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Rational Design of Biomolecules/Polymer Hybrids by Reversible Deactivation Radical Polymerization (RDRP) for Biomedical Applications
Jie Zhou, Xiao-Yuan Zhang, Zhi-Qiang Su
Corrected proof , doi: 10.1007/s10118-021-2543-x
[Abstract](21) [FullText HTML](10) [PDF 24675KB](0)
Hybrids, produced by hybridization of proteins, peptides, DNA, and other new biomolecules with polymers, often have unique functional properties. These properties, such as biocompatibility, stability and specificity, lead to various smart biomaterials. This review mainly introduces biomolecule-polymer hybrid materials by reversible deactivation radical polymerization (RDRP), emphasizing reverse addition-fragmentation chain transfer (RAFT) polymerization, and nitroxide mediated polymerization (NMP). It includes the methods of RDRP to improve the biocompatibility of biomedical materials and organisms by surface modification. The key to the current synthesis of biomolecule-polymer hybrids is to control polymerization. Besides, this review describes several different kinds of biomolecule-polymer hybrid materials and their applications in the biomedical field. These progresses provide ideas for the investigation of biodegradable and highly bioactive biomedical soft tissue materials. The research hotspots of nanotechnology in biomedical fields are controlled drug release materials and gene therapy carrier materials. Research showed that RDRP method could improve the therapeutic effect and reduce the dosage and side effects of the drug. Specifically, by means of RDRP, the original materials can be modified to develop intelligent polymer materials as membrane materials with selective permeability and surface modification.
Scattering Function and Spinodal Transition of Linear and Nonlinear Block Copolymers Based on a Unified Molecular Model
Weichao Shi
Corrected proof , doi: 10.1007/s10118-021-2544-9
[Abstract](21) [FullText HTML](7) [PDF 0KB](0)
This work uses a block copolymer architecture [(A’B)nA2]m to unify the scattering function and spinodal transition of typical AB-type block copolymers. The key roles of block number, junction points and asymmetry ratios of block length are (1) to determine the form factor of each block copolymer at the molecular scale; (2) to affect the entropy loss across the spinodal transition and may result in deflection of spinodal curves. The common features are validated in typical linear and nonlinear block copolymers, including AB diblock, asymmetric A’BA triblock, miktoarm stars of ABn, AnBn, (AB)n, (A’B)nA, A’BAm, and multi-graft combs of (BnA2)m and [(A’B)nA2]m. The explicit scattering functions and form factors of various block copolymers can be directly applied in radiation experiments (i.e. neutron or X-ray scattering) to unravel the effect of molecular architecture in solution and microphase separation in disordered melt. The molecular model used in this study is also helpful to guide the chemical synthesis to explore more potentially interesting block copolymers.
A Single-wavelength NIR-triggered Polymer for in Situ Generation of Peroxynitrite (ONOO) to Enhance Phototherapeutic Efficacy
Xiang Zhang, Da-Wei Jiang, Guo-Liang Yang, Yu-Cheng Zhu, Jia Tian, Hong-Liang Cao, Yun Gao, Wei-An Zhang
Corrected proof , doi: 10.1007/s10118-021-2540-0
[Abstract](114) [FullText HTML](60) [PDF 724KB](0)
Phototherapies including photodynamic therapy (PDT) and photothermal therapy (PTT) are the most promising and non-invasive cancer treatments. However, the efficacy of mono-therapy of PDT or PTT is often limited by the phototherapeutic defects such as low light penetration depth of photosensitizers and insufficiency of photothermal agents. Peroxynitrite (ONOO) has been proved to be an efficient oxidizing and nitrating agent that involves in various physiological and pathological processes. Therefore, ONOO produced in tumor site could be an effective treatment in cancer therapy. Herein, a novel cyanine dye-based (Cy7) polymer nanoplatform is developed for enhanced phototherapy by in situ producing ONOO. The Cy7 units in the nanoparticles can not only be served as the photosensitizer to produce reactive oxygen species (ROS) including singlet oxygen and superoxide anion for PDT, but also be used as a heat source for PTT and the release of NO gas from N-nitrosated napthalimide (NORM) at the same time. Since NO can react quickly with superoxide anion to generate ONOO, the enhanced phototherapy could be achieved by in situ ONOO produced by PCy7-NO upon exposure to the near infrared (NIR) light. Therefore, the NIR-triggered Cy7-based nanoplatform for ONOO-enhanced phototherapy may provide a new perspective in cancer therapy.
Enzyme-assisted Photoinitiated Polymerization-induced Self-assembly in Continuous Flow Reactors with Oxygen Tolerance
Wei-Bin Cai, Dong-Dong Liu, Ying Chen, Li Zhang, Jian-Bo Tan
Corrected proof , doi: 10.1007/s10118-021-2533-z
[Abstract](242) [FullText HTML](62) [PDF 915KB](4)
Polymerization-induced self-assembly (PISA) is an emerging method for the preparation of block copolymer nano-objects at high concentrations. However, most PISA formulations have oxygen inhibition problems and inert atmospheres (e.g. argon, nitrogen) are usually required. Moreover, the large-scale preparation of block copolymer nano-objects at room temperature is challenging. Herein, we report an enzyme-assisted photoinitiated polymerization-induced self-assembly (photo-PISA) in continuous flow reactors with oxygen tolerance. The addition of glucose oxidase (GOx) and glucose into the reaction mixture can consume oxygen efficiently and constantly, allow the flow photo-PISA to be performed under open-air conditions. Polymerization kinetics indicated that only a small amount of GOx (0.5 μmol/L) was needed to achieve the oxygen tolerance. Block copolymer nano-objects with different morphologies can be prepared by varying reaction conditions including the degree of polymerization (DP) of core-forming block, monomer concentration, reaction temperature, and solvent composition. We expect this study will provide a facile platform for the large-scale production of block copolymer nano-objects with different morphologies at room temperature.
Synergic Enhancement of High-density Polyethylene through Ultrahigh Molecular Weight Polyethylene and Multi-flow Vibration Injection Molding: A Facile Fabrication with Potential Industrial Prospects
Rui Hong, Yi-Xin Jiang, Jie Leng, Ming-Jin Liu, Kai-Zhi Shen, Qiang Fu, Jie Zhang
Corrected proof , doi: 10.1007/s10118-021-2545-8
[Abstract](102) [FullText HTML](58) [PDF 0KB](0)
General-purpose plastics with high strength and toughness have been in great demand for structural engineering applications. To achieve the reinforcement and broaden the application scope of high-density polyethylene (HDPE), multi-flow vibration injection molding (MFVIM) and ultrahigh molecular weight polyethylene (UHMWPE) are synergistically employed in this work. Herein, the MFVIM has better shear layer control ability and higher fabrication advantage for complex parts than other analogous novel injection molding technologies reported. The reinforcing effect of various filling times and UHMWPE contents as well as the corresponding microstructure evolution are investigated. When 5 wt% UHMWPE is added, MFVIM process with six flow times thickens the shear layer to the whole thickness. The tensile strength and modulus increase to 2.14 and 1.39 times, respectively, compared to neat HDPE on the premise of remaining 70% impact strength. Structural characterizations indicate that the enhancement is attributed to the improvement of shish-kebab content and lamellae compactness, as well as related to the corresponding size distributions of undissolved UHMWPE particles. This novel injection molding technology with great industrial prospects provides a facile and effective strategy to broaden the engineering applications of HDPE materials. Besides, excessive UHMWPE may impair the synergistic enhancement effect, which is also reasonably explained.
Nanocrystallization-locked Network of Poly(styrene-b-isobutylene-b-styrene)-g-Polytetrahydrofuran Block Graft Copolymer
Hang-Tian Zhang, Zhi-Tao Wei, Fang Zhang, Tian Yang, Yi-Xian Wu
Corrected proof , doi: 10.1007/s10118-021-2536-9
[Abstract](277) [FullText HTML](125) [PDF 1629KB](0)
Poly(styrene-b-isobutylene-b-styrene) triblock copolymer (SIBS), a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments, could be synthesized via living cationic copolymerization. A novel poly[(styrene-co-methylstyrene)-b-isobutylene-b-(styrene-co-methylstyrene)]-g-polytetrahydrofuran (M-SIBS-g-PTHF) block graft copolymer was prepared to increase the polarity and service temperature of SIBS by grafting polar PTHF segments onto SIBS. A series of the above block graft copolymers with average grafting numbers from 2 to 6 and molecular weights of PTHF branches ranging from 200 g·mol−1 to 4200 g·mol−1 were successfully synthesized via living cationic ring-opening polymerization of tetrahydrofuran (THF) coinitiated by AgClO4. The introduction of PTHF branches led to an obvious microphase separation due to thermodynamic incompatibility among the three kinds of segments of polyisobutylene (PIB), polystyrene (PS) and PTHF. Moreover, the microphase separation promotes the rearrangement of PTHF branches to form the nanocrystallization-locked physically cross-linked network after storage at room temperature for 2 months, leading to insolubility of the copolymers even in good solvents. The melting temperature and enthalpy of PTHF nanocrystallization locked in hard domains of M-SIBS-g5-PTHF-1.1k block graft copolymer increased remarkably up to 153 °C and 117.0 J·g−1 by 23 °C and 11.6 J·g−1 respectively after storage for long time. Storage modulus (G') is higher than loss modulus (G'') of M-SIBS-g-PTHF block graft copolymer at temperatures ranging from 100 °C to 180 °C, which is much higher than those of the SIBS triblock copolymer. To the best of our knowledge, this is the first example of high performance M-SIBS-g-PTHF block graft copolymers containing segments of PIB, PS and PTHF with nanocrystallization-locked architecture.
Comparison of the Structural Evolution of β Polypropylene during the Sequential and Simultaneous Biaxial Stretching Process
Dao-Xin Zhang, Lei Ding, Feng Yang, Fang Lan, Ya Cao, Ming Xiang
Corrected proof , doi: 10.1007/s10118-021-2534-y
[Abstract](290) [FullText HTML](112) [PDF 6079KB](0)
In this work, the lamellar structural evolution and microvoids variations of β polypropylene (β-PP) during the processing of two different stretching methods, sequential biaxial stretching and simultaneous biaxial stretching, were investigated in detail. It was found that different stretching methods led to significantly different lamellae deformation modes, and the microporous membranes obtained from the simultaneous biaxial stretching exhibited better mechanical properties. For the sequential biaxial stretching, abundant coarse fibers originated from the tight accumulation of the lamellae parallel to the longitudinal stretching direction, whereas the lamellae perpendicular to the stretching direction were easily deformed and separated. Those coarse fibers were difficult to be separated to form micropores during the subsequent transverse stretching process, resulting in a poor micropores distribution. However, for the simultaneous biaxial stretching, the β crystal had the same deformation mode, that is, the lamellae distributed in different directions were all destroyed, forming abundant microvoids and little coarse fibers.
Challenges and Recent Developments of Photoflow-Reversible Deactivation Radical Polymerization (RDRP)
Zhuo-Ran Zhong, Yi-Nan Chen, Yang Zhou, Mao Chen
Corrected proof , doi: 10.1007/s10118-021-2529-8
[Abstract](496) [FullText HTML](144) [PDF 1199KB](0)
Photo-controlled reversible-deactivation radical polymerization (photo-RDRP) has been investigated as a “green” and spatiotemporally controlling pathway for polymer synthesis. While the combination of photo-RDRP and flow chemistry has offered opportunities to increase light intensity and enable uniform light irradiation, problems associated with flow approaches still remain for photoflow-RDRP, which has hindered merging flow polymerization with other cutting-edge techniques. Herein, we summarize challenges and recent achievements in photoflow-RDRP including the development of (a) droplet/slug-flow to regulate residence time distribution, (b) mixing techniques to tailor polymer, (c) polymerization induced self-assembly, and (d) computer-aided synthesis. We hope this work will provide informative knowledge to people in related fields and stimulate novel ideas to promote polymer synthesis in both academia and industry.
Synthesis of Well-defined Poly(tetrahydrofuran)-b-Poly(α-amino acid)s via Cationic Ring-opening Polymerization (ROP) of Tetrahydrofuran and Nucleophilic ROP of N-thiocarboxyanhydrides
Peng Zhou, Xuan-Geng Dai, Jie Kong, Jun Ling
Corrected proof , doi: 10.1007/s10118-021-2539-6
[Abstract](245) [FullText HTML](121) [PDF 957KB](0)
The synthesis of block copolymers of poly(tetrahydrofuran)-b-poly(α-amino acid) (PTHF-b-PAA) is challenging since it is difficult to combine the two blocks produced via different/conflicting ring-opening polymerization (ROP) mechanisms. In this contribution, the cationic ROP of THF is catalyzed by rare-earth triflate [RE(OTf)3] and terminated by 2-(t-butyloxycarbonyl-amino) ethanol (BAE). After the deprotection of t-butyloxycarbonyl (Boc) group, the chain end of PTHF is quantitatively changed to amino group which thereafter initiates the nucleophilic ROP of α-amino acid N-thiocarboxyanhydrides (NTAs). Both polymerizations are well controlled, generating PTHF and PAA segments with designable molecular weights (MWs). PTHF-b-polylysine (PTHF-b-PLys) and PTHF-b-polysarcosine (PTHF-b-PSar) are obtained with MWs between 8.6 and 28.7 kg/mol. The above amphiphilic diblock copolymers form micelles in water. PTHF40-b-PSar32 acts as a surfactant to stabilize oil-in-water emulsions. Both segments of PTHF-b-PAA are biocompatible and promising in the biomedical application.
A Triple Crosslinking Design toward Epoxy Vitrimers and Carbon Fiber Composites of High Performance and Multi-shape Memory
Hao Wang, Han-Chao Liu, Yao Zhang, Hu Xu, Bi-Qiang Jin, Zhen-Xing Cao, Hai-Tao Wu, Guang-Su Huang, Jin-Rong Wu
Corrected proof , doi: 10.1007/s10118-021-2538-7
[Abstract](248) [FullText HTML](92) [PDF 710KB](2)
It remains a challenge to use a simple approach to fabricate a multi-shape memory material with high mechanical performances. Here, we report a triple crosslinking design to construct a multi-shape memory epoxy vitrimer (MSMEV), which exhibits high mechanical properties, multi-shape memory property and malleability. The triple crosslinking network is formed by reacting diglycidyl ether of bisphenol F (DGEBF) with 4-aminophenyl disulfide, γ-aminopropyltriethoxysilane (APTS) and poly(propylene glycol) bis(2-aminopropyl ether) (D2000). The triple crosslinking manifests triple functions: the disulfide bonds and the silyl ether linkages enable malleability of the epoxy network; the silyl ether linkages impart the network with high heterogeneity and broaden the glass transition region, leading to multi-shape memory property; a small amount of D2000 increases the modulus difference between the glassy and rubbery states, thereby improving the shape fixity ratio. Meanwhile, the high crosslinking density and rigid structure provide the MSMEV with high tensile strength and Young’s modulus. Moreover, integrating carbon fibers and MSMEV results in shape memory composites. The superior mechanical properties of the composites and the recyclability of carbon fiber derived from the dissolvability of MSMEV make the composites hold great promise as structural materials in varied applications.
Benzothiadiazole-based Conjugated Polymers for Organic Solar Cells
Chao Wang, Feng Liu, Qiao-Mei Chen, Cheng-Yi Xiao, Yong-Gang Wu, Wei-Wei Li
Corrected proof , doi: 10.1007/s10118-021-2537-8
[Abstract](270) [FullText HTML](97) [PDF 557KB](2)
Benzothiadiazole (BT) is an electron-deficient unit with fused aromatic core, which can be used to construct conjugated polymers for application in organic solar cells (OSCs). In the past twenty years, huge numbers of conjugated polymers based on BT unit have been developed, focusing on the backbone engineering (such as by using different copolymerized building blocks), side chain engineering (such as by using linear or branch side units), using heteroatoms (such as F, O and S atoms, and CN group), etc. These modifications enable BT-polymers to exhibit distinct absorption spectra (with onset varied from 600 nm to 1000 nm), different frontier energy levels and crystallinities. As a consequence, BT-polymers have gained much attention in recent years, and can be simultaneously used as electron donor and electron acceptor in OSCs, providing the power conversion efficiencies (PCEs) over 18% and 14% in non-fullerene and all-polymer OSCs. In this article, we provide an overview of BT-polymers for OSCs, from donor to acceptor, via selecting some typical BT-polymers in different periods. We hope that the summary in this article can invoke the interest to study the BT-polymers toward high performance OSCs, especially with thick active layers that can be potentially used in large-area devices.
Isoselective Ring-opening Polymerization of Racemic Lactide Catalyzed by N-heterocyclic Olefin/(Thio)urea Organocatalysts
Zhen-Yu Wang, Guang-Qiang Xu, Li Zhou, Cheng-Dong Lv, Ru-Lin Yang, Bing-Zhe Dong, Qing-Gang Wang
Corrected proof , doi: 10.1007/s10118-021-2535-x
[Abstract](177) [FullText HTML](91) [PDF 462KB](0)
The isoselective ring-opening polymerization of racemic lactide was achieved by combining N-heterocyclic olefin (NHO) with mono(thio)ureas or bis(thio)ureas as catalytic systems. The polymerization process shows high stereoselectivity, controllability and reactivity, delivering multi-block isotactic polylactides with high chain-end fidelity and narrow molecular weight distributions. The enhancement of catalytic performance was observed in the following order: bisthiourea (DTU) < monothiourea (TU) < bisurea (DU) < urea (U). The highest Pm (probability of forming a meso dyad) = 0.91 was observed at −70 °C when using NHO/U1 catalytic system and the high stereoselectivity was attributed to chain-end control mechanism.
Barium Titanate-reinforced Acrylonitrile-Butadiene Rubber: Synergy Effect of Carbon-based Secondary Filler
Wannarat Chueangchayaphan, Piyawadee Luangchuang, Narong Chueangchayaphan, Muhammad Azwadi Sulaiman, Yeampon Nakaramontri
Corrected proof , doi: 10.1007/s10118-021-2528-9
[Abstract](193) [FullText HTML](89) [PDF 0KB](2)
Acrylonitrile rubber (NBR) composites filled with barium titanate (BT) were prepared using an internal mixer and a two-roll mill. Also, a secondary filler, namely carbon nanotubes (CNT), was added in order to find a potential synergistic blend ratio of BT and CNT. The cure characteristics, tensile and dielectric properties (dielectric constant and dielectric loss) of the composites were determined. It was found that NBR/BT composites with CNT secondary filler, at a proper BT:CNT ratio, exhibited shorter scorch time (ts1) and cure time (tc90) together with superior tensile properties and reinforcement efficiency, relative to the one with only the primary filler. In addition, the NBR/BT-CNT composite with 80 phr BT and 1−2 phr CNT had dielectric constant of 100−500, dielectric loss of 12−100 and electrical conductivity below 10−4 S/m together with high thermal stability. Thus, with a proper BT:CNT mix and filler loading, we can produce mechanically superior rubber composites that are easy to process and low-cost, for flexible dielectric materials application.
Reversible Mechanochemistry Enabled Autonomous Sustaining of Robustness of Polymers—An Example of Next Generation Self-healing Strategy
Ming-Xuan Li, Min-Zhi Rong, Ming-Qiu Zhang
Corrected proof , doi: 10.1007/s10118-021-2532-0
[Abstract](330) [FullText HTML](146) [PDF 684KB](3)
Even under low external force, a few macromolecules of a polymer have to be much more highly stressed and fractured first due to the inherent heterogeneous microstructure. When the materials keep on working under loading, as is often the case, the minor damages would add up, endangering the safety of use. Here we show an innovative solution based on mechanochemically initiated reversible cascading variation of metal-ligand complexations. Upon loading, crosslinking density of the proof-of-concept metallopolymer networks autonomously increases, and recovers after unloading. Meanwhile, the stress-induced tiny fracture precursors are blocked to grow and then restored. The entire processes reversibly proceed free of manual intervention and catalyst. The proposed molecular-level internal equilibrium prevention mechanisms fundamentally enhance durability of polymers in service.
Melting and Annealing Peak Temperatures of Poly(butylene succinate) on the Same Hoffman-Weeks Plot Parallel to Tm=Tc Line
Zhi-Ning Xie, Hai-Mu Ye, Tong Chen, Tian-Ze Zheng, Jun Xu, Bao-Hua Guo
Corrected proof , doi: 10.1007/s10118-021-2530-2
[Abstract](269) [FullText HTML](139) [PDF 632KB](0)
The crystallization and melting behavior of polymers is of theoretical importance. In this work, poly(butylene succinate) (PBS) was selected as an example to study such behavior at low supercooling via introduction of the extended-chain crystal (ECC) of the same polymer as nucleating agent. The crystallization of PBS with its ECC as nucleating agent in a wide temperature range (90–127 °C) and the following melting behavior were studied. It is revealed that the melting point (Tm, for Tc≥113 °C) and the annealing peak temperature (Ta, for Tc=90–100 °C) show similar asymptotic behavior. Both Tm and Ta approach to a value of ca. 3.3 °C higher than the corresponding Tc when the crystallization time tc approaches the starting point. That is to say, the Hoffman-Weeks plot is parallel to Tm=Tc line. The crystallization line became parallel to the melting line when PBS was crystallized at Tc higher than 102 °C. Based on these results, we propose that the parallel relationship and the intrinsic similarity between the Ta and the Tm observed at the two ends of the Tc range could be attributed to the metastable crystals formed at the beginning of crystallization.
Tailoring Morphology of PVDF-HFP Membrane via One-step Reactive Vapor Induced Phase Separation for Efficient Oil-Water Separation
Peng Huo, Cheng-Tang Zhong, Xiao-Peng Xiong
Corrected proof , doi: 10.1007/s10118-021-2527-x
[Abstract](314) [FullText HTML](137) [PDF 1104KB](1)
Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) receives increasing attention in membrane separation field based on its advantages such as high mechanical strength, thermal and chemical stability. However, controlling the microporous structure is still challenging. In this work, we attempted to tailor the morphology of PVDF-HFP membrane via a one-step reactive vapor induced phase separation method. Namely, PVDF-HFP was dissolved in a volatile solvent and then was cast in an ammonia water vapor atmosphere. After complete evaporation of solvent, membranes with adjustable porous structure were prepared, and the microstructures of the membranes were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction characterizations. Based on the results, a mechanism of dehydrofluorination induced cross-linking of PVDF-HFP has been suggested to understand the morphology tailoring. To our knowledge, this is the first report of one-step reactive vapor induced phase separation strategy to tailor morphology of PVDF-HFP membrane. In addition, the membranes prepared in the ammonia water vapor exhibited enhanced mechanical strength and achieved satisfactory separation efficiency for water-in-oil emulsions, suggesting promising potential.
Foam/Film Alternating Multilayer Structure with High Toughness and Low Thermal Conductivity Prepared via Microlayer Coextrusion
Qi Luo, Hong-Ting Pu, Zhi-Hua Zhang, Xiong Zhang, Cheng-Long Yu
Corrected proof , doi: 10.1007/s10118-021-2524-0
[Abstract](253) [FullText HTML](118) [PDF 1092KB](0)
Multilayer membranes prepared via microlayer coextrusion have attracted wide attention due to their unique properties and broad applications. In present study, the foam/film alternating multilayer sheets based on ethylene-vinyl acetate copolymer (EVA) and high-density polyethylene are successfully prepared via microlayer coextrusion. The cells in the sheets are single-cell-array along the foamed EVA layers with uniform cell size. In addition, the effects of layer number and foam relative thickness on morphology, mechanical properties, damping and heat insulation properties are investigated. The cell size decreases significantly with increasing layer number due to the enhanced confine effects. The tensile strength, elongation at break, and heat insulation also increase significantly. However, the mechanical damping properties change little in the observed frequency. Meanwhile, with higher relative thickness of EVA foam, the sheets have lower tensile strength and lower thermal conductivity, while the damping properties are enhanced in a specific frequency scope. The elongation at break of the optimized sample comes to 800% and the thermal conductivity decreases to 61 mW·m−1·K−1, which shows high toughness and low thermal conductivity, indicating a possible method for preparing materials with high toughness and heat-insulating properties.
Tunable Lower Critical Solution Temperature of Poly(butyl acrylate) in Ionic Liquid Blends
Lie Chen, Jin Huang, Cong Zhao, Jia-Jia Zhou, Ming-Jie Liu
Corrected proof , doi: 10.1007/s10118-021-2522-2
[Abstract](356) [FullText HTML](124) [PDF 337KB](0)
We describe the lower critical solution temperature (LCST)-type phase behavior of poly(butyl acrylate) (PBA) dissolved in hydrophobic 1-alkyl-3-methylimidazolium bis{(trifluoromethyl) sulfonyl}amide ionic liquids (ILs). The temperature-composition phase diagrams of these PBA/ILs systems are strongly asymmetric with the critical composition shifted to low concentrations of PBA. As the molecular weight increases from 5.0×103 to 2.0×104, the critical temperature decreases by about 67 °C, and the critical composition shifts to a lower concentration. Furthermore, the LCST of PBA/ILs system increases as increasing the alkyl side chain length in the imidazolium cation. Using IL blends as solvents, the LCST of PBA can be tuned almost linearly over a wide range by varying the mixing ratio of two ionic liquids without modifying the chemical structure of the polymers.
A Conjugated Copolymer Bearing Imidazolium-based Ionic Liquid: Electrochemical Synthesis and Electrochromic Properties
Xiao-Jing Lv, Li-Bin Xu, Liang Qian, Yuan-Yuan Yang, Zhi-Yi Xu, Jin Li, Cheng Zhang
Corrected proof , doi: 10.1007/s10118-021-2525-z
[Abstract](401) [FullText HTML](131) [PDF 1074KB](0)
An imidazolium-based ionic liquid (IL) modified triphenylamine derivative, namely 1-(4-((4-(diphenylamino)benzoyl) oxy)butyl)-3-methyl imidazole tetrafluoroborate (TPAC6IL-BF4), was designed and synthesized, and further applied with 3,4-ethylene dioxythiophene (EDOT) to prepare conjugated copolymer P(EDOT:TPAC6IL-BF4) via electrochemical polymerization. The cyclic voltammetry curves show that the copolymer P(EDOT:TPAC6IL-BF4) possesses two pairs of redox peaks, which should be ascribed to the redox behaviors of EDOT and triphenylamine. The ultraviolet-visible (UV-Vis) absorption spectrum of P(EDOT:TPAC6IL-BF4) exhibits one maximum absorption peak at 580 nm and a small shoulder characteristic peak at 385 nm under neutral state which are assigned to π-π* conjugated structure of EDOT and triphenylamine. After being applied at the positive voltage, the copolymer color changes from dark blue to light blue, which is close to the color of poly(3,4-ethylenedioxythiophene) (PEDOT). Surprisingly, the copolymer P(EDOT:TPAC6IL-BF4) shows shorter switching time of 0.37 s, 0.30 s at 580 nm and 0.38 s, 0.45 s at 1100 nm compared with PEDOT. It is more intriguing that the copolymer P(EDOT:TPAC6IL-BF4) exhibits electrochromism even in free supporting electrolyte. The results confirm that the existence of imidazolium-based ionic liquid has an improvement on the ion diffusion properties and the switching time of conjugated polymer, which may provide a potential direction for the preparation of high-performance electrochromic materials.
Conformational and Dynamical Evolution of Block Copolymers in Shear Flow
Xiang-Xin Kong, Wen-Duo Chen, Feng-Chao Cui, Yun-Qi Li
Corrected proof , doi: 10.1007/s10118-021-2523-1
[Abstract](281) [FullText HTML](122) [PDF 2810KB](0)
Conformation and dynamical evolution of block copolymers in shear flow is an important topic in polymer physics that underscores the forming process of various materials. We explored deformation and dynamics of copolymers composed of rigid or flexible blocks in simple shear flow by employing multiparticle collision dynamics integrated with molecular dynamics simulations. We found that compared with the proportion between rigid and flexible blocks, the type of the central blocks plays more important role in the conformational and dynamical evolution of copolymers. That is, if the central block is a coil, the copolymer chain takes end-over-end tumbling motion, while if the central block is a rod, the copolymer chain undergoes U-shape or S-shape deformation at mid shear rate. As the shear strength increases, all copolymers behave similar to flexible polymers at high shear rate. This can be attributed to the fact that shear flow is strong enough to overcome the buckling force of the rigid blocks. These results provide a deeper understanding of the roles played by rod and coil blocks in copolymers for phase interface during forming processing.
Visualization of Two-dimensional Single Chains of Hybrid Polyelectrolytes on Solid Surface
Lan-Lan Zhang, Wen-Ke Miao, Li-Jun Ren, Yu-Kun Yan, Wei Wang
Corrected proof , doi: 10.1007/s10118-021-2520-4
[Abstract](252) [FullText HTML](129) [PDF 1005KB](0)
The polyacidic character of polyoxometalate (POM) clusters endows high ionic conductivity, making these clusters good candidates for solar and fuel cells. Covalent bonding of clusters to polymer chains creates poly(POM)s that are polyelectrolytes with both cluster functions and polymer performance. Thus, solution-processable poly(POM)s are expected to be used as key materials in advanced devices. Further understanding of poly(POM)s will optimize the preparation process and improve device performance. Herein, we report a study of the first linear poly(POM)s by directly visualizing the chains using scanning transmission electron microscopy. Compared with traditional polymers, individual clusters of poly(POM)s can be directly visualized because of the resistance to electron-beam damage and the high contrast of the tungsten POM pendants. Thus, cluster aggregates with diverse shapes were observed. Counting the number of clusters in the aggregates allowed the degree of polymerization and molecular weight distribution to be determined, and studying the aggregate shapes revealed the presence of a curved semi-rigid chain in solution. Further study of shape diversity revealed that strong interactions between clusters determine the diverse chain shapes formed during solution processing. Fundamental insight is critical to understanding the formation of poly(POM) films from solutions as key functional materials, especially for fuel and solar cells.
Tough Double Metal-ion Cross-linked Elastomers with Temperature-adaptable Self-healing and Luminescence Properties
Qi-Yan Yin, Cheng-Hao Dai, Huan Chen, Kai Gou, Hong-Zhou Guan, Peng-Han Wang, Jing-Tao Jiang, Geng-Sheng Weng
Corrected proof , doi: 10.1007/s10118-021-2517-z
[Abstract](399) [FullText HTML](169) [PDF 820KB](0)
Smart materials with a combination of tough solid-like properties, fast self-healing and optical responsiveness are of interests for the development of new soft machines and wearable electronics. In this work, tough physically cross-linked elastomers that show high mechanical strength, intriguing temperature-adaptable self-healing and fluorochromic response properties are designed using aluminum (Al) and fluorescent europium (Eu) ions as cross-linkers. The ionic Al-COOH binding is incorporated to construct the strong polymer network which mainly contributes to the mechanical robustness of the elastomer consisting of two interpenetrated networks. The Eu-iminodiacetate (IDA) coordination is mainly used to build the weaker but more dynamic network which dominate the elasticity, self-healing and luminescence of the elastomer. Moderate Eu3+ and Al3+ contents give these supramolecular elastomers high toughness. The temperature-sensitive Eu-IDA coordination enables tunable self-healing rate and efficiency along with fast Eu-centered “ON/OFF” switchable red emission. The mechanical, self-healing and luminescence properties of these elastomers can be adjusted by tuning the ratio of the two types of metal ions. This elastomer is potentially applicable for biosensors, wearable optoelectronics and anticounterfeiting materials.
Photoinduced Reversible Solid-to-Liquid Transitions and Directional Photofluidization of Azobenzene-containing Polymers
Shuo-Feng Liang, Chen Nie, Jie Yan, Qi-Jin Zhang, Si Wu
Corrected proof , doi: 10.1007/s10118-021-2519-x
[Abstract](347) [FullText HTML](158) [PDF 798KB](0)
Photoinduced reversible liquefaction and solidification of polymers enable processing and healing of polymers with light. Some azobenzene-containing polymers (azopolymers) exhibit two types of photoinduced liquefaction properties: photoinduced reversible solid-to-liquid transition and directional photofluidization. For the first type, light switches the glass transition temperature (Tg) values of azopolymers and induces reversible solid-to-liquid transitions. For the second type, polarized light guides solid azopolymers to flow along the polarization direction. Here, we compare the two types of photoliquefaction and discuss their mechanisms. Recent progresses and applications based on photoliquefaction of azopolymers are also highlighted.
Stereocomplex Crystallization in Asymmetric Diblock Copolymers Studied by Dynamic Monte Carlo Simulations
Ying Xu, Jun Yang, Zong-Fa Liu, Zhi-Ping Zhou, Zhao-Peng Liang, Tong-Fan Hao, Yi-Jing Nie
Corrected proof , doi: 10.1007/s10118-021-2512-4
[Abstract](385) [FullText HTML](177) [PDF 654KB](0)
Stereocomplex crystallization in asymmetric diblock copolymers was studied using dynamic Monte Carlo simulations, and the key factor dominating the formation of stereocomplex crystallites (SCs) was uncovered. The asymmetric diblock copolymers with higher degree of asymmetry exhibit larger difference between volume fractions of beads of different blocks, and local miscibility between different kinds of beads is lower, leading to lower SC content. To minimize the interference from volume fraction of beads, the SC formation in blends of asymmetric diblock copolymers was also studied. For the cases where the volume fractions of beads of different blocks are the same, similar local miscibility between beads of different blocks and similar SC content was observed. These findings indicate that the volume fraction of beads of different blocks is a key factor controlling the SC formation in the asymmetric diblock copolymers. The SC content can be regulated by adjusting the difference between the contents of beads of different blocks in asymmetric diblock copolymers.
Facile Mechanochemical Preparation of Polyamide-derivatives via Solid-state Benzoxazine-isocyanide Chemistry
Xu Sun, Wei Shi, Xin-Yu Zhou, Sheng Ding
Corrected proof , doi: 10.1007/s10118-021-2510-6
[Abstract](375) [FullText HTML](172) [PDF 1071KB](1)
With the exploration of novel sustainable protocol for functional polyamides’ (PAs) construction as the starting point, herein, the small molecular model compound (M1-ssBIC) was prepared firstly by manual grinding of monofunctional benzoxazine (1a) and isocyanide (1b) via solid-state benzoxazine-isocyanide chemistry (ssBIC) to evaluate the feasibility of ssBIC. Linear PAs (P1-series polymers) were subsequently synthesized from biunctional benzoxazine (2a) and isocyanide (2b), and the influence of the loading of catalyst (octylphosphonic acid) (OPA) on the polymerization was investigated. Afterwards, two kinds of cross-linked PAs were successfully constructed via ssBIC by using trifunctional benzoxazine (3a) and cross-linked polybenzoxazine (4a) as reaction substrates, respectively, thus verifying the adaptability of ssBIC. Structural characterization indicates that amide, phenolic hydroxyl and tertiary amine substructures, with metal-complexing capability, have been successfully integrated into the obtained PAs. A type of representative PA/silver composite (P3-AgNPs) was prepared subsequently via in situ reduction treatment, and its application as recyclable reduction catalyst for organic pollutant p-nitrophenol (4-NP) was preliminarily investigated here to provide the example for possible downstream application of ssBIC. We think that this current work could provide a new pathway for the construction of functional PAs through facile and sustainable ssBIC protocol.
Scalable Reaction-spinning of Rigid-rod Upilex-S® Type Polyimide Fiber with an Ultrahigh Tg
Sen-Sen Zheng, Han Dong, Shi-Hua Wang, Jie Dong, Tao Guo, Xin Zhao, Qing-Hua Zhang
Corrected proof , doi: 10.1007/s10118-021-2508-0
[Abstract](314) [FullText HTML](256) [PDF 0KB](0)
In the family of polyimide (PI) materials, Upilex-S® film has been a shining star through the research PI materials due to its appealing merits. Unfortunately, the wholly rigid-rod backbone and easily formed skin-core micromorphology and microvoids of Upilex-S® type PI lead to the high difficulty in melt- and wet-spinning fabrication. Herein, we propose a facile and scalable method, reaction-spinning, to fabricate the Upilex-S® type PI fiber, in which the rapid solidification of spinning dope and partial imidization take place simultaneously. Thus, the stability and mechanical strength of as-spun fibers can be improved, and the microvoids in fibers can be greatly reduced in relative to the wet-spun fibers. The resultant Upilex-S® type PI fiber shows higher tensile strength and modulus than most commercial thermal-oxidative polymeric fibers with an ultrahigh glass transition temperature Tg of 478 °C. Moreover, the WAXS and SAXS results indicate that orthorhombic crystals are formed for Upilex-S® type PI fiber in the post hot-drawing process. Increasing the hot-drawing temperature results in a continuous crystallization and high orientation of PI chains in amorphous phase and perfects the existing lamellar structure, which make a great contribution to the improved mechanical property.
Structural Changes and Electrodynamic Effects in Polymers under Fast Uniaxial Compression
Aleksey. I. Aleksandrov, Ivan A. Aleksandrov, Vitaliy G. Shevchenko, Aleksandr N. Ozerin
Corrected proof , doi: 10.1007/s10118-021-2511-5
[Abstract](319) [FullText HTML](177) [PDF 722KB](0)
Rheological explosion in polymers under uniaxial compression in an open volume occurs at the end of continuous rapid plastic deformation after several stages of creep. Two types of polymers were chosen for this study: brittle glassy amorphous polystyrene and thermoplastic semi-crystalline polypropylene. Electric pulses were detected during explosion, and their spectra were analyzed with two models. X-ray diffraction methods were used to investigate changes in the structure and morphology of polymers during deformation and rheological explosion. The pores appear in polymer in this process, and their shape and size distribution were derived from X-ray experiments. The main reason for the formation of pores in polymer samples in rheological explosion experiments is the intense microshifts in the polymer volume under the action of high applied pressure.
Synthesis and Pyrolysis of Soluble Cyclic Hf-Schiff Base Polymers
Yuhuan Wu, Li Ye, Yanan Sun, Weijian Han, Tong Zhao
Accepted Manuscript , doi: 10.1007/s10118-021-2566-3
[Abstract](2) [PDF 888KB](0)
Soluble Hf-containing polymers are significant processable precursors for the fabrication of ultra-high temperature ceramics. In this work, cyclic Hf-Schiff base polymers were synthesized via direct polymerization of hafnium alkoxide and bis-salen monomers. The defined structure and molecular weight of the polymers were characterized by NMR spectroscopy, gel permeation chromatography, and MALDI-TOF mass spectroscopy. The feed ratio of monomers regulated the molecular weight and solubility of the polymers. This synthetic strategy features simple operation under ambient conditions, efficient reaction with high yield, and producing cyclic polymers as main products. The Hf-Schiff base polymers were converted to HfC/C materials after pyrolysis under argon at 1600 C, identified by XRD measurements, elemental analyses, and Raman spectroscopy. This work will inspire more precise and efficient synthesis and applications of metallopolymers.
Enlarged Stable Phase Regime of Hybrid Lamella–Sphere Phase Enabled by A1B1A2(B2)m Branched Tetrablock Copolymer
Bin Zhao, Meijiao Liu, Chao Wang, Yingcai Chen, Yuci Xu
Accepted Manuscript , doi: 10.1007/s10118-021-2554-7
[Abstract](55) [PDF 2383KB](0)
Hybrid nanostructures show a great potential application in advanced nanotechnologies due to the anisotropic properties from different nanophases. Before, our previous work demonstrates that a linear A1B1A2B2 tetrablock copolymer of symmetric overall volume fraction can self-assemble into a hybrid lamella-sphere (LS) structure by tuning the relative length of the two A- blocks through self-consistent field theory(SCFT), where the spherical and the lamellar domains are mainly composed of the long A1- and short A2- blocks, respectively. However, the phase region of LS is limited. Aiming to expand the stable region of LS, we change the linear A1B1A2B2 copolymer to a branched A1B1A2(B2)m copolymer in order to increase the local spontaneous curvature between A2- and B2- blocks. We examine the impact of the branching number m of B2- block on the stable region of LS in the phase diagram with respect to fA1 and N for fixed fB = 0.5 and fB1 = 0.26, we find that m = 2 expands the LS region significantly in contrast to the linear architecture. While the stability window of LS does not change notably when m = 2 is increased to 3 in our calculated parameter space.
Recent advances on surface-modified biomaterials promoting selective adhesion and directional migration of cells
Chenxi Tu, Changyou Gao
Accepted Manuscript , doi: 10.1007/s10118-021-2564-5
[Abstract](64) [PDF 2609KB](0)
The surfaces and interfaces of biomaterials interact with the biological systems in multi-scale levels, and thereby influence the biological functions and comprehensive performance in vitro and in vivo. In particular, a surface promoting the selective adhesion and directional migration of desired types of cells in complex environment is extremely important in the repair and regeneration of tissues such as peripheral nerve and blood vessel, and long-term application of intracorporal devices such as intravascular implants. Therefore, surface modification of biomaterials is a facile and effective method to achieve the desired cell-biomaterials interactions. In this short review, recent advances on the surface modification of biomaterials to regulate selective cell adhesion and migration are briefly summarized. In particular, the surface properties of biomaterials are manipulated via the convenient introduction of amino groups to the ester-based polymers, the formation of polyelectrolyte multilayers, and the fabrication of topology and gradient cues, etc., followed by the association of chemical and biological signals such as collagen, heparin, hyaluronic acid, peptides and cell growth factors. The selective adhesion and directional migration of various types of cells such as endothelial cells (ECs), smooth muscle cells (SMCs), hepatocytes and Schwann cells (SCs) are achieved over the competitive counterpart cells by the use of cell-resisting substances and cell-selective motifs on gradient substrates in most cases. Recent works on cell behaviors in 3D cell-extracellular matrix (ECM)-mimicking substrates are also reviewed.
Influence of liquid isoprene rubber on strain softening of carbon black filled 1 isoprene rubber nanocomposites
Fengyi Hou, Yihu Song, Qiang Zheng
Accepted Manuscript , doi: 10.1007/s10118-021-2550-y
[Abstract](54) [PDF 8538KB](0)
The reinforcement of rubbers by nanoparticles is always accompanied with enhanced dissipation of mechanical energy upon large deformations. Methods for solving the contradiction between improving reinforcement and reducing energy dissipation for rubber nanocomposites have not been well developed. Herein carbon black (CB) filled isoprene rubber (IR)/liquid isoprene rubber (LR) blend nanocomposites with similar crosslink density (νe) are prepared and influence of LR on the strain softening behaviors including Payne effect under large amplitude shear deformation and Mullins effect under cyclic uniaxial deformation is investigated. The introduction of LR could improve the frequency sensitivity of loss modulus and reduce critical strain amplitude for Payne effect and loss modulus at the low amplitudes. Meanwhile, tuning νe and LR content allows reducing mechanical hysteresis in Mullins effect without significant impact on the mechanical performances. The investigation is illuminating for manufacturing nanocomposite vulcanizates with balanced mechanical hysteresis and reinforcement effect.
Effect and Mechanism of Solvent Properties on Solution Behavior and Films Condensed State Structure for the Semi-rigid Conjugated Polymers
Hao Zhang, Tao Li, Bin Liu, Tengning Ma, Long Huang, Zeming Bai, Dan Lu
Accepted Manuscript , doi: 10.1007/s10118-021-2555-6
[Abstract](52) [PDF 3008KB](0)
Solvents have an essential association with polymer solution behavior. However, few researches have been deeply done on this respect. In recent years, our research group focus on the study on effect of solvent properties on solution behavior and film condensed state structure for semi-rigid conjugated polymer up till to apply for optoelectronic device. Herein, influence of solvent properties including solubility of solvent, aromaticity, polarity and hydrogen bonds on semi-rigid polymer chain solution behavior, i.e., single chain conformation, chain shape, size and chains aggregated density were studied by means of static/dynamic laser light scattering (DLS/SLS) and exponential law etc. Effect of solvent properties on condensed state structure of the semi-rigid conjugated polymer film was studied by means of the spectra both UV absorption and PL as well as electron microscope etc. The essential reasons for the influence were discovered; and the mechanism was revealed. It was found solution behavior with different solvent properties had an essential physical relationship with chains condensed state structure of the semi-rigid conjugated polymers. More importantly, there was a quantitative structure-activity relationship between solution and film. The key to this relationship depended on the interaction between solvent molecules and the semi-rigid conjugated polymer chains. This interaction could also affect optoelectronic devices performance. This study is of great significance to effectively control the condensed state structure of the semi-rigid conjugated polymers in the process of dynamic evolution from solutions to films. It not only enriches the knowledge and understanding both semi-rigid conjugated polymer solution behaviors and film condensed state physics based on polymer physics but also is meaningful to practical application for conjugated polymer and other traditional polymers system.
Photoenzymatic RAFT Emulsion Polymerization with Oxygen Tolerance
Ruoyu Li and Zesheng An
Accepted Manuscript , doi: 10.1007/s10118-021-2556-5
[Abstract](59) [PDF 1259KB](0)
Photoenzymatic reversible addition-fragmenatation chain transfer (RAFT) emulsion polymerization, surfactant-free or ab initio, of various monomers is reported with oxygen tolerance. In surfactant-free emulsion polymerizatoin, poly(N,N-dimethylacrylamide)s were used as stabilizer blocks for emulsion polymerization of methyl acrylate, n-butyl acrylate and styrene, producing well-defined amphiphilic block copolymers, including those with an ultrahigh molecular weight, at quantitative conversions. The controlled character of surfactant-free emulsion polymerization was confirmed by kinetic studies, chain extension studies and GPC analyses. Temporal control was demonstrated by light ON/OFF experiments. In ab initio emulsion polymerization of methyl acrylate and methyl methacrylate, low-dispersity hydrophobic polymers were synthesized with predictable molecular weights. This study extends the monomer scope suitable for photoenzymatic RAFT polymerization from hydrophilic to hydrophobic monomers and demonstrates oxygen-tolerance can be equally achieved for emulsion polymerization with excellent RAFT control.
Preparation and Performance of HGM/PPENK-based High Temperature-Resistant Thermal Insulating Coatings
Lei Song, Li-Shuai Zong, Jin-Yan Wang, Xi-Gao Jian
Accepted Manuscript , doi: 10.1007/s10118-021-2551-x
[Abstract](51) [PDF 2202KB](0)
Novel high temperature-resistant coatings with high mechanical strength and thermal-insulating performance were prepared with PPENK resin as matrix and hollow glass microspheres (HGMs) as thermal-insulating filler. The corresponding mechanical and thermal-insulating study indicated that the mechanical properties of the coatings decreased with the increasing of HGM content, and improved after surface modification of HGM by KH570 resulting in enhancement of interaction between HGM and PPENK resin. The thermal conductivity of HGM/PPENK thermal-insulating coating decreased with the increase of HGM content and coating thickness, along with the decrease of the true density. It also showed slight increase trend due to HGMs surface modification. The HGM/PPENK coating filled with modified HGMs showed better thermal resistance than those of unmodified ones. The thermal decomposition temperature at 5% weight loss of the coating containing modified HGMs was 10 ℃ lower than that of pure PPENK, and 40 ℃ higher than that of the unmodified HGMs. The coating exhibited commendable appearance after 400 ℃ for 30 min. The merits of HGM/PPENK-based thermal coatings obviously demonstrated promising prospect in thermal protection fields.
Amphiphilic Graft Copolymers of Hydroxypropyl Cellulose Backbone with Nonpolar Polyisobutylene Branches
Jinrui Deng, Conglei Zhao, Zhitao Wei and Yixian Wu
Accepted Manuscript , doi: 10.1007/s10118-021-2546-7
[Abstract](53) [PDF 2479KB](0)
The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose (HPC) backbone and hydrophobic soft nonpolar polyisobutylene (PIB) branches have been successfully synthesized through nucleophile substitution reaction of living PIB chains carrying oxonium ion with the −OH groups along HPC backbone. The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB+/−OH molar ratio. The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromine end groups in the presence of AgClO4 and silver nanoparticles (3.2 ± 0.3 nm, 0.7−1.8 wt%) generated in-situ from AgBr. The phase-separation morphology formed in the graft copolymers due to their incompatibility from backbone and branches. The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches. The soft PIB segments in graft copolymers provided an unique surface via self-assembly for anti-protein adsorption against bovine serum albumin. A small amount of Ag nanoparticles in the copolymers contributed good antibacterial activities against Staphylococcus aureus or Escherichia coli.
Self-assembly of Amphiphilic Diblock Copolymers Induced by Liquid-Liquid Phase Separation
Jia-Lu Bai, Dan Liu, Rong Wang
Accepted Manuscript , doi: 10.1007/s10118-021-2563-6
[Abstract](77) [PDF 1675KB](3)
The liquid-liquid phase separation (LLPS) widely exists in biology, synthetic chemistry, crystallization kinetics and other fields, and it is very important to realize the related functions. The research on the competition between LLPS and micellization/vesiculation has made considerable progress. However, the way to effectively control the formation paths from homogeneous state to aggregates has not been completely solved, which is vital to dominate its structure and properties and even its future functions. Here we describe the phenomenon of LLPS and its effect on the dynamic process of self-assembly of amphiphilic diblock copolymers (BCPs). We focus on two variables, interaction parameters and concentration of BCPs. Starting from the establishment of phase diagram, we explore the existence conditions of LLPS state, the internal morphology and external size of large droplets, and its significant implications to the dynamic path of vesicle formation. Vesicles formed via LLPS have larger sized outer dimensions and inner cavities and contain more solvents during certain stages. The detailed research of LLPS and its self-assembly simulation has contributed to completing its theoretical basis and practical applications in the future in various fields.
Flexible Gradient poly(ether-ester) from the Copolymerization of Epoxides and ε-Caprolactone Mediated by a Hetero-bimetallic Complex
Wei-Min Ren, Hong-Juan Gao and Tian-Jun Yue
Accepted Manuscript , doi: 10.1007/s10118-021-2559-2
[Abstract](54) [PDF 1652KB](0)
Copolymerization is a commonly employed method to optimize the properties of polymer materials. Incorporating ether segments into polyesters main chain to obtain polyether-polyester copolymers is an effective strategy to realize the integration of multiple properties of polyester and polyether, and to develop more high-performance, multi-purpose polymer materials. Herein, the synthesis of poly(ether-ester)s is accessible by employing the biphenyl-linked heterodinuclear salen Cr-Al complex in the presence of PPNCl for the copolymerization of epoxides and ε-caprolactone (CL). Monitoring the copolymerization process reveals that the catalyst 1 exhibited good performance for the copolymerization of epoxides and CL, affording the copolymers with a gradient sequence structure. The dynamic thermomechanical analysis (DMA) study indicates the obtained poly(ether-ester)s possess enhanced flexibility, compared with the block copolymers or blend of PPO and PCL homopolymers with the same ratio. This study provides a theoretical basis for the preparation of high-performance polymer materials.
Structural evolution in flowing immiscible blends in the presence of rough particles: dependence of shear rate and blend ratio
Siying Xiang, Yinchun Yao, Miaomiao Lu, Yajiang Huang, Miqiu Kong, Guangxian Li
Accepted Manuscript , doi: 10.1007/s10118-021-2569-0
[Abstract](17) [PDF 2333KB](0)
The influence of polystyrene particles with different nanoscale roughnesses on the morphology of polyisobutylene/polydimethylsiloxane blends was studied under shear flow by using confocal laser scanning microscopy. It was found that the surface roughness of particles strongly affected their diffusion and distribution behaviors, thereby determining the size and spatial arrangement of droplets in the blends. The roughness effect of particles was found to possess a strong dependence both on the blend ratio and the shear rate. The result suggested that the particle roughness can serve as a new parameter to control the structure-property correlation in particle-filled polymer blends, especially under slow flow.
Effect of 1, 8-Diiodooctane Content on the Performance of P3HT:PC61BM Bulk Heterojunction Photodetectors
Xin Wang, Shi-Jia Gao, Jin-Feng Han, Yu-Lin Zhang, Sai Zhang, Wen-Qiang Qiao, and Zhi-Yuan Wang
Accepted Manuscript , doi: 10.1007/s10118-021-2548-5
[Abstract](60) [PDF 1599KB](0)
A series of polymer photodetectors with device configuration of ITO/PEDOT:PSS/P3HT:PC61BM/C60/Al were prepared by using P3HT as the donor material and PC61BM as the acceptor material. By regulating the content of 1, 8-diiodooctane (DIO) (v/v: 1%, 3%, 5%) as a processing additive, the morphology of the active layer can be greatly improved. With C60 as the hole blocking layer, the dark current density of the device can be reduced by about an order of magnitude. When employing 3 % DIO (v/v) in the active layer processing, the photodetetcors present the best performance, the detectivity of the device is 1.52×1012 Jones at 540 nm under a bias of -0.1 V. Moreover, it also has a wider linear dynamic range of 60 dB as well as faster response speed (τr/τf = 0.53/0.71 μs) than that of devices with other content of DIO additives.
Improving impact toughness of polylactide/ethylene-co-vinyl-acetate blends via adding fumed silica nanoparticles: Effects of specific surface area dependent selective distribution of silica
Ting-ting Zhang, Mei-xi Zhou, Zhen-you Guo, You-bo Zhao, Di Han, Hao Xiu, Hong-wei Bai, Qin Zhang, Qiang Fu
Accepted Manuscript , doi: 10.1007/s10118-021-2565-4
[Abstract](66) [PDF 1920KB](0)
Adding fumed silica (SiO2) has been considered as an effective method to tailor the phase morphology and performance of elastomer-toughened plastic binary blends. It has been demonstrated that the selective distribution of SiO2 plays a decisive role in the mechanical properties, especially the impact toughness, of plastic/elastomer/SiO2 nanocomposites. In this work, we aim to illuminate the role of specific surface area in controlling their selective distribution of fumed SiO2 and consequent mechanical properties of plastic/elastomer binary blends. Three types of SiO2 with different specific surface areas were incorporated into polylactide/ethylene-co-vinyl-acetate (PLA/EVA) model blends by melt blending directly. It was found that the selective distribution of SiO2 is largely determined by their specific surface areas, i.e. SiO2 nanoparticles with low specific surface area has a stronger tendency to be located at the interface between PLA matrix and EVA dispersed phase as compared to those with high specific surface area. The specific surface area dependent interfacial selective distribution of SiO2 is mainly attributed to the extent of increased viscosity of EVA dispersed phase in which SiO2 nanoparticles are initially dispersed and resultant migration rate of SiO2 nanoparticles. The interfacial localized SiO2 nanoparticles induce an obvious enhancement in the impact toughness with strength and modulus well maintained. More importantly, in the case of same interfacial distribution, toughening efficiency is increased with the specific surface area of SiO2. Therefore, this is an optimum specific surface area of SiO2 for the toughening. This work not only provides a novel way to manipulate the selective distribution of SiO2 in elastomer-toughened plastic blends toward high-performance, but also give a deep insight into the role of interfacial localized nanoparticles in the toughening mechanism.
Finely Tuned Electron/Hole Transport Preference of Thiazoloisoindigo- based Conjugated Polymers by Incorporation of Heavy Chalcogenophenes
Chen-Chen Li, Miao Xiong, Jia-Wei Peng, Jie-Yu Wang, Huan-Rui Zhang, You-Bing Mu, Jian Pei and Xiao-Bo Wan
Accepted Manuscript , doi: 10.1007/s10118-021-2552-9
[Abstract](61) [PDF 1771KB](0)
A series of copolymers of thiazoloisoindigo (TzII) with different chalcogenophene trimers were synthesized to systematically investigate the chalcogen effect on their charge transport properties. When only the middle thiophene ring of terthiphene (T-T-T) is replaced by heavier chalcogenophenes, a preference (expressed by the ratio of me/mh) towards electron transport was observed descending from T-T-T to T-Se-T then to T-Te-T (Se and Te stand for selenophene and tellurophene, respectively). On the other hand, with the increased number of heavier chalcogenophenes, a preference toward hole transport was observed descending from Se-T-Se to Se-Se-Se then to Se-Te-Se. This phenomenon is well-explained by the balance between the aromatic resonance energy of the chalcogenophenes and the electronegativity of the chalcogens. Specifically, P(TzII-T-Se-T) displayed relatively balanced ambipolar property (mhmax and memax of 3.77 and 1.59 cm2 V-1 s-1 with a me/mh of 0.42), while P(TzII-Se-Te-Se) exhibited the best preference to hole transfer with a me/mh of 0.09. P(TzII-T-Te-T) exhibited the best preference to electron transfer with a me/mh of 16 and the memax of 0.64 cm2 V-1 s-1 which is the highest electron mobility among the known conjugated polymers containing tellurophenes.
Local Transient Jamming in Stress Relaxation of Bulk Amorphous Polymers
Jiping Wang, Yihuan Yu, Yaqian Guo, Wen Luo, Wenbing Hu
Accepted Manuscript , doi: 10.1007/s10118-021-2570-7
[Abstract](15) [PDF 1979KB](0)
Bulk amorphous polymers become stretched and parallel-aligned under loading stress, and their intermolecular cooperation slows down the subsequent stress relaxation process. By means of dynamic Monte Carlo simulations, we employed the linear viscoelastic Maxwell model for stress relaxation of single polymers and investigated their intermolecular cooperation in the stress relaxation process of stretched and parallel-aligned bulk amorphous polymers. We made the thermal fluctuation analysis on the reproduced Debye relaxation and Arrhenius fluid behaviors of bulk polymers. We found a transient state with stretch-coil coexistence among polymers in the stress relaxation process. Further structure analysis revealed a scenario of local jamming at the transient state, raising an entropy barrier for stretch-coil transition of partial polymers. The microscopic mechanism of intermolecular cooperation appears as unique to polymer stress relaxation, which interprets the hydrodynamic interactions as one of essential factors raising a high viscosity in bulk amorphous polymers. Our simulations set up a platform of molecular modeling in the study of polymer stress relaxation, which brought new insights into polymer dynamics and the related mechanical/rheological properties.
Benzosuberyl Substituents as a "Sandwich-Like" Function in Olefin Polymerization Catalysis
Yu-Yin Wang, Chao-Qun Wang, Xiao-Qiang Hu, Yan Xia, a Yue Chi, Yi-Xin Zhang, and Zhong-Bao Jian
Accepted Manuscript , doi: 10.1007/s10118-021-2562-7
[Abstract](49) [PDF 1628KB](0)
For the rational design of metal catalyst in olefin polymerization catalysis, various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center, among which the ”sandwich” type turned out to be an efficient category in achieving high molecular weight polyolefin. In the α-diimine system, the “sandwich” type catalysts were built using the typical 8-aryl-naphthyl framework. In this contribution, by introducing the rotationally restrained benzosuberyl substituent into the ortho- position of N-aryl rings, a new class of “sandwich-like” -diimine nickel catalysts was constructed and fully identified. The rotationally restrained benzosuberyl substituents played a “sandwich-like” function by capping the nickel center from two axial sites. Compared to the nickel catalyst Ni1 bearing freely rotated benzhydryl substituent, Ni2 featuring benzosuberyl substituent enabled the increase (8 times) of polymer molecular weights from 8 kDa to 65 kDa in the polymerization of ethylene. By further increasing the steric bulk of another ortho- site of the N-aryl ring, the polymer molecular weight even reached an ultrahigh level of 833 kDa (Mw = 1857 kDa) using the optimized Ni3. Notably, these nickel catalysts could also mediate the copolymerization of ethylene with methyl 10-undecenoate, with Ni3 giving the highest copolymer molecular weight (88 kDa) and the highest incorporation of comonmer (2.0 mol%), along with high activity of up to 105 g mol−1 h−1.
Fabrication of highly anisotropic and interconnected porous scaffolds to promote preosteoblast proliferation for bone tissue engineering
Ya-Hui Liu, Wei Liu, Zi-Li Zheng, Xin Wei, Nouman Ali Shah, Hao Lin, Baisong Zhao, Shishu Huang, Jia-Zhuang Xu, Zhong-Ming Li
Accepted Manuscript , doi: 10.1007/s10118-021-2573-4
[Abstract](0) [PDF 2407KB](0)
Mimicking the complex structure of natural bone remains a challenge for bone tissue scaffolds. In this study, a novel processing strategy was developed to prepare the bone-like scaffolds that are featured by highly oriented and fully interconnected pores. This type of biomimetic scaffolds was evolved from solid phase stretching of immiscible polycaprolactone (PCL)/polyethylene oxide (PEO) blends with cocontinuous structure and the pore morphology was inherited from selective extraction of water soluble PEO phase. The pore anisotropy was readily tuned by varying the stretching strain without loss of interconnectivity. Significant promotion in preosteoblast proliferation, alkaline phosphatase activity and osteogenic gene expression was observed in the oriented porous scaffolds compared to the isotropic porous counterpart. The oriented architecture provided a topographical cue for aligned growth of preosteoblasts, which activated the Wnt/β-catenin signaling pathway. The proposed strategy enriches the toolbox for the scaffold design and fabrication for bone tissue engineering.
Nanomechanical and Chemical Mapping of the Structure and Interfacial Properties in Immiscible Ternary Polymer Systems
Haoxuan Li, Thomas P. Russell and Dong Wang
Accepted Manuscript , doi: 10.1007/s10118-021-2567-2
[Abstract](54) [PDF 1958KB](0)
It is a challenge to identify each phase in a multi-component polymer system and uniquely determine the interfacial properties between the different phases. Using atomic force microscopy nanomechanical mapping (AFM-NM) and AFM-based infrared spectroscopy (AFM-IR), we identify each phase, visualize structural developments, and determine the interfacial properties in a blend of three polymers: high-density polyethylene (HDPE), polyamide (PA6), and poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS). Each phase can be identified from the Young’s modulus, along with the structural development within the phases before and after compatibilization. The interfacial width between HDPE/PA6, HDPE/SEBS, and SEBS/PA6 were determined independently in one measurement from a Young’s modulus map. The structural, mechanical property development and identity of the phases were determined by AFM-NM, while AFM-IR, providing complementary chemical information, identified interfacial reactions, showed the chemical affinity of a compatibilizer with the component phases, and mapped the distribution of the compatibilizer in the ternary polymer blends. The chemical, structural and interfacial information obtained by these measurements provide information that is essential for producing mechanically robust materials from incompatible mixtures of polymers.
Effect of Exogenous Carboxyl and Hydroxyl Groups on Pyrolysis Reaction of High Molecular Weight Poly(L-Lactide) under the Catalysis of Tin
Li-dong Feng, Xin-chao Bian, Gao Li, Xue-si Chen
Accepted Manuscript , doi: 10.1007/s10118-021-2557-4
[Abstract](48) [PDF 2251KB](0)
The effect of exogenous hydroxyl, carboxyl groups and/or Sn2+ on pyrolysis reactions of poly(L-lactide) (PLLA) was investigated by thermogravimetric analysis (TGA). The activation energy (Ea) of pyrolysis reactions was estimated by the Kissinger–Akahira–Sunose method. The kinetic models were also explored by the Malek method, and the random degradation behavior was determined by comparing the plots of ln⁡{-ln⁡〖[1-(1-w)^0.5 ]}〗 vs. 1/T for experimental data from TGA with model reactions. The pyrolysis reaction rate of PLLA was affected slightly by exogenous hydroxyl and carboxyl groups at lower levels of Sn with 65-70 ppm but increased appreciably in the presence of extraneous Sn2+, –COOH/Sn2+, or –OH/Sn2+. The Ea values for the pyrolysis reactions of the PLLAs that provided lactide were different under the catalysis of Sn2+ in different chemical environments because Sn2+ can form the new Sn-carboxylate and Sn-alkoxide with exogenous carboxyl and hydroxyl groups, which were different in steric hindrance for the formation of activated complex between Sn2+ and PLLA. Under the catalysis of Sn2+, a lactide molecule can be directly eliminated selectively at a random position of PLLA molecular chains, and the molecular chain of PLLA cannot change two PLLA fragments at the elimination site of lactide. However, it was regenerated into a new PLLA molecule with the molecular weight reduced by 144 g·mol-1.
Facile and large-scale fabrication of self-crimping elastic fibers for large strain sensors
Jin-Chao Yu, Kang Chen, Hong Ji, Yang Zhang, Yu-Mei Zhang, Zhi-Juan Pan
Accepted Manuscript , doi: 10.1007/s10118-021-2560-1
[Abstract](51) [PDF 1861KB](0)
Stretchable conductive fibers offer unparalleled advantages in the development of wearable strain sensors for smart textiles due to their excellent flexibility and weaveability. However, the practical applications of these fibers in wearable devices are hindered by either contradictory properties of conductive fibers (high stretchability versus high sensing stability), or lack of manufacturing scalability. Herein, we present a facile approach for highly stretchable self-crimping fiber strain sensors based on a polyether-ester (TPEE) elastomer matrix using a side-by-side bicomponent melt-spinning process involving two parallel but attached components with different shrinkage properties. The TPEE component serves as a highly elastic mechanical support layer within the bicomponent fibers, while the conductive component (E-TPEE) of carbon black (CB), multiwalled carbon nanotubes (MCNTs) and TPEE works as a strain-sensitive layer. In addition to the intrinsic elasticity of the matrix, the TPEE/E-TPEE bicomponent fibers present an excellent form of elasticity due to self-crimping. The self-crimping elongation of the fibers can provide a large deformation, and after the crimp disappears, the intrinsic elastic deformation is responsible for monitoring the strain sensing. The reliable strain sensing range of the TPEE/E-TPEE composite fibers was 160~270% and could be regulated by adjusting the crimp structure. More importantly, the TPEE/E-TPEE fibers had a diameter of 30~40 μm and tenacity of 40~50 MPa, showing the necessary practicality. This work introduces new possibilities for fiber strain sensors produced in standard industrial spinning machines.
Metal-free Synthesis of Pyridyl Conjugated Microporous Polymers for Photocatalytic Hydrogen Evolution
Qin-ruo Zeng, Zhong-hua Cheng, Chen Yang, Yan He, Nan Meng, Charl F. J. Faul, Yao-zu Liao
Accepted Manuscript , doi: 10.1007/s10118-021-2574-3
[Abstract](0) [PDF 1638KB](0)
Developing efficient, stable and sustainable photocatalysts for water splitting is one of the most significant methods to generate hydrogen. Conjugated microporous polymers, as a new type of organic semiconductor photocatalyst, have adjustable bandgaps and high specific surface areas, and can be synthesized using diverse methods. In this work, we report the design and synthesis of a series of pyridyl conjugated microporous polymers (PCMPs) utilizing polycondensation of aromatic aldehydes and aromatic ketones in the presence of ammonium acetate. PCMPs with different chemical structures were synthesized via adjusting monomers with different geometry and content of nitrogen element, which adjusts the bandgap and photocatalytic performance. Photocatalytic hydrogen evolution rate (HER) up to 1198.9 μmol·h-1·g-1 was achieved on the optimized polymer with a specific surface area of 312 m2·g-1 under UV–vis light irradiation (λ>320 nm). This metal-free synthetic method provides a new avenue to prepare an efficient photocatalyst for hydrogen evolution.
Injectable Hyaluronic Acid/Poly(γ-Glutamic Acid) Hydrogel with Step-by-Step Tunable Properties for Soft Tissue Engineering
Xue-Bin Ma, Rong Yang, Kanaparedu P. C. Sekhar, Bo Chi
Accepted Manuscript , doi: 10.1007/s10118-021-2558-3
[Abstract](50) [PDF 1679KB](0)
Injectable hydrogels as an important class of biomaterials have gained much attention in tissue engineering. However, their crosslinking degree is difficult to be controlled after being injected into body. As we all know, the crosslinking degree strongly influences the physicochemical properties of hydrogels. Therefore, developing an injectable hydrogel with tunable crosslinking degree in vivo is important for tissue engineering. Herein, we present a dual crosslinking strategy to prepare injectable hydrogels with step-by-step tunable crosslinking degree using Schiff base reaction and photopolymerization. The developed hyaluronic acid/poly(γ-glutamic acid) (HA/γ-PGA) hydrogels exhibit step-by-step tunable swelling behavior, enzymatic degradation behavior and mechanical properties. Mechanical performance tests show that the storage moduli of HA/γ-PGA hydrogels are all less 2000 Pa and the compressive moduli are in kilopascal, which have a good matching with soft tissue. In addition, NIH 3T3 cells encapsulated in HA/γ-PGA hydrogel exhibit a high cell viability, indicating a good cytocompatibility of HA/γ-PGA hydrogel. Therefore, the developed HA/γ-PGA hydrogel as an injectable biomaterial has a good potential in soft tissue engineering.
Interfacial improvement of carbon fiber/epoxy composites by incorporating superior and versatile multiscale gradient modulus intermediate layer with rigid-flexible hierarchical structure
Peifeng Feng, Guojun Song, Wenjian Zhang, Hao Zheng, Bowen Li, Shaofeng Zhou, Yaqing Liu, Guangshun Wu, Lichun Ma
Accepted Manuscript , doi: 10.1007/s10118-021-2549-4
[Abstract](50) [PDF 1916KB](0)
In order to enhance the interfacial adhesion of carbon fiber (CF) and polymer matrix, a multiscale gradient modulus intermediate layer with rigid-flexible (GO-PA) hierarchical structure was designed and fabricated between CFs and matrix by a facile and businesslike strategy. The polarity, roughness and wettability of CFs surface as well as the thickness of intermediate layer in composite have been significantly increased after rigid-flexible hierarchical structure constructing. The IFSS, ILSS, compression and impact toughness manifested that the hierarchical structure could bring about a fantastic improvement (76.8%, 46.4% 40.7% and 37.8%) for the interfacial and mechanical properties than other previous reports. Consequently, the establishment of CF surface with gradient modulus rigid-flexible hierarchical structure via regulation of nanoparticles and polymer array would open a new, viable and promising route for obtaining high-performance composites.
Transport of Propylene Carbonate-LiTFSI Electrolytes in P(VDF-HFP) using Time-Resolved ATR-FTIR Spectroscopy: Diffusion Coefficients and Molecular Interactions
Huixian Li, Lei Hou and Peiyi Wu
Accepted Manuscript , doi: 10.1007/s10118-021-2571-6
[Abstract](0) [PDF 24844KB](0)
The time-resolved attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is employed to investigated the transport mechanism of gel electrolytes by monitoring the diffusion behavior of propylene carbonate-lithium bis(trifluoromethylsulfonyl)imide (PC-LiTFSI) solution through poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) films. Fickian behavior has been observed for both TFSI- and PC. Higher temperature leads to faster diffusion of TFSI- and PC, which could be related to the increased free volume in P(VDF-HFP) matrix and rapid molecular movements upon heating. Various molecular interactions among LiTFSI, PC and P(VDF-HFP) have been recognized. During the diffusion process, PC molecules, in the form of small clusters, can firstly diffuse through the P(VDF-HFP) film and interact with P(VDF-HFP) by dipole-dipole interaction, acting as the plasticizer. Then, Li+ diffuses into P(VDF-HFP) with the help of ion-dipole interactions between Li+ and C=O of PC. Meanwhile, TFSI- diffuses through the polymer matrix in solvation states. In addition, slight ion-dipole interactions between Li+ and P(VDF-HFP) have been observed as well. Results in this work contribute to a better understanding of transport process in gel polymer electrolytes for lithium-ion batteries and support the development of improved gel polymer electrolytes by rationally regulating molecular interactions.
Functional Amphiphilic Poly(2-oxazoline) Block Copolymers as Drug Carriers: the Relationship Between Structure and Drug Loading Capacity
Si Dong, Sheng Ma, Zhilin Liu, Lili Ma, Yu Zhang, Zhaohui Tang, Mingxiao Deng, Wantong Song
Accepted Manuscript , doi: 10.1007/s10118-021-2547-6
[Abstract](61) [PDF 3921KB](0)
Poly(2-oxazoline) (POx) is a kind of polymeric amides that can be viewed as conformational isomers of polypeptides with excellent cyto-and hemo-compatibility, and is promising to be used as drug carriers. However, the drug loading capacity (DLC) of POx for many drugs is still low except several hydrophobic ones including paclitaxel (PTX). Herein, we prepared a series of amphiphilic POx block copolymers with varies functional groups, and investigated the relationship between functional structures and the DLC. Functional POxs with benzyl, carboxyl, and amino groups in the side-chain were synthesized based on a poly(2-methyl-2-oxazoline)-block-poly (2-butyl-2-oxazoline-co-2-butenyl-2-oxazoline) (PMeOx-P(nBuOx-co-ButenOx), PMBEOx) precursor, followed by click reaction between vinyl and the 2-phenylethanethiol, thioglycolic acid, and cysteamine. Using thin-film method, eight commonly used drugs with various characters were encapsulated within these functional POx polymers. We found that amine-containing drugs were more easily encapsulated by POx with carboxyl groups, while the existence of amine in POx enhanced the loading capacity of drugs with carboxyl groups. In addition, π–π interaction resulted inenhanced DLC of most drugs, except several hydrophobic drugs with a aromatic to total carbon ratio less than 0.5. In general, we could successfully encapsulate all the selected drugs with a DLC% over 10 % using properly selected functional POxs. The above results confirm that the DLC of polymeric carriers can be adjusted by modifying the functional groups, and the prepared series of functional POxs provide an option for various drug loading.
Construction of Supramolecular Chirality in Polymer Systems: Chiral Induction, Transfer and Application
Xiao-Xiao Cheng, Teng-Fei Miao, Lu Yin, Wei Zhang, and Xiu-Lin Zhu
Accepted Manuscript , doi: 10.1007/s10118-021-2561-8
[Abstract](65) [PDF 2578KB](0)
Chirality, commonly found in organisms, biomolecules, and nature such as L-amino acids and D-sugars, has been extensively studied in chemistry and biomedical science. Hence, the demand for simple and efficient construction of chiral structures, especially chiral polymers, have been rapidly growing due to their potential applications in chemosensors, asymmetric catalysis, and biological materials. However, most chiral polymers reported are prepared directly from chiral monomers/chiral catalysts, the corresponding strategy usually involves tedious and expensive design and synthesis. Fortunately, chirality induction strategies (such as circularly polarized light, chiral solvation, and chiral gelation etc.) have been known to be highly versatile and efficient in producing chirality from achiral polymers. In this feature article, the current research on chirality induction, transfer and application in achiral polymer systems is summarized. Furthermore, this article discusses some basic concepts, seminal studies, recent advances, the structural design principles, as well as perspectives in the construction and applications of chiral polymers derived from achiral monomers, with the hope to attract more interest from researchers and further advance the development of chiral chemistry.
Polymer Nanocomposites in Sensor Applications: A Review on Present Trends and Future Scope
Prashant Shukla and Pooja Saxena
Accepted Manuscript , doi: 10.1007/s10118-021-2553-8
[Abstract](75) [PDF 2520KB](0)
Polymers are crucial constituent of modern electronic devices. They can be used in their pristine, composite or nanocomposite form for several domestic and industrial applications with innumerable unique possibilities. Polymer nanocomposites have gained a wide theoretical interest and numerous practical applications in diverse veins of science and technology as they bestow the materials not only with virtuous processability but also exceptional functionalities. It is evidenced that the electrical conductance of the polymer nanocomposite is governed by the conductive filler networks within the polymer matrix. Henceforth, insignificant variation in the conductive networks can result in noteworthy variations in the output electric signal of the polymer nanocomposite. Exploiting this stimuli-responsive performance of conductive networks to the physical parameters, polymer nanocomposites can be harnessed to fabricate novel sensitive sensors to detect vital physical parameters viz. strain/stress, pressure, temperature, solvent or vapor. However, technical and phenomenological studies on polymer nanocomposites are still enduring. Advanced explanations are being sought but the mechanisms governing the formation of several polymer nanocomposites is still a topic of debate in the material science community. Their in-depth investigation requires copious scientific work. This review analytically sketches the synthesis, microstructures, physiochemical properties, and the underlying mechanisms for stimuli-responsiveness to the physical parameters of the polymer nanocomposites as well as their applications in various sensitive sensors and detectors. Thus, it became evocative for this review article to focus on their processing methodologies, physiochemical physiognomies, classification and probable potentials of polymer nanocomposites. This review article primarily presents the current literature survey on polymer composites and also the gap areas in the study encourages the objective of the present review article. Finally, the present status and perspectives as well as the advantages of specific polymer nanocomposites are summarised. The attention of this review article is drawn to the present trends, challenges and future scope under lying in this field of study. Lastly, the vital concern and future challenge in utilizing the stimulus responsive behavior of polymer nanocomposites to design versatile sensors for real time applications are elaborately discussed.
Feasible Fabrication of Hollow Micro-vesicles by Non-amphiphilic Macromolecules Based on Interfacial Cononsolvency
Jing-Hong Wang, Rui Chen, Zi-Qing Zhao, Jie Shen, He Yang, Yan Luo, Gao-Jian Chen, Hong Chen, and John L. Brash
Accepted Manuscript , doi: 10.1007/s10118-021-2541-z
[Abstract](54) [PDF 1561KB](0)
Herein we present a new perspective showing that water-soluble liquids, when added to water, undergo transient emulsification before completely dissolving. Thus, non-amphiphilic macromolecules can self-assemble at the two-miscible-phase interface when cononsolvent effect appears. A representative case shown here is that when poly(N-isopropylacrylamide) (PNIPAm), prepared by aqueous radical polymerization, in methanol solution is added to water, the polymer chains rapidly self-assemble into hollow micro-vesicles based on the cononsolvency at water/methanol interface. This finding provides a subtle strategy to prepare hollow micro-vesicles by non-amphiphilic polymers without template participating. And a new concept “interfacial cononsolvency” is proposed to explain its formation process. Due to the easy modification process, sugar-contained PNIPAm chains are synthesized by copolymerization. As an application example, we show that these sugar-contained PNIPAm chains can be further made into “sweet” micro-vesicles (containing glucose residues). And the “sweet” micro-vesicles can well mimick the protocells which are involved in the recognition of bacteria.

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2021, 39(4) .  
[Abstract](85) [FullText HTML](57) [PDF 9852KB](2)
Macroscopic Regulation of Hierarchical Nanostructures in Liquid-crystalline Block Copolymers towards Functional Materials
Feng Cai, Yu-Xuan Chen, Wen-Zhong Wang, Hai-Feng Yu
2021, 39(4): 397 -416.   doi: 10.1007/s10118-021-2531-1
[Abstract](568) [FullText HTML](143) [PDF 1894KB](0)
The great potential of liquid-crystalline block copolymers (LCBCs) containing photoresponsive mesogens toward novel applications in photonics and nanotechnology has been attracting increasing attention, due to the combination of the inherent property of microphase separation of block copolymers and the hierarchically-assembled structures of liquid-crystalline polymers (LCPs). The periodically ordered nanostructures in bulk film of LCBCs can be acquired by supramolecular cooperative motion, derived from the interaction between liquid-crystalline elastic deformation and microphase separation, which are able to improve physical properties of polymer film toward advanced functional applications. Moreover, various micro/nano-patterned structures have been fabricated via light manipulation of photoresponsive LCBCs with good reproducibility and mass production. Thanks to recent developments in synthesis and polymerization techniques, diverse azobenzene-containing LCBCs have been designed, resulting in the creation of a wide variety of novel functions. This review illustrates recent progresses in macroscopic regulation of hierarchical nanostructures in LCBCs towards functional materials. The existing challenges are also discussed, showing perspectives for future studies.
Azobenzene Based Photo-responsive Mechanical Actuator Fabricated by Intermolecular H-bond Interaction
Chun-Yan Yu, Jia-Hui Mu, Yun-Lei Fu, Yun-Chao Zhang, Ji-Shu Han, Rui-Yang Zhao, Jia Zhao, Zi-Hao Wang, Zhong-Cheng Zhao, Wei-Jun Li, Fu-Sheng Liu
2021, 39(4): 417 -424.   doi: 10.1007/s10118-021-2504-4
[Abstract](513) [FullText HTML](211) [PDF 637KB](1)
Photo-responsive mechanical actuator is a class of stimuli-responsive materials transferring light to mechanical energy through macroscopic transformation. To fabricate photo-responsive mechanical actuator, soft polymeric materials crosslinked with functional bridging structures are desired. Supramolecular interaction is a relatively common way to fabricate crosslinked materials due to its excellent self-assembly performance. And azobenzene and derivatives are ideal candidates of photo-responsive materials because of the unique photo-induced trans-cis isomerization. Here, a new kind of crosslinked materials based on supramolecular interaction between 4,4'-dihydroxyazobenzene and chitosan is reported. Under 355 nm irradiation, the macroscopic bending of polymeric materials occurs rapidly due to the photo-isomerization of 4,4'-dihydroxyazobenzene. Meanwhile, the photo-responsive mechanical actuator can also lift weight which is up to 200 times that of the actuator itself, and convert energy from light to mechanical work efficiently. This report suggests a new kind of photo-responsive actuator based on supramolecular interaction and may be helpful to contribute a theoretical basis to the design and synthesis of photo-responsive mechanical actuator suitable for large-scale manufacturing industrialization in future.
Robust and Self-healable Antibiofilm Multilayer Coatings
Chao Zhou, Jun-Tao Zhou, Cheng-Ju Sheng, Dicky Pranantyo, Yan Pan, Xiao-Jia Huang
2021, 39(4): 425 -440.   doi: 10.1007/s10118-021-2513-3
[Abstract](360) [FullText HTML](245) [PDF 11625KB](0)
The infection induced by implantation of biomedical materials may result from the biofilm formation after bacteria attachment. Hence, the antibiofilm surface coating represents a novel technique to improve the antibacterial activity of biomedical materials. The traditional antibiofilm surface coatings exhibited some disadvantages and provided a limited service life. In this work, we used polyethyleneimine grafted 3-maleimidopropionic acid (PEIM) and poly(acrylic acid) grafted 2-furfurylamine (PAAF) to achieve robust and self-healable crosslinked multilayer coatings, employing Layer-by-Layer (LbL) self-assembly technique and Diels-Alder reaction. Then, thiol-terminated poly((3-acrylamidopropyl) trimethylammonium chloride) (PAMPTMA-SH) was grafted onto the crosslinked multilayer coating by thiol-ene click reaction to form a novel multilayer coating (PEIM/PAAF)10-PAMPTMA. We found that this coating showed robust and self-healable activity, and significantly inhibited the bacterial growth and biofilm formation after infection with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by in vitro and in vivo assays for 120 h. In addition, the multilayer coating did not induce significant hemolysis or affect the cell viability of red blood cells. In vivo studies also showed that (PEIM/PAAF)10-PAMPTMA coating efficiently blocked the infiltration of inflammatory cells and gene expression in the mouse skin challenged with E. coli or S. aureus. Taken together, these results showed that the prepared multilayer coating exhibited strong antibiofilm activity and provided a new strategy for the application of highly efficient antibiofilm surface coating of biomedical materials.
Platinum Atoms Dispersed in Single-chain Polymer Nanoparticles
Zhi-Yu Hu, Hong-Ting Pu, Jian-Guo Wu
2021, 39(4): 441 -446.   doi: 10.1007/s10118-021-2499-x
[Abstract](439) [FullText HTML](146) [PDF 756KB](0)
The intramolecular cross-linking of single polymer chains can form single-chain nanoparticles (SCNPs), which have many applications. In this study, styrenic copolymers with pendent triphenylphosphine as the coordination site for platinum ions (Pt(II)) and benzocyclobutene as the latent reactive groups are synthesized. Triphenylphosphine groups in the chains can coordinate Pt(II) and aid slight single-chain folding in dilute solution. The intramolecular cross-linking caused by the ring-open reaction of benzocyclobutene completes the single-chain collapse and forms stable SCNPs in dilute solution. Pt(II) embedded in SCNPs can be further reduced to platinum atoms (Pt(0)). Pt(0) steadily and atomically dispersed in SCNPs exhibits better catalytic properties than normal polymer carried platinum particles do for the reduction of p-nitrophenol to p-aminophenol.
Styrene-containing Phosphine-sulfonate Ligands for Nickel- and Palladium-catalyzed Ethylene Polymerization
Shabnam Behzadi, Chen Zou, Bang-Pei Yang, Chen Tan, Chang-Le Chen
2021, 39(4): 447 -454.   doi: 10.1007/s10118-021-2509-z
[Abstract](780) [FullText HTML](242) [PDF 409KB](1)
A series of phosphine-sulfonate ligands bearing 2-, 3- and 4-vinylphenyl on the phosphorus atom were designed, synthesized, characterized and investigated in Ni- and Pd-catalyzed ethylene polymerization. The structure of the phosphine-sulfonate Pd complex bearing 2-vinylphenyl on the phosphorus atom showed 2,1-insertion for the 2-vinyl group. The phosphine-sulfonate Ni complex bearing 2-vinylphenyl resulted in significantly increased thermal stability and polyethylene molecular weights (Mn=3.69×104 g·mol−1 at 80 °C) versus the counterparts bearing 3-/4-vinyl groups as well as previously reported phosphine-sulfonate Ni complexes bearing bulky biaryl substituents.
Highly Transparent and Colorless Polyimide Film with Low Dielectric Constant by Introducing Meta-substituted Structure and Trifluoromethyl Groups
Hong-Tao Zuo, Feng Gan, Jie Dong, Peng Zhang, Xin Zhao, Qing-Hua Zhang
2021, 39(4): 455 -464.   doi: 10.1007/s10118-021-2514-2
[Abstract](235) [FullText HTML](212) [PDF 726KB](0)
An effective design strategy for preparing highly transparent polyimide film with low dielectric constant is presented. The key to the strategy is to simultaneously introduce meta-substituted structure and trifluoromethyl in polymer chains. By using this design strategy, a highly transparent polyimide film with low-k was synthesized from 3,5-diaminobenzotrifluoride (m-TFPDA) and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) through a two-step method. The obtained m-TFPDA/6FDA (CPI) film (~30 μm) possesses high optical transparency (λcutoff=334 nm, T450nm=85.26%, Haze=0.31) and is close to colorless (L*=96.03, a*=−0.34, b*=2.12, yellow index=3.96). The intrinsic k and dielectric loss value of the film are 2.27 and 0.0013 at 10 kHz, respectively. More importantly, such low dielectric performance could remain stable up to 280 °C, and the film shows a low moisture rate (~0.51%), which helps to maintain the low-k property stability in different humid environments. Meanwhile, the film also shows good thermal stability and mechanical properties, with a glass transition temperature (Tg) of 296 °C and the 5 wt% decomposition temperature (Td,5%) of 522 °C under N2. The tensile strength and tensile modulus of the film are 85.1 MPa and 1.96 GPa, respectively. In addition, the film is soluble in common solvents, which allows simple solution processing and low-cost, continuous roll-to-roll processes. This design strategy is beneficial to improving the transparency, lightening yellow color, lowering the dielectric constant and meanwhile maintaining the comprehensive properties of polyimide films, which is mainly due to the introduced meta-substituted and trifluoromethyl structures effectively inhibiting the transfer of charge transfer complex (CTC) effects and increasing the free volume of film. This design strategy could also be extended to other high-performance polymer systems.
The Relationship between Pendant Phosphate Groups and Mechanical Properties of Polyisoprene Rubber
Shi-Qi Li, Mao-Zhu Tang, Cheng Huang, Rong Zhang, Guang-Su Huang, Yun-Xiang Xu
2021, 39(4): 465 -473.   doi: 10.1007/s10118-021-2497-z
[Abstract](307) [FullText HTML](194) [PDF 1233KB](0)
It is still a great challenge to mimic the structure and function of natural rubber by introducing polar components into synthetic polyisoprene. In order to explore the function of phosphate groups on the mechanical properties of polyisoprene rubber, a terminally functionalized compound (PIP-P) containing phosphate groups was synthesized and further vulcanized to prepare the model compound V-PIP-P. Through analyzing the test results, it was found that these phosphate groups formed polar aggregates in non-polar polyisoprene rubber matrix, serving as an additional dynamic cross-linking sites, which increases the cross-linking density and improves mechanical properties. The influence of the phosphate groups on the strain-induced crystallization (SIC) was further investigated via synchrotron wide-angle X-ray diffraction (WAXD) experiment. These phosphate group aggregates not only reduced the onset strain of SIC, but also slowed down the molecular chain mobility, which hinder the crystal lateral growth. The above results help us to gain a deeper understanding for the function of phosphate groups in the formation of “naturally occurring network” and guide the molecular design of next generation polyisoprene rubber.
Coalescence Suppression in Flowing Polymer Blends Using Silica Rods with Different Surface Chemistries
Si-Ying Xiang, Li-Sa-Ya Ye, Ya-Jiang Huang, Ya-Dong Lv, Mi-Qiu Kong, Guang-Xian Li
2021, 39(4): 474 -483.   doi: 10.1007/s10118-021-2526-y
[Abstract](286) [FullText HTML](151) [PDF 797KB](0)
Silica rods with homogeneous (hydrophilic or hydrophobic) and amphiphilic surface properties were synthesized and their efficiencies in suppressing the flow-induced droplet coalescence of immiscible polyisobutylene (PIB)/polydimethylsiloxane (PDMS) blends were evaluated via in situ visualization technique. The flow-induced coalescence behavior of blends was found to strongly depend on the surface nature and concentration of silica rods added as well as the blend ratio. While a trace amount of rods promoted coalescence, all kinds of rods demonstrated a morphology refinement effect at high rod concentrations. Good compatibilization effects were obtained at high rod concentrations, especially for hydrophilic and amphiphilic rods. Based on confocal laser scanning microscopy results, these phenomena observed were interpreted reasonably in terms of the selective distribution and aggregation of silica rods, which were suggested to be decisive for the stabilization mechanism and efficiency of these rods.
Temperature-dependent Crystallization and Phase Transition of Poly(L-lactic acid)/CO2 Complex Crystals
Ying Zheng, Cai-Liang Zhang, Yong-Zhong Bao, Guo-Rong Shan, Peng-Ju Pan
2021, 39(4): 484 -492.   doi: 10.1007/s10118-021-2502-6
[Abstract](505) [FullText HTML](192) [PDF 727KB](0)
Semicrystalline polymers can crystallize in the unique crystalline polymorph and show different phase behaviors under the high-pressure CO2 treatment. Understanding such unique crystallization and phase transition behavior is of fundamental importance for the CO2-assisited processing of semicrystalline polymers. Herein, we investigated the polymorphic crystalline structure, phase transition, and structure-property relationships of poly(L-lactic acid) (PLLA) treated by CO2 at different pressures (1−13 MPa) and crystallization temperatures (Tc’s, 10−110 °C). PLLA crystallized in the PLLA/CO2 complex crystals under 7−13 MPa CO2 at Tc≤50 °C but the common α crystals under the high-pressure CO2 at Tc≥70 °C. Solid-state nuclear magnetic resonance analysis indicated that the PLLA/CO2 complex crystals possessed weaker interactions between the PLLA chains than the common α crystals. The PLLA/CO2 complex crystals were metastable and transformed into the thermally stable α crystals via the solid-to-solid route during heating or annealing at the temperature above 50 °C. The complex crystals of PLLA produced at low Tc was more ductile than the α crystals due to the lower crystallinity and the plasticizing effect of CO2.
Unusual Spherulitic Morphology of Poly(propylene fumarate)
Xiao-Yu Meng, Yi Li, Shu-Fang Yao, Xue-Wei Wei, Hai-Mu Ye
2021, 39(4): 493 -500.   doi: 10.1007/s10118-021-2518-y
[Abstract](329) [FullText HTML](157) [PDF 818KB](4)
Spherulites are the most common crystalline morphology and thus the visual expression of crystal structures for polymers. The diversified patterns have provided intuitive morphology probes for various crystallization behaviors, while the correlations between them are still needed to be enriched. In this work, the complicated spherulitic morphology of poly(propylene fumarate) (PPF), which is sensitive to crystallization temperature, is investigated. PPF melt, respectively, crystallizes into rough spherulites, regularly banded spherulites, and spherulites containing both two kinds of morphology at low, high, and mediate temperatures. By systematically assaying, it is clear that the growth axis along the radial direction changes from a-axis to b-axis as the crystallization temperature increases, which leads to the formation of unique crystallization-temperature-dependent spherulites. Based on detailed characterization of Fourier transform infrared spectroscopy, the packing state of the specific hydrogen bonds of “C=C―H···O=C―C=C” in PPF crystal lattices is determined, and furthermore, the mechanism for temperature-dependent selection of growth axes for PPF spherulites in melt is reasonably speculated.
Effect of Interfacial Adsorption on the Stability of Thin Polymer Films in a Solvent-induced Process
Lin Xu, Tong-Fei Shi, Li-Jia An, Yu-Yuan Lu, Li-Na Wang
2021, 39(4): 501 -511.   doi: 10.1007/s10118-020-2493-8
[Abstract](395) [FullText HTML](182) [PDF 860KB](0)
The stability of ultrathin polymer films plays a crucial role in their technological applications. Here, we systematically investigated the influence of interfacial adsorption in physical aging and the stability of thin polymer films in the solvent-induced process. We further identify the stability mechanism from the theory of thin film stability. Our results show that the aging temperature and film thickness can strongly influence the stability of thin PS films in acetone vapor. Physical aging can greatly improve the stability of thin polymer films when the aging temperature Taging1>Tg. A thinner PS film more quickly reaches a stable state via physical aging. At short aging time, the formation of the adsorbed layer can reduce the polar interaction; however, it slightly influences the stability of thin polymer films in the solvent-induced process. At later aging stage, the conformational rearrangement of the polymer chains induced by the interfacial effect at the aging temperature Taging1 plays an important role in stabilizing the thin polymer films. However, at Taging2<Tg, the process of physical aging slightly influences the stability of the thin polymer films. The formation of the adsorbed layer at Taging2 can reduce the short-range polar interaction of the thin film system and cannot suppress the instability of thin polymer films in the solvent-induced process. These results provide further insight into the stable mechanism of thin polymer films in the solvent-induced process.
Combined Molecular Dynamics Simulation and Rouse Model Analysis of Static and Dynamic Properties of Unentangled Polymer Melts with Different Chain Architectures
Pu Yao, Lu-Kun Feng, Hong-Xia Guo
2021, 39(4): 512 -524.   doi: 10.1007/s10118-020-2489-4
[Abstract](505) [FullText HTML](208) [PDF 809KB](0)
Chain architecture effect on static and dynamic properties of unentangled polymers is explored by molecular dynamics simulation and Rouse mode analysis based on graph theory. For open chains, although they generally obey ideal scaling in chain dimensions, local structure exhibits nonideal behavior due to the incomplete excluded volume (EV) screening, the reduced mean square internal distance (MSID) can be well described by Wittmer’ theory for linear chains and the resulting chain swelling is architecture dependent, i.e., the more branches a bit stronger swelling. For rings, unlike open chains they are compact in term of global sizes. Due to EV effect and nonconcatenated constraints their local structure exhibits a quite different non-Gaussian behavior from open chains, i.e., reduced MSID curves do not collapse to a single master curve and fail to converge to a chain-length-independent constant, which makes the direct application of Wittmer’s theory to rings quite questionable. Deviation from ideality is further evidenced by limited applicability of Rouse prediction to mode amplitude and relaxation time at high modes as well as the non-constant and mode-dependent scaled Rouse mode amplitudes, while the latter is architecture-dependent and even molecular weight dependent for rings. The chain relaxation time is architecture-dependent, but the same scaling dependence on chain dimensions does hold for all studied architectures. Despite mode orthogonality at static state, the role of cross-correlation in orientation relaxation increases with time and the time-dependent coupling parameter rises faster for rings than open chains even at short time scales it is lower for rings.