyclic and linear polymers under different chain lengths, and derived the dependence of the ratio of the melting point of the linear polymers to that of its cyclic analogs on chain length. In addition, it was also observed that the nanofiller can induce the formation of nanohybrid shish-kebab structure during isothermal crystallization of all systems.
Highly stretchable and conductive hybrid fibers for high-performance fibrous electrodes and all-solid-state supercapacitors
Gui-Qing Wu, Xin-Yu Yang, Jia-Hui Li, Nan Sheng, Cheng-Yi Hou, Yao-Gang Li and Hong-Zhi Wang
Accepted Manuscript , doi: 10.1007/s10118-020-2381-2
[Abstract](28) [PDF 3393KB](1)
The development of lightweight, flexible, and stretchable energy storage systems is essential for state-of-the-art electronic devices. We propose a new and broad strategy to fabricate a stretchable and conductive GO/CNTs–TPU fiber electrode by direct wet spinning, from which a flexible fibrous supercapacitor is fabricated. The fibrous electrode exhibits a high strength of 11.68 MPa, high conductivity of 342 S/cm, and high specific capacitances (21.8 mF/cm, 36.45 F/cm3, and 95 F/g). The specific capacitance of the assembled all-solid-state hybrid fiber-shaped supercapacitor reaches 14.3 F/cm3. After 5000 charge–discharge cycles, 97% of the capacitance of the hybrid supercapacitor is maintained. These high-strength electrochemical electrode materials could be potential candidates for applications in practical and large-scale energy storage systems and textile clothes.
Better choice: linear long chains rather than branched ones to improve mechanical performance of polyethylene through generating shish-kebabs
Lufeng Deng, Xi-Xi Zhang, Dong Zhou, Jian-Hua Tang, Jun Lei, Jun-Fang Li and Zhong-Ming Li
Accepted Manuscript , doi: 10.1007/s10118-020-2397-7
[Abstract](23) [PDF 7855KB](1)
We utilized two structurally different long chains (linear and branched ultra-high molecular weight polyethylene) to reveal the dependence of flow-induced crystallization on long chain architecture, and prepared two bi-disperse systems of 98 wt% short chain and 2 wt% long chain. A flow field was applied to the bi-disperse polyethylene melt by a modified injection-molding machine, known as oscillation shear injection molding (OSIM). For the first time, the structural influence of long chains on flow-induced shish-kebab formation was systematically investigated. For the intermediate layer of OSIM samples, the branched long chains are better than the linear long chains at inducing shish-kebab formation, agreeing with the reported literatures, because the branches can maintain their oriented conformations longer. But unexpectedly, the reverse is the case for the core layer of OSIM samples, where the shear flow is much weaker than the intermediate layer. To understand the unexpected phenomenon, the lifetime of shishes induced by different long chains has been compared. Result demonstrates that the linear-induced shishes possessed higher thermal stability than the branched-induced ones so that the linear-induced shishes can survive in the core layer of OSIM samples. Additionally, unlike other methods for flow-induced crystallization, OSIM could create samples for measuring mechanical properties, and thus offer the chance to reveal the relationship between structure and performance. The mechanical results demonstrate that both long chains remarkably enhanced the mechanical properties because of the significant promoting effect of long chains and intense flow fields on shish-kebab formation. However, the linear long chains induced more stable and flawless shishes with higher tensile strength and modulus (80.4 and 1613.5 MPa, respectively) than the branched ones (74.4 and 1489.3 MPa). Our research not only helps elucidate the mechanism of shish-kebab formation but also provides a better choice to reinforce polymers by adding long chains with suitable structure.
An organic solvent-free approach towards PDI/carbon cloth composites as flexible lithium ion battery cathodes
Dongqing Wu, Deng Lu, Peng Yang, Lie Ma, Biao Jiang, Xin Xi, Fancheng Meng, Wenbei Zhang, Fan Zhang, Qianqian Zhong, Ruili Liu
Accepted Manuscript , doi: 10.1007/s10118-020-2388-8
[Abstract](41) [PDF 1738KB](2)
An acidic solution based method towards flexible lithium ion battery (LIB) cathodes is developed in this work with perylene diimide (PDI) as the electroactive component and carbon cloth (CC) as the current collector. In this approach, PDI is firstly dispersed in concentrated sulfuric acid (H2SO4) and then deposited on CC substrate after the dilution of H2SO4, which provides an organic solvent-free strategy to construct integrated LIB cathodes. The acdic solution based fabrication process also allows the facile adjusting the loading amounts of PDI in the cathodes, which can effectively influence the battery performances of the PDI/CC cathodes. As the result, the acidic solution processed PDI/CC cathode can deliver a high specific capacity of ~ 136 mAh g-1 at the current density of 50 mA g-1 in both half cell with lithium foil as anode and full cell with pre-lithiated CC as anode. In both types of the batteries, the PDI/CC cathodes show good cycling stabilities by retaining ~ 84 % of the initial capacities after 300 charge-discharge cycles at 500 mA g-1. Additionally, the excellent mechanical stability of the PDI/CC cathode enables the LIBs in pouch cell to maintain the electrochemical performances under various bending states, demonstrating their potentials for flexible LIBs.
Quinolinyl Imidazolidin-2-Imine Nickel Catalyzed Efficient Copolymerization of Norbornene with para-Chlorostyrene
Yanqing Li, Jian Zhou, Ru Xiao and Zhengguo Cai
Accepted Manuscript , doi: 10.1007/s10118-020-2400-3
[Abstract](22) [PDF 1008KB](5)
A series of novel quinolinyl imidazolidin-2-imine nickel complexes with different substituents on the imidazolin-2-imine ligand were synthesized and characterized. The complexes in the presence of methylaluminoxane (MAO) as a cocatalyst conducted the copolymerization of norbornene (N) and styrene (S) or para-chlorostyrene (CS) with high activity (up to 1070 kg·mol-1·h-1). The installation of sterically bulky substituents on the imidazolidine-2-imine ligand was effective for the increase of the molecular weight and the comonomer content, affording high molecular weight copolymers with tunable CS content (0.57-11.7 mol%), in which the existence of Cl group can provide reaction site for the further functionalization of copolymers as well as the synthesis of graft or cross-linked polymers. The linear relationship between the comonomer content and the glass transition temperature of the copolymers and the monomer reactivity ratios in the copolymerization indicated the formation of the expected functionalized cyclic olefin copolymers (COC).
Ionic Liquid/Poly(ionic liquid)-based Semi-solid State Electrolytes for Lithium-ion Batteries
Deng-Zhou Zhang, Yong-yuan Ren, Yin Hu, Liang Li, and Feng Yan
Accepted Manuscript , doi: 10.1007/s10118-020-2390-1
[Abstract](66) [PDF 1599KB](6)
Ionic liquids (ILs) have appeared as the most promising electrolytes for lithium-ion batteries, owing to their unique high ionic conductivity, chemical stability and thermal stability properties. Poly(ionic liquid)s (PILs) containing both IL-like characteristic and polymer structure are emerging as an alternative of traditional electrolyte. In this review, recent progress on the applications of IL/PIL-based semi-solid state electrolytes, including gel electrolytes, ionic plastic crystal electrolytes, hybrid electrolytes and single-ion conducting electrolytes for lithium-ion batteries are discussed.
Polyphosphoester-Modified Cellulose Nanocrystals for Stabilizing Pickering Emulsion Polymerization of Styrene
Kun-Ming Che, Ming-Zu Zhang, Jin-Lin He, Pei-Hong Ni
Accepted Manuscript , doi: 10.1007/s10118-020-2404-z
[Abstract](13) [PDF 2009KB](6)
The structure and properties of functional nanoparticles are important for stabilizing Pickering emulsion polymerization. Recently, cellulose nanocrystals (CNCs) are increasingly favored as a bio-based stabilizer for Pickering emulsions. In this study, we reported a novel functionalized polyphosphoester-grafted CNCs for the stabilization of oil-in-water Pickering emulsions and the emulsion polymerization of styrene. First, polyphosphoester containing an amino at one end of the chain, abbreviated as PBYP-NH2, was prepared by ring-opening polymerization (ROP) and hydrolysis reaction, wherein PBYP represents poly[2-(but-3-yn-1-yloxy)-2-oxo-1,3,2- dioxaphospholane]. Subsequently, CNC-COOH was obtained via 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation of CNCs. The functionalized nanocrystals CNC-PBYP-COOH with carboxyl groups and polyphosphoester on the surface were obtained by the reaction of PBYP-NH2 with CNC-COOH. Finally, we used CNC-PBYP-COOH as sole particle emulsifiers to stabilize styrene-in-water Pickering emulsions and studied its effects on the emulsions in details by using dynamic light scattering (DLS). The results indicated that the properties of these emulsions depended on the concentration of hydrophobically modified CNCs, volume ratios of oil to water and pH values. The modified CNCs had higher ability to stabilize the styrene-in-water emulsions relatived to the unmodified CNCs, and a stable oil-in-water (o/w) Pickering emulsion with diameter of hundreds of nanometers could be obtained. The resulting emulsions could be polymerized to yield nanosized latexes. The polyphosphoester-modified CNCs as green particle emulsifiers can efficiently stabilize nanoemulsions and latexes, which would promote the development of novel environmentally friendly materials.
Fiber-Shaped Supercapacitors: Advanced Strategies toward High-Performances and Multi-Functions
Jie Yang, Xue-Lian Li, Jing-Wen Zhou, Bin Wang, Jian-Li Cheng
Accepted Manuscript , doi: 10.1007/s10118-020-2389-7
[Abstract](36) [PDF 5041KB](5)
Fiber-shaped supercapacitors (FSSCs) show great potential in portable and wearable electronics due to their unique advantages of high safety, environmental friendliness, high performances, outstanding flexibility and integrability. They can directly act as the power sources or be easily integrated with other flexible devices to constitute self-powered and sustainable energy suppliers, providing excellent adaptability to irregular surfaces. This review mainly summarize the recently reported works of FSSCs including preparation methods of various fiber electrodes, construction strategies of FSSCs and multi-functional device integrations, exploration of reaction mechanisms and strategies to improve the electrochemical performance and provision of suggestions on further designing and optimization of FSSCs. Meanwhile, it shared our perspectives on challenges and opportunities in this field, shedding light on the development of high-performance fiber-shaped supercapacitors with multi-functions.
Revisiting Silica Networks by Small-Angle Neutron Scattering and Synchrotron Radiation X-ray Imaging Techniques
Xin-Wei Kang, Dong Liu, Ping Zhang, Ming Kang, Feng Chen, Qing-Xi Yuan, Xiu-Li Zhao, Ying-Ze Song, and Li-Xian Song
Accepted Manuscript , doi: 10.1007/s10118-020-2402-1
[Abstract](69) [PDF 1786KB](4)
The silicone rubber composites present remarkable mechanical properties due to the double network structure constructed with molecular network of matrix and filler structure of silica. Nevertheless, the filler network structure and corresponding reinforcement mechanism are still under debate and need to be further probed with the aid of applicative advanced analysis techniques. Herein, small-angle neutron scattering (SANS) and synchrotron radiation X-ray nano-computed tomography (Nano-CT) techniques are employed to explore the evolution of filler networks of fumed, precipitated and sol-gel silica, respectively. Our studying results reveal the formation of filler network constructed by the interconnecting of branched silica aggregates. And the silica with high structure, pertaining to amorphous morphology, small size and large surface area presents short distance and effective molecular chain bridge between aggregates, thus forming strong and steady filler networks. This work would provide deep-seated revisiting of filler networks and corresponding reinforcement mechanism and offer guidance for optimizing the mechanical properties of silicone rubber.
Preparation of Titanium-silphenylene-siloxane Hybrid Polymers with High Refractive Index, Transmittance, and Thermal Stability
Dong Zhao, Shu-xi Shan, Meng Zhang, Xiao-a Zhang, Sheng-ling Jiang, and Ya-fei Lyu
Accepted Manuscript , doi: 10.1007/s10118-020-2398-6
[Abstract](25) [PDF 1430KB](3)
Vinyl-containing titanium-silphenylene-siloxane oligomers (O1, O2, O3, and O4) with different molar ration of titanium to silicon were successfully synthesized in high yields by nonhydrolytic sol-gel reaction, and the obtained four oligomers were further crosslinked with methylphenyl hydro-silicone oil (4) to form corresponding polymers (P1, P2, P3, and P4) by hydrosilylation reaction. Their structures have been characterized with spectroscopic characterization techniques including FT-IR, 1H NMR, and Raman spectroscopy. The effect of titanium element on crosslinking behavior, thermal resistance, refractive index, transparency, thermal aging stability, glass transition temperature and surface properties of the polymers were studied. Compared with titanium-free polymer P1, the thermal resistance, refractive index, and thermal aging stability of titanium-silphenylene-siloxane polymers (P2, P3, and P4) were significantly improved. The titanium-silphenylene-siloxane polymers achieve a high refractive index (n=1.580-1.584) and thermostability (T5d>500 oC). In thermal aging, the polymers exhibited superior performances with high optical transparency (~90% at 450 nm) and exhibited high thermal stability (~84% at 450 nm after thermal aging at 150 oC for 120 hours). These data indicate that the polymers have potential application in optical materials such as LED encapsulants.
Soluble Polyimide-reinforced TGDDM and DGEBA Epoxy Composites
Qi Chen, Shun Wang, Feng Qin, Kuan Liu, Qian Liu, Qing Zhao, Xingyi Wang, and Yanhong Hu
Accepted Manuscript , doi: 10.1007/s10118-020-2395-9
[Abstract](18) [PDF 1802KB](0)
Polyimide (PI) synthesized from aromatic diamine and dianhydrides via two-step poly-condensation method was highly soluble in TGDDM (MY-720) and DGEBA (E-51) at desirable temperature. TGDDM-PI (M-PI) and DGEBA-PI (E-PI) composites within 0.5 ~ 3% PI loading could be prepared without organic solvent. On the cryogenically fractured surfaces of M-PI and E-PI composites, no obvious heterogeneous phase was observed by SEM. The mechanical properties were promoted significantly by PI, especially for impact strength. Adding 2% PI-2W into MY-720 and E-51 composites, the impact strength increases to 21 and 51 kJ/m2; the tensile strength increases by 62% and 19%, and the flexural strength, 18% and 13%, with slight increases in tensile modulus. These results were related to the promotion in plasticity of composites and changes in fragile→ductile fracture mode. Moreover, Tg and thermal stability of M-PI and E-PI were increased effectively.
An Overview of Stretchable Supercapacitors Based on Carbon Nanotube and Graphene
Wenle Ma, Zhihao Cai, Yi Zhang, Ziyuan Wang, Lun Xia, Suping Ma, Guanghao Li, Yi Huang
Accepted Manuscript , doi: 10.1007/s10118-020-2386-x
[Abstract](31) [PDF 6515KB](3)
The wearable demand of modern electronic devices makes flexible and stretchable energy storage device urgently needed. Stretchable and flexible supercapacitors (SCs) are energy storage devices that provide ultrahigh power density while have long-term durability, high security, and electrochemical stability. Among different SCs electrode materials, CNTs and graphene-based materials exhibit great potential in terms of stretchable SCs due to its ultrahigh electrical conductivity, large specific surface area and good mechanical properties. In this review, the state-of-the-art process and achievements in the field of stretchable SCs enabled by CNTs and graphene are presented, which include of the novel design strategy, mechanical and electrochemical properties. The final section highlights current challenges and future perspectives on research in this thriving field.
Investigation on self-healing property of epoxy resins based on disulfide dynamic links
Zijian Li, Jiang Zhong, Maochen Liu, Jinchuang Rong, Kun Yang, Jiyong Zhou, Liang Shen, Fei Gao, Haifeng He
Accepted Manuscript , doi: 10.1007/s10118-020-2406-x
[Abstract](12) [PDF 1556KB](1)
Self-healing polymers based on dynamic crosslinkers have drawn rapidly increasing interest over the last decade. Here, a self-healable epoxy network with exchangeable disulfide bonds was synthesized by polymerizing two epoxies with an aromatic amine containing a disulfide bond. The bisphenol a diglycidyl ether (DGEBA) and poly (ethylene glycol) diglycidyl ether (DER736) were used as rigid and soft components, respectively. The crosslink densities of studied polymers decreased with the increasing amount of DER736, resulting in the lower glassy temperature and weaker mechanical strength. The dynamic covalent network character of disulfide bond and its low active energy were also investigated through stress relaxation experiments at various temperatures. The self-healing performance of healable epoxy resins with varied flexibility was measured by tensile tests. The tensile strength of a full-cut sample was restored to 84 % (13 MPa) of the initial values (16 MPa) at moderate temperature. Its healed fracture strain was up to 505 %. Moreover, the effect of healing time and temperature on the self-healing properties was also studied. A model was proposed to investigate the self-repairing efficiency evolution with healing time, suggesting that hydrogen bonds mainly contributed to the initial sticking or interfacial adhesion, the disulfide links and chain interdiffusion assisted time dependent reformation of networks to restore the original mechanical strength.
Sustainable blends of poly (propylene carbonate) and stereocomplex polylactide with enhanced rheological properties and heat resistance
Yi Li, Yan-Cun Yu, Chang-Yu Han, Xian-Hong Wang and De-Xin Huang
Accepted Manuscript , doi: 10.1007/s10118-020-2408-8
[Abstract](0) [PDF 926KB](0)
Sustainable blends of poly (propylene carbonate) (PPC) and stereocomplex polylactide (sc-PLA) were prepared by melt blending equimolar poly(L-lactic acid) (PLLA) and poly(D-lactide acid) (PDLA) with PPC to form sc-PLA crystals in situ during melt blending process. Differential scanning calorimetry analysis revealed that only sc-PLA, no homo-crystallization of PLLA or PDLA formed in the PPC matrix as the sc-PLA content was more than 10 wt%. Very intriguingly, scanning electronic microscopy observation showed that sc-PLA was evenly dispersed in the PPC phase as spherical particles and the sizes of sc-PLA particles did not obviously increase with increasing sc-PLA content. As a consequence, the rheological properties of PPC were greatly improved by incorporation of sc-PLA. When the sc-PLA content was 20 wt%, a percolation network structure was formed, and the blends showed solid-like behavior. The sc-PLA particles could reinforce the PPC matrix, especially at a temperature above the glass transition temperature of PPC. Moreover, the vicat softening temperature of PPC/sc-PLA blends could be increased compared with that of pure PPC.
Infusing high-density polyethylene with graphene-zinc oxide to produce antibacterial nanocomposites with improved properties
Youli Yao, Manuel Reyes De Guzman, Hong Duan, Chen Gao, Xu Lin, Yihua Wen, Juan Du, Li Lin, Jui-Chin Chen, Chin-San Wu, Maw-Cherng Suen, Yali Sun, Wei-Song Hung, and Chi-Hui Tsou
Accepted Manuscript , doi: 10.1007/s10118-020-2392-z
[Abstract](37) [PDF 2196KB](5)
Nanocomposites of high-density polyethylene (HDPE) modified with 0.2 phr graphene-zinc oxide (GN-ZnO) exhibited optimal mechanical properties and thermal stability. Two other nano-materials—GN and nano-ZnO—were also used to compare them with GN-ZnO. Increasing the content of GN-ZnO gradually enhanced the antibacterial and barrier properties, but the addition of 0.3 phr GN-ZnO led to agglomeration that caused defects in the nanocomposites. Herein, we investigated the antibacterial and barrier properties of HDPE nanocomposites infused with different nanoparticles (GN, ZnO, GN-ZnO) of varying concentrations. HDPE and the nanoparticles were melt-blended together in a Haake-Buchler Rheomixer to produce a new environment-friendly nano-material with improved physical and chemical properties. The following characterizations were conducted: tensile test, thermogravimetric analysis, morphology, differential scanning calorimetry, X-ray diffraction, antibacterial test, and oxygen and water vapor permeation test. The results showed that the crystallinity of HDPE was affected with the addition of GN-ZnO, and the nanocomposites had effective antibacterial capacity, strong mechanical properties, high thermal stability, and excellent barrier performance. This type of HDPE nanocomposites reinforced with GN-ZnO would be attractive for packaging industries.
COFs based Porous Material for Photocatalytic Applications
Xun-Liang Hu, He-Guo Li, Bi-En Tan
Accepted Manuscript , doi: 10.1007/s10118-020-2394-x
[Abstract](27) [PDF 1148KB](1)
Covalent organic frameworks(COFs) are an emerging class of photoactive material, solely composed of light elements. Owing to their ordered structure, crystallinity and high porosity led to enormous worldwide attention in many research fields. The extensive π-electron conjugation, light-harvesting and charge transport characteristics make them a fascinating polymer for photocatalytic systems. Versatile selection of building blocks and innumerable synthetic methodologies make it a robust platform for solar energy production. In this mini-review, we summarized recent progress and challenges of the design, construction, and applications of COFs-based photocatalysts, and also presented some perspectives on challenges.
Natural Biopolymers for Flexible Sensing and Energy Devices
Muqiang Jian, Yingying Zhang, Zhongfan Liu
Accepted Manuscript , doi: 10.1007/s10118-020-2379-9
[Abstract](74) [PDF 9264KB](4)
Natural biopolymers feature natural abundance, devise chemical compositions, tunable properties, easy processability, excellent biocompatibility and biodegradability, as well as nontoxicity, providing new opportunities for the development of flexible sensing and energy devices. Generally, biopolymers are utilized as the passive and active building blocks to endow the flexible devices with mechanical robustness and good biocompatibility. This review aims to provide a comprehensive review on natural biopolymer-based sensing and energy devices. The diverse structures and fabrication processes of three typical biopolymers, including silk, cellulose and chitin/chitosan, are presented. We review their utilities as the supporting substrates/matrix, active middle layers, separators, electrolytes, and active components of flexible sensing devices (sensors, actuators, transistors) and energy devices (batteries, supercapacitors, triboelectric nanogenerators). Finally, the remaining challenges and future research opportunities are discussed.
An azoester-containing photoresponsive linear liquid crystal polymer with good mesophase stability
Shu-Qiang Han, Ying-Ying Chen, Bo Xu, Jia Wei and Yan-Lei Yu
Accepted Manuscript , doi: 10.1007/s10118-020-2383-0
[Abstract](64) [PDF 3813KB](3)
Photoresponsive linear liquid crystal polymers (LLCPs) are attractive because of the excellent stimuli-responsibility and the good processability. In this study, a new photoresponsive LLCP containing azoester (PC11AE6) with good mesophase stability was synthesized by ring-opening metathesis polymerization. By introducing photoresponsive azoester mesogenic unit, which has high rigidity and large length-diameter ratio, the resultant polymer possesses a broad mesophase temperature interval (isotropic temperature = 180 °C). The study on mesophase by 2D-wide angle X-ray diffraction indicated that the mesogens orientated spontaneously into smectic A phase after annealing. The orientated films and fibres exhibited macroscopic, rapid and reversible deformations under irradiation as a result of the photoisomerization of azoester as confirmed by UV-vis absorption spectrophotometer. We anticipate that this work provides a strategy for preparing linear liquid crystal polymer with a broad mesophase temperature range, which is positive for potential applications.
Design and Properties of Fluoroelastomer Composites via Incorporation of MWCNTs with Varies Modification
Guangyao Yang, Lifen Tong, and Xiaobo Liu
Accepted Manuscript , doi: 10.1007/s10118-020-2405-y
[Abstract](3) [PDF 3333KB](0)
MWCNTs modified with silane coupling agent A-1120 (MWCNTs-A1120) were prepared. Compared with the raw MWCNTs, acidified MWCNTs (MWCNTs-COOH) and MWCNTs grafted with EDA (MWCNTs-NH2), MWCNTs-A1120 have the best dispersion in fluoroelastomer at the same doping ratio. Therefore, fluoroelastomer/MWCNTs-A1120 composite has the best mechanical properties with tensile strength of 13.92 MPa, elongation at break of 111.78%. Then, the effects of doping amount of MWCNTs-A1120 on the electrical properties of the composites were investigated. The dielectric constant of the composite increases with the increase of MWCNTs-A1120, and the dielectric loss does not change much. When the doping amount of the MWCNTs-A1120 is 5 wt%, the dielectric constant and the dielectric loss value are greatly increased, and the volume resistivity is greatly decreased, which proves that the conductive network is formed in the composite, so the filling amount of 5 wt% is the percolation threshold. The tensile deformation of the sample also affects the electrical properties of the composites. As the tensile deformation increases, the dielectric constant and dielectric loss of the composite decrease. For the composite with 5 wt% MWCNTs-A1120, excessive tensile deformation will destroy the conductive network structure of the composite, so the composite will change from conductive material to dielectric material. Therefore, such composite is a good candidate for flexible conductive material or flexible dielectric material used in harsh environments such as high temperatures and various aggressive solvents.
Effects of Branching Strategy on the Gene Transfection of Highly Branched Poly(β-amino ester)s
Yao Wang, Chenfei Wang, Ming Li, Dezhong Zhou, Wei Huang, Wenxin Wang, Deyue Yan
Accepted Manuscript , doi: 10.1007/s10118-020-2393-y
[Abstract](27) [PDF 3350KB](3)
Highly branched poly(β-amino ester)s (HPAEs) have emerged as one type of the most viable non-viral gene delivery vectors, both in vitro and in vivo. However, the effects of different branching strategies on the gene transfection performance have not yet been explored. Here, using triacrylate (B3) and diamine (B4) as the branching monomers, a series of HPAEs were synthesized via the “A2+B3+C2” and “A2+B4+C2” strategies, respectively. Results show that the branching strategy plays a pivotal role in dictating the physiological properties of the HPAE/DNA polyplexes and thus leading to obviously different cell viability and transfection efficiency. Comparatively, HPAEs synthesized via the “A2+B3+C2” branching strategy are more favorable for DNA transfection than that synthesized via the “A2+B4+C2” strategy. This study may provide new insights into the development of HPAEs based non-viral DNA delivery system.
Thermally Conductive and Insulating Epoxy Composites by Synchronously Incorporating Si-sol Functionalized Glass Fibers and BN Fillers
Ruihan Zhang, Xuetao Shi, Lin Tang, Zheng Liu, Junliang Zhang, Yongqiang Guo, Junwei Gu
Accepted Manuscript , doi: 10.1007/s10118-020-2391-0
[Abstract](54) [PDF 5862KB](0)
Glass fibers (GFs)/epoxy laminated composites always present weak interlaminar shear strength (ILSS) and low cross-plane thermal conductivity coefficient (λ┴). In this work, silica-sol, synthesized from tetraethyl orthosilicate (TEOS) and KH-560 via sol-gel method, was performed to functionalize the surface of GFs (Si-GFs). And the thermally conductive BNN-30/Si-GFs/epoxy laminated composites were then fabricated. Results demonstrate that Si-sol is beneficial to the improvement of mechanical properties for epoxy laminated composites (especially for ILSS). The obtained BNN-30/Si-GFs/epoxy laminated composites with 15 wt% BNN-30 fillers display the optimal comprehensive properties. In-plane λ (λ//) and λ┴ are the maximum of 2.37 and 1.07 W m-1K-1, 146.9% and 132.6% higher than those of Si-GFs/epoxy laminated composites (λ//=0.96 W m-1K-1 and λ┴=0.46 W m-1K-1), respectively, and also about 10.8 and 4.9 times those of pure epoxy resin (λ//=λ┴, 0.22W m-1K-1). And the heat-resistance index (THRI), dielectric constant (ε), dielectric loss (tanδ), breakdown strength (E0), surface resistivity (ρs) as well as volume resistivity (ρv) are 197.3oC, 4.95, 0.046, 22.3 kV mm-1, 1.8×1014 Ω, and 2.1×1014 Ω·cm, respectively.
Surface Patterning of Self-healing p(MMA/nBA) Copolymer for Dynamic Control Cell Behaviors
Su-su Liu, Ze-hong Xiang, Zhi-fang Ma, Xue-wen Wu, Qiang Shi, Shing-Chung Wong, and Jing-hua Yin
Accepted Manuscript , doi: 10.1007/s10118-020-2382-1
[Abstract](57) [PDF 1410KB](5)
Cell behaviors are regulated by a dynamic and complex environment characterized by biophysical, mechanical and biochemical properties. However, most works regulate cell behaviors under static conditions or by external factors. To control cell adhesion and proliferation with a dynamic and mechanical environment, we pattern the surface on self-healing copolymer p(MMA/nBA). The copolymer p(MMA/nBA) with the composition of 48/52 (MMA/nBA) recovers nearly 100% of its original tensile strains after 86 h recovery from deformation. The physical patterns on p(MMA/nBA) film are obtained over large areas and the size of the hole and the width of connecting bar are in line with the copper grid specifications. The patterned surface tends to be flat after 12 h with almost 75~80% recovery. Compared with cell incubation on polystyrene flat and patterned surface of p(MMA/nBA) film without self-healing capability, the number and morphology of cells are well manipulated on the patterned surface of self-healing p(MMA/nBA) film. This approach provides a convenient method to dynamically regulate the cell behaviors on the surface of self-healing materials without chemical or biological modifications.
Waste Tire Rubber-Based Refrigerants for Solid-State Cooling Devices
Nicolau Molina Bom, Érik Oda Usuda, Mariana da Silva Gigliotti, Denílson José Marcolino de Aguiar, William Imamura, Lucas Soares Paixão, and Alexandre Magnus Gomes Carvalho
Accepted Manuscript , doi: 10.1007/s10118-020-2385-y
[Abstract](114) [PDF 1286KB](19)
Management of discarded tires is a compelling environmental issue worldwide. Although there are several approaches developed to recycle waste tire rubbers, their application in solid-state cooling is still unexplored. Considering the high barocaloric potential verified for elastomers, the use of waste tire rubber (WTR) as a refrigerant in solid-state cooling devices is very promising. Herein, we investigated the barocaloric effects in WTR and polymer blends made of vulcanized natural rubber (VNR) and WTR, to evaluate its feasibility for solid-state cooling technologies. The adiabatic temperature changes and the isothermal entropy changes reach giant values, as well as the performance parameters, being comparable or even better than most barocaloric materials in literature. Moreover, pure WTR and WTR-based samples also present a faster thermal exchange than VNR, consisting of an additional advantage of using these discarded materials. Thus, the present findings evidence the encouraging perspectives of employing waste rubbers in solid-state cooling based on barocaloric effects, contributing to both the recycling of polymers and the sustainable energy technology field.
PEDOT: Fundamentals and Its Nanocomposites for Energy Storage
Hongwu Chen and Chun Li
Accepted Manuscript , doi: 10.1007/s10118-020-2373-2
[Abstract](94) [PDF 1919KB](10)
PEDOT, or poly(3,4-ethylenedioxythiophene), is among the most successful conducting polymer products because of its stable conductivity, colloidal processability and rich assembly behavior. Since the very first patents on PEDOT filed in 1988, the material has been widely explored for decades in many applications. In this review, a comprehensive summary on the synthesis, processing and post-treatment of PEDOT will be presented for the sake of the discussion on PEDOT and its nanocomposites for energy storage. Knowing what PEDOT lend itself to the electrode materials is of importance to the rational design of energy storage devices that maximize the real-world performance. Based on these discussions, a roadmap for the development of PEDOT as promising multifunctional electrode component is presented.
Three-dimensional Covalent Organic Frameworks as Host Materials for Lithium–Sulfur Batteries
Zhen Li, Hang-Yu Zhou, Fulai Zhao, Tian-Xiong Wang, Xuesong Ding, Bao-Hang Han, Wei Feng
Accepted Manuscript , doi: 10.1007/s10118-020-2384-z
[Abstract](50) [PDF 1932KB](6)
Two reported three-dimensional covalent organic frameworks (3D-COFs), COF-300 and COF-301, which have hierarchical porous structures and large pore volumes, were synthesized and employed as host materials for lithium–sulfur batteries. Owing to possessing excellent porosities as well as abundant hydroxyl groups in the pore walls, COF-301 can not only trap lithium polysulfides (PSs) via physical adsorption inside the pores, but also capture PSs by chemical interactions to relieve the shuttle effect. Interestingly, it’s the first time, 3D-COFs were utilized as host materials for lithium–sulfur batteries as well as hydroxyl groups were introduced into COFs for improving the battery performance. As a result, COF-301@S as cathode material can reserve the capacity of 411.6 mA h g–1 after 500 cycles with only 0.081% fading per cycle at 0.5 C, which exhibits better battery performance of COF-301@S compared with COF-300@S. This study not only expands the applications of 3D-COFs but also provides a new route for designing lithium–sulfur batteries.
A Self-assembled Nanoparticle Platform Based on Amphiphilic Oleanolic Acid Polyprodrug for Cancer Therapy
Ying-Sa Wang, Gui-Liang Li, Shang-Bin Zhu, Fan-Chen Jing, Run-Dong Liu, Sai-Sai Li, Jing He, Jian-Du Lei
Accepted Manuscript , doi: 10.1007/s10118-020-2401-2
[Abstract](19) [PDF 2435KB](4)
Oleanolic acid (OA) is a pentacyclic triterpenoid compound with extensive biological effects, such as anti-inflammatory and anticancer activities. However the application of OA in chemotherapy is hampered by its poor solubility and severe adverse effects. To solve the problems, we developed a self-assembled nanoparticle platform based on amphiphilic oleanolic acid polyprodrug, poly[oligo(ethylene glycol) methyl ether methacrylate]-b-poly[oleanolic acid methacrylate] (POEGMA-b-POAMA), encapsulating 10-hydroxycamptothecin (HCPT) to achieve efficient cancer therapy. The polyprodrug was prepared via reversible addition-fragmentation chain transfer polymerization (RAFT), and could self-assemble to prepare POEGMA-b-POAMA/HCPT nanoparticles (NPs). The obtained nanoparticles exhibited appropriate particle size, excellent drug stability, good drug loading capacity and high drug loading efficiency. In vitro drug release indicated that the drug release was prolonged to 132 h. The POEGMA-b-POAMA/HCPT NPs enhanced cell cytotoxicity in 4T1 cells and MCF-7 cells and could be efficiently uptaken by 4T1 cells. Furthermore, in vivo antitumor efficiency showed that the POEGMA-b-POAMA/HCPT NPs had great antitumor efficiency with considerably low adverse effects in the treatment of the 4T1 mouse breast tumor xenograft tumor. Therefore, POEGMA-b-POAMA/HCPT NPs provide great potential as a platform for drug delivery applications.
A high energy density self-supported and bendable organic electrode for redox supercapacitors with a wide voltage window
Rashid Iqbal, Aziz Ahmad, Lijuan Mao, Zahid Ali Ghazi, Abolhassan Imani, Chunxiang Lu, Lijing Xie, Saad Melhi, Fangyuan Su, Cheng-Meng Chen, Linjie Zhi and Zhixiang Wei
Accepted Manuscript , doi: 10.1007/s10118-020-2378-x
[Abstract](144) [PDF 1854KB](26)
Redox-active organic electrode materials are highly desirable in realizing next-generation all-in-one bendable electronic systems. Herein, a novel flexible supercapacitors (SCs) electrode is fabricated from poly(anthraquinonyl sulfide) (PAQS) and single-walled carbon nanotubes (SWCNTs) suspension by a simple vacuum filtration and named as PAQS-SWCNTs. The PAQS-SWCNTs electrode offered an initial capacitance of 223 F g-1 and outstanding capacitance retention up to 78.4% after 30,000 charge-discharge cycles at 0.5 A g-1 current density. In a high potential range (0-3 V) and aprotic electrolyte, the PAQS-SWCNTs electrodes in coin cell exhibited an outstanding energy density of 69 Wh kg-1 at a power density of 90.6 W kg-1, whereas in the fabricated flexible SCs it retained 63.2 Wh kg-1. The PAQSSWCNTs electrodes also showed extraordinary performance at a higher current density (20 A g-1) and maintained a specific capacitance of 55 F g-1 and 47 F g-1 for coin and flexible SCs, respectively. Moreover, the flexible SC is further verified to be able to illuminate up multiple LEDs. These futuristic findings showed that the SCs assembled with flexible PAQS-SWCNTs electrodes have potential application in energy-storage devices and make them highly appealing for future redox supercapacitors.
Translocation of heterogeneous flexible polymers assisted by binding particles
Wan-Cheng Yu
Accepted Manuscript , doi: 10.1007/s10118-020-2387-9
[Abstract](31) [PDF 823KB](3)
A polymer chain usually contains two or more types of monomeric species from the perspective of polymer chemistry, which poses a challenge to the understanding of structure-property relationships. It is of course true in the field of polymer translocation. In the present work I investigate the translocation dynamics of heterogeneous flexible polymers composed of two types of monomers labeled A and B through a nanopore assisted by binding particles (BPs) by using the coarse-grained Langevin dynamics simulations in two-dimensional domains. Specifically, multiblock copolymers with different block lengths and monomeric components are considered. I critically examine how the translocation dynamics responds to the variations in the block length and the monomeric content. Interestingly, it is found that the periodic structure of a multiblock copolymer causes an obvious fingerprint feature in the residence time of individual monomers in which the number of peaks is exactly equal to the number of blocks. These findings provide a basic understanding about the sequence-dynamics relationship for the BPs-assisted translocation of heterogeneous flexible polymers.

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2020, 38(2) .  
[Abstract](477) [PDF 30851KB](0)
Copolymerization of Azobenzene-bearing Monomer and 3,4-Ethylenedioxythiophene (EDOT): Improved Electrochemical Performance for Electrochromic Device Applications
Serife O. Hacioglu
2020, 38(2): 109 -117.   doi: 10.1007/s10118-019-2306-0
[Abstract](482) [FullText HTML](152) [PDF 983KB](14)
In this study, novel electrochromic copolymers of 3,4-ethylenedioxythiophene (EDOT) and (E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene (M1) with different monomer feed ratios were designed and synthesized electrochemically. Electrochemical and spectroelectrochemical characterizations were performed using voltammetry and UV-Vis-NIR spectrophotometry techniques to test the applicability of copolymers for electrochromic applications. In terms of electrochemical behaviors, addition of an electron-rich EDOT unit into the azobenzene-containing copolymer increased the electron density on the polymer chain and afforded copolymers with very low oxidation potentials at around 0.30 V. While the homopolymers (P1 and PEDOT) exhibited neutral state absorptions centered at 510 and 583 nm, EDOT-bearing copolymers showed red shifted absorptions compared to those of P1 with narrower optical band gaps. In addition, the poor optical contrast and switching times of azobenzene-bearing homopolymer were significantly improved with EDOT addition into the copolymer chain. As a result of the promising electrochromic and kinetic preperties, CoP1.5-bearing single layer electrochromic device that works between purple and light greenish blue colors was constructed and characterized.
Dendronized Polymers with High FTC-chromophore Loading Density: Large Second-order Nonlinear Optical Effects, Good Temporal and Thermal Stability
Meng Jin, Zhao-Chen Zhu, Qiu-Yan Liao, Qian-Qian Li, Zhen Li
2020, 38(2): 118 -125.   doi: 10.1007/s10118-019-2307-z
[Abstract](371) [FullText HTML](64) [PDF 414KB](24)
In this study, two new dendronized nonlinear optical (NLO) polymers were synthesized with high FTC chromophore loading density by introduction of high generation chromophore dendrons on the side chains. Due to their suitable molecular weights, both of them possessed good solubility in common solvents. They also inherited the advantages of dendrimers (large NLO coefficient), especially for PG2 whose NLO coefficient d33 value was as high as 282 pm·V–1. Also, PG2 had a good temporal stability with 80% of its maximum value being retained at the temperature as high as 129 °C.
Mediating the Migration of Mesenchymal Stem Cells by Dynamically Changing the Density of Cell-selective Peptides Immobilized on β-Cyclodextrin-modified Cell-resisting Polymer Brushes
Wang Du, De-Teng Zhang, Xue-Mei Wang, Tan-Chen Ren, Chang-You Gao
2020, 38(2): 126 -136.   doi: 10.1007/s10118-019-2324-y
[Abstract](432) [FullText HTML](266) [PDF 1011KB](4)
Dynamic control of mesenchymal stem cell (MSC) behaviors on biomaterial surface is critically involved in regulating the cell fate and tissue regeneration. Herein, a stimuli-responsive surface based on host-guest interaction with cell selectivity was developed to regulate migration of MSCs in situ by dynamic display of cell-specific peptides. Azobenzene-grafted MSC-affinitive peptides (EPLQLKM, Azo-E7) were grafted to β-cyclodextran (β-CD)-modified poly(2-hydroxyethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (PHG) brushes, which were prepared by using surface-initiated atom transfer radical polymerization (SI-ATRP). X-ray photoelectron spectroscopy (XPS), quartz crystal microbalance (QCM), and water contact angle were used to characterize their structure and property. Cell adhesion assay showed that the combination effect of resisting property of PHG and MSC-affinity of E7 could promote the selective adhesion of MSCs over other types of cells such as RAW264.7 macrophages and NIH3T3 fibroblasts to some extent. UV-Vis spectroscopy proved that the competing guest molecules, amantadine hydrochloride (Ama), could release Azo-E7 peptides from the CD surface to different extents, and the effect was enhanced when UV irradiation was employed simultaneously. As a result, the decrease of cell adhesion density and migration rate could be achieved in situ. The cell density and migration rate could be reduced by over 40% by adding 20 μmol/L Ama, suggesting that this type of surface is a new platform for dynamic regulation of stem cell behaviors in situ.
Photo-grafting Poly(acrylic acid) onto Poly(lactic acid) Chains in Solution
Jia-Xing Wang, Yan-Bin Huang, Wan-Tai Yang
2020, 38(2): 137 -142.   doi: 10.1007/s10118-019-2308-y
[Abstract](487) [FullText HTML](155) [PDF 319KB](19)
Poly(lactic acid) (PLA) is one of the most important bio-plastics, and chemical modification of the already-polymerized poly(lactic acid) chains may enable optimization of its material properties and expand its application areas. In this study, we demonstrated that poly(lactic acid) can be readily dissolved in acrylic acid at room temperature, and acrylic acid can be graft-polymerized onto poly(lactic acid) chains in solution with the help of photoinitiator benzophenone under 254 nm ultraviolet (UV) irradiation. Similar photo-grafting polymerization of acrylic acid (PAA) has only been studied before in the surface modification of polymer films. The graft ratio could be controlled by various reaction parameters, including irradiation time, benzophenone content, and monomer/polymer ratios. This photo-grafting reaction resulted in high graft ratio (graft ratio PAA/PLA up to 180%) without formation of homopolymers of acrylic acid. When the PAA/PLA graft ratio was higher than 100%, the resulting PLA-g-PAA polymer was found dispersible in water. The pros and cons of the photo-grafting reaction were also discussed.
Cross-linked Polyamides Prepared through Direct Bulk Michael Addition and Polycondensation from 1,6-Hexanediamine and Methyl Acrylate
Sheng-Qing Yang, Jin-Nan Zhao, Jing-Bo Zhao, Zhi-Yuan Zhang, Jun-Ying Zhang
2020, 38(2): 143 -150.   doi: 10.1007/s10118-019-2332-y
[Abstract](349) [FullText HTML](138) [PDF 725KB](8)
Cross-linked polyamides (cPAs) were prepared through direct bulk Michael addition and subsequent polycondensation. Several mixed hexanediamine multi-esters (HDAMEs) were generated through the Michael addition of 1,6-hexanediamine (HDA) and methyl acrylate (MA) at 50 °C with different HDA/MA molar ratios. Melt polycondensation of HDAMEs then proceeded at 150 or 170 °C in flasks to obtain viscous fluids, and curing was continued in tetrafluoroethylene molds to obtain cPA films. The Michael addition was monitored on the basis of FTIR and ESI-MS spectra. The cPA films were characterized by DSC, TGA, dynamic mechanical analysis, and tensile test. These directly prepared cPAs exhibited Tg of 1–39 °C, tensile strength of up to 45 MPa, and strain at break from 18% to 40%. The cPAs with high tensile strength and good toughness were successfully synthesized through the direct bulk Michael addition from HDA and MA followed with polycondensation.
Truxene-based Conjugated Microporous Polymers via Different Synthetic Methods
Meng-Yang Wang, Qiu-Jing Zhang, Qiao-Qiao Shen, Qing-Yin Li, Shi-Jie Ren
2020, 38(2): 151 -157.   doi: 10.1007/s10118-019-2321-1
[Abstract](466) [FullText HTML](149) [PDF 396KB](18)
Four truxene-based conjugated microporous polymers (Tr-CMPs) were prepared via different synthetic methods and their structure-property relationships were studied. The polymer networks have high Brunauer-Emmett-Teller (BET) specific surface areas ranging from 554 m2·g–1 to 1024 m2·g–1. Pore sizes of the CMPs with different linkers are mainly located between 0.60 and 1.96 nm. Among all the Tr-CMPs, Tr-CMP4 has the highest BET surface area of 1024 m2·g–1 and exhibits the highest H2 uptake of 0.88 wt%. Tr-CMP2 prepared by Suzuki-Miyaura coupling reaction has the highest photoluminescence quantum yields (PLQYs) of 13.06% and CO2 uptake of 6.25 wt%.
Crystallization Behavior and Dynamic Mechanical Properties of Poly(ε-caprolactone)/Octaisobutyl-Polyhedral Oligomeric Silsesquioxanes Composites Prepared via Different Methods
Si-Qi Teng, Zhi-Guo Jiang, Zhao-Bin Qiu
2020, 38(2): 158 -163.   doi: 10.1007/s10118-020-2338-5
[Abstract](305) [FullText HTML](22) [PDF 542KB](16)
Two octaisobutyl-polyhedral oligomeric silsesquioxanes (oib-POSS) reinforced biodegradable poly(ε-caprolactone) (PCL) composites were prepared via two different methods, i.e., melt compounding and solution casting, which were named as mPCL/oib-POSS and sPCL/oib-POSS, respectively, in this work. Oib-POSS dispersed finely in both composites; moreover, oib-POSS aggregates were larger in mPCL/oib-POSS than in sPCL/oib-POSS. Despite the different preparation methods, oib-POSS obviously promoted the crystallization of PCL, especially in sPCL/oib-POSS, but did not modify the crystal structure of PCL. The storage moduli of PCL were improved significantly in both composites. PCL/oib-POSS composites with enhanced crystallization behavior and improved dynamic mechanical properties were successfully prepared through both methods; moreover, the solution casting method was more effective than the melt compounding method.
Differential Polymorphic Transformation Behavior of Polybutene-1 with Multiple Isotactic Sequences
Ya-Ping Ma, Wei-Ping Zheng, Chen-Guang Liu, Hua-Feng Shao, Hua-Rong Nie, Ai-Hua He
2020, 38(2): 164 -173.   doi: 10.1007/s10118-020-2337-6
[Abstract](381) [FullText HTML](140) [PDF 1188KB](18)
For the solid-solid transformation from form II to form I of isotactic polybutene-1 (iPB), the temperature dependence of form I nucleation and growth was deemed to control the transformation process. However, the relationship between form I formation and form II disappearance in the transformation process is not clear. In this work, the spontaneous crystal transformation from form II to I of iPB with 81 mol% mmmm sequence concentration is studied firstly by tracking the two processes, the decay of form II and the yielding of form I in a wide range of temperature spanning from 0 °C to 50 °C and in a long transformation time ranging from 5 min to 65 days with in situ FTIR and WAXD. Unlike the literature reports, the decay rate of form II is firstly found to be lower than the yielding rate of form I at all studied temperatures, especially at low transition temperature. This is attributed to the amorphous chains which locate near crystal lamella participating into the nucleation of form II. The regular chain folding and growth of iPB form I from amorphous chains containing short isotactic sequences also lead to an increase in crystallinity of form I compared with that of initial form II crystallized at 60 °C. An increase in the annealing temperature results in decrease in crystallinity and increase in lamellae thickness of iPB form I.
Competition between Liquid-liquid De-mixing, Crystallization, and Glass Transition in Solutions of PLA of Different Stereochemistry and DEET
Chanita Sungkapreecha, Walter W. Focke, René Androsch
2020, 38(2): 174 -178.   doi: 10.1007/s10118-019-2314-0
[Abstract](385) [FullText HTML](64) [PDF 324KB](6)
Liquid-liquid (L-L) de-mixing and vitrification of solutions of either crystallizable poly(L-lactic acid) (PLLA) or non-crystallizable poly(D/L-lactic acid) (PDLLA) with 50 m% N,N-diethyl-3-methylbenzamide (DEET) were analyzed by calorimetry and cloud-point measurements, which allows drawing conclusions about the effect of polymer stereochemistry on the phase behavior. Regardless of the PLA stereochemistry, vitrification of the solutions on fast cooling, hindering crystallization of PLLA, occurred below −20 °C and suppressed prior L-L de-mixing. The experimental results prove that crystallization in samples containing crystallizable PLLA, observed at around 55 °C on slow cooling, is not preceded by L-L de-mixing.
Numerical Simulation of the Distribution Function and Free Energy of a Single Wormlike Polymer Confined between Hard Walls
Yang Gu, Hui Zhang, Dong-Liang Zhang
2020, 38(2): 179 -186.   doi: 10.1007/s10118-019-2322-0
[Abstract](327) [FullText HTML](115) [PDF 847KB](10)
We focus on the distribution and free energy of a wormlike polymer confined between two parallel hard walls. The variation in the distribution and free energy of the wormlike chain as the spacing between the walls decreases (or as the total contour length of the wormlike chain increases or as the persistence length of the chain increases) is simulated. The main reason for these changes is a degradation of the long wormlike chain into a Gaussian long chain under weak confinement.
Selective Carbon Dioxide Capture in Antifouling Indole-based Microporous Organic Polymers
Meng-Qi Du, Yu-Zheng Peng, Yuan-Chi Ma, Li Yang, Yuan-Lin Zhou, Fan-Kun Zeng, Xiang-Ke Wang, Man-Ling Song, Guan-Jun Chang
2020, 38(2): 187 -194.   doi: 10.1007/s10118-019-2326-9
[Abstract](438) [FullText HTML](159) [PDF 469KB](9)
Intermolecular synergistic adsorption of indole and carbonyl groups induced by intermolecular hydrogen bonding makes microporous organic polymer (PTICBL) exhibit high CO2 uptake capacity (5.3 mmol·g−1 at 273 K) and selectivities (CO2/CH4 = 53, CO2/N2 = 107 at 273 K). In addition, we find that indole units in the PTICBL networks inhibit the attachment of bacteria (E. coil and S. aureus) on the surface of PTICBL and extend its service life in CO2 capture.
Poly(methyl methacrylate)-induced Microstructure and Hydrolysis Behavior Changes of Poly(L-lactic acid)/Carbon Nanotubes Composites
Xu Yu, Xin-Zheng Jin, Ting Huang, Nan Zhang, Xiao-Yu Li, Yong Wang
2020, 38(2): 195 -204.   doi: 10.1007/s10118-019-2323-z
[Abstract](369) [FullText HTML](76) [PDF 502KB](11)
Poly(L-lactic acid) (PLLA)-based composites exhibit wide applications in many fields. However, most of hydrophilic fillers usually accelerate the hydrolytic degradation of PLLA, which is unfavorable for the prolonging of the service life of the articles. In this work, a small quantity of poly(methyl methacrylate) (PMMA) (2 wt%−10 wt%) was incorporated into the PLLA/carbon nanotubes (CNTs) composites. The effects of PMMA content on the dispersion of CNTs as well as the microstructure and hydrolytic degradation behaviors of the composites were systematically investigated. The results showed that PMMA promoted the dispersion of CNTs in the composites. Amorphous PLLA was obtained in all the composites. Largely enhanced hydrolytic degradation resistance was achieved by incorporating PMMA, especially at relatively high PMMA content. Incorporating 10 wt% PMMA led to a dramatic decrease in the hydrolytic degradation rate from 0.19 %/h of the PLLA/CNT composite sample to 0.059 %/h of the PLLA/PMMA-10/CNT composite sample. The microstructure evolution of the composites was also detected, and the results showed that no crystallization occurred in the PLLA matrix. Further results based on the interfacial tension calculation showed that the enhanced hydrolytic degradation resistance of the PLLA matrix was mainly attributed to the relatively strong interfacial affinity between PMMA and CNTs, which prevented the occurrence of hydrolytic degradation at the interface between PLLA and CNTs. This work provides an alternative method for tailoring the hydrolytic degradation ability of the PLLA-based composites.