- Abstract：The synthesis of functionalized rubber copolymers is a topic of great research interest. In this study, we present a novel approach for the direct construction of α-functionalized 3,4-polyisoprene through polymerization of polar monomers and isoprene monomer. The α-functionalized 3,4-polyisoprene was successfully synthesized via in situ sequential polymerization using the iron-based catalytic system (Fe(acac)3/IITP/AliBu3), exhibiting high activity and resistance to polar monomers without requiring protection of polar groups. The structure of α-functionalized 3,4-polyisoprene was confirmed by proton nuclear magnetic resonance spectroscopy (1H-NMR) and two-dimensional diffusion-ordered spectroscopy (2D DOSY) spectra analysis. The introduction of polar groups, particularly hydroxyl groups, enhanced the hydrophilicity of the copolymer. This was evidenced by a decrease in the water contact angle from 106.9° to 96.4° with increasing hydroxyl content in the copolymer.Keywords：Iron-based catalyst;3,4-Polyisoprene;α-Functionalized;In situ sequential polymerization;Hydrophilicity5|0|0
Updated：2025-06-30 - Abstract：The slow phase transition from form II to form I has always been an important factor that restricts the processing and application of polybutene-1 (PB-1). After extensive efforts, a set of effective methods for promoting the phase transition rate in PB-1 was established by adjusting the crystallization, nucleation, and growth temperatures. Nevertheless, low-molecular-weight PB-1 (LMWPB-1) faces challenges because this method requires a low crystallization temperature, which is difficult to achieve during extrusion processing. In this study, we attempted to increase the phase transition rate in PB-1 by changing the annealing temperature after processing rather than the crystallization temperature in the classical scheme. The results indicated that regardless of low- or high-molecular-weight PB-1, repeated annealing between 0 and 90 oC could also promote form II to form I phase transition. The initial content of form I increased with the heating and cooling cycles. The half-time of the phase transition (t1/2) was also shortened after heating/cooling. After 100 heating/cooling cycles, t1/2 was reduced to one-quarter of that without annealing, which had almost the same effect as the crystallization temperature at 25 °C in promoting the phase transition. This study indicates that annealing after processing is also an important factor affecting the phase transition of PB-1, and should receive sufficient attention.Keywords：Polybutene-1;Phase transition;Alternative annealing;Extrusion processing19|9|0Updated：2025-06-26
- Abstract：Thermoresponsive hydrogels based on poly(N-isopropylacrylamide) (PNIPAm) often undergo syneresis upon heating, and thus become irrecoverable in shape. To overcome this limitation, we copolymerize tetra-armed PNIPAm precursor with tetra-armed poly(ethylene glycol) (PEG) precursor. After incorporating the hydrophilic PEG components, the hydrogel samples exhibited recoverable swellability during repeated heating-cooling cycles, during which phase segregation occurred, and the water repelled from the PNIPAm-rich phase can be accommodated in the PEG-rich phase. As a result, recoverability relied on the swellability of the PEG-rich phase, which correlated quantitatively with the molar mass and concentration of the precursor solution. This study provides an effective protocol for the molecular design of stimuli-responsive hydrogels with a desired degree of shape recoverability.Keywords：Polymer gel;Thermodynamics;Swellability;Phase separation;Chain conformation39|6|0Updated：2025-06-23
- Abstract：Highly oriented poly(vinylidene fluoride) (PVDF) ultrathin films with different β-phase contents were prepared using the melt-draw method. The effect of β-phase content on α-β phase transition of highly oriented PVDF ultrathin films induced by stretching was investigated using transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The results show that stretching can enhance the crystallinity and increase the average thickness of the lamellae. A full α-β phase transition can be achieved for PVDF ultrathin films of 20.6% β phase stretched to a λ (stretching ratio) of 1.5, while few α phases still exist for ultrathin films of 35.0% β phase, together with bent and tilted lamellae. Compared to thicker PVDF films undergoing stretching-induced α-β phase transition, the higher α-β phase transition efficiency of the PVDF ultrathin films can be attributed to the parallel aligned lamellar structure. Moreover, a higher β-phase content can suppress α-β phase transition because of the stress concentration effect of β-phase. Ultimately, these results provide valuable insights into the stretching-induced α-β phase transition of PVDF ultrathin films.Keywords：Poly(vinylidene fluoride);Stretching;α-β phase transition;β-phase content35|5|0Updated：2025-06-20
- Abstract：The design of low-cost and high-performance cyclic olefin copolymers remains challenging. Ethylene copolymers with dicyclopentadiene (DCPD) were prepared using Ph2C(Cp)(Flu)ZrCl2 (Cat. 1), rac-Et(Ind)2ZrCl2 (Cat. 2), Me2C(Cp)(Flu)ZrCl2 (Cat. 3) and Me2Si(Ind)2ZrCl2 (Cat. 4) combined with [Ph3C][B(C6F5)4]/iBu3Al. Ni(acac)2/iBu3Al was then used to catalyze the hydrogenation of the intracyclic double bonds of ethylene/DCPD copolymers. The results showed that compared to C2 symmetric catalysts (Cat. 2 and Cat. 4), Cs symmetric catalysts (Cat. 1 and Cat. 3) facilitated the incorporation of copolymers with higher DCPD. 1H- and 13C-NMR spectra indicated that ethylene/DCPD copolymerization occurred via enhancement of the norbornene ring. Additionally, measurement of the reactivity ratios provided further confirmation that the copolymers had random sequence distributions. All these samples demonstrated transmittance values above 90% in the visible wavelength range from 400 nm to 800 nm. By changing the fraction of monomers, the glass transition temperature, refractive index, Young's modulus, and tensile strength of the copolymer increased as the incorporation of DCPD increased, whereas the Abbe number and elongation at break decreased. Compared with ethylene/norbornene and ethylene/tetracyclicdodecene copolymers, ethylene/DCPD copolymers, with excellent optical and mechanical properties, are promising materials.Keywords：Cyclic olefin copolymers;Coordination polymerization;Metallocene catalyst42|15|0Updated：2025-06-16
- Abstract：Consisting of natural histidine residues, polyhistidine (PHis) simulates functional proteins. Traditional approaches towards PHis require the protection of imidazole groups before monomer synthesis and polymerization to prevent degradation and side reactions. In the contribution, histidine N-thiocarboxyanhydride (His-NTA) is directly synthesized in aqueous solution without protection. With the self-catalysis of the imidazole side group, the ring-closing reaction to form His-NTA does not require any activating reagent (e.g., phosphorus tribromide), which is elucidated by density functional theory (DFT) calculations. His-NTA directly polymerizes into PHis bearing unprotected imidazole groups with designable molecular weights (4.2−7.7 kg/mol) and low dispersities (1.10−1.19). Kinetic experiments and Monte Carlo simulations reveal the elementary reactions and the relationship between the conversion of His-NTA and time during polymerization. Block copolymerization of His-NTA with sarcosine N-thiocarboxyanhydride (Sar-NTA) demonstrate versatile construction of functional polypept(o)ides. The triblock copoly(amino acid) PHis-b-PSar-b-PHis is capable to reversibly coordinate with transition metal ions (Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) to form pH-sensitive hydrogels.Keywords：N-thiocarboxyanhydride;Polyhistidine;Controlled ring-opening polymerization;Polypeptide;Poly(amino acid)s36|4|0Updated：2025-06-16
- Abstract：Poly(L-lactide) (PLLA), a leading biodegradable polyester, has demonstrated potential as a sustainable alternative, owing to its excellent biodegradability and rigidity. However, their slow crystallization kinetics and poor heat resistance limit their application scope. Recent advances have highlighted that the combination of extensional flow and thermal fields can achieve toughness–stiffness balance, high transparency, and good heat resistance. However, the effect of extensional flow on the post-non-isothermal crystallization of PLLA during heating and the resulting crystalline texture remains unclear. In this study, PLLA with a heterogeneous amorphous structure and oriented polymorph was prepared by extensional flow. The effect of heterogeneous amorphous structures on non-isothermal crystallization kinetics during the heating process was studied by thermal analysis, polarized optical microscopy, infrared spectroscopy, and ex situ/in situ X-ray characterization. These results clearly illustrate that extensional flow enhances the formation of oriented crystalline structures, accelerates non-isothermal crystallization, and modulates the polymorphic composition of PLLA. Moreover, an unexpected dual cold-crystallization behavior is identified in ordered PLLA samples upon extensional flow, which is from the extensional flow-induced heterogeneous amorphous phase into α' phase (low-temperature peak) and the pristine amorphous phase into α phase (high-temperature peak). The extensional flow primarily promotes the formation of the more perfect α and α' phases, but has a negative effect on the final content of α phase formed after cold crystallization and α'-to-α phase transformation. The findings of this work advance the understanding of PLLA non-isothermal crystallization after extensional flow and offer valuable guidance for high-performance PLLA upon heat treatment in practical processing.Keywords：Poly(L-lactide);Extensional flow;Heterogeneous amorphous structure;Dual cold crystallization31|8|0Updated：2025-06-09
- Abstract：The dynamics of the drying process of polymer solutions are important for the development of coatings and films. In the present work, digital holographic microscopy (DHM) was performed to capture the drying dynamics of poly(ethylene oxide) (PEO) droplets using a gold nanoparticle tracer, where the heterogeneous flow field in different regions was illustrated. This demonstrates that the gold nanoparticles at either the center or the edge regions of the droplet exhibit anisotropic kinematic behavior. At early stage, Marangoni backflow causes gold nanoparticles to move towards the edge firstly, and the circles back towards the droplet center after arriving the contact line with a sudden increase in z axis for 10.4 μm, indicating the scale of the upward-moving microscopic flow vortices. This phenomenon does not occur in water droplets in the absence of polymers. The gold nanoparticles underwent Brownian-like motion at the center of the PEO droplet or water droplet owing to the low perturbation of the flow field. At the late stage of pinning of the PEO droplets, the motion showed multiple reverses in the direction of the gold nanoparticles, indicating the complexity of the flow field. This study enhances the understanding of the drying dynamics of polymer solution droplets and offers valuable insights into the fabrication of surface materials.Keywords：Polymer solution;Poly(ethylene oxide)32|4|0Updated：2025-06-05
- Abstract：Snow and freezing disasters are recurrent weather and climate phenomena that affect the world annually. These events exert a significant influence on numerous aspects of life, including transportation, power supply, and daily activities, and result in considerable economic losses. This study aims to provide a comprehensive analysis of the regions affected by these disasters, the preventive and responsive measures employed, recent advancements in key materials, and the challenges encountered. By doing so, we can gain a deeper understanding of the vital role, significant advantages, and untapped potential of key materials for effectively preventing and responding to snow and freezing disasters. Furthermore, promoting research and utilization of these materials not only contributes to the development of the safety and emergency equipment industry but also strengthens the supply of advanced and suitable safety and emergency equipment.Keywords：Low-temperature disasters;Snow and freezing disasters;Anti-icing materials;De-icing materials46|17|0Updated：2025-06-03
- Abstract：The ring-opening alternating copolymerization (ROAC) of 3,4-dihydrocoumarin (DHC)/epoxides has been successfully developed using an imidazolium salt of 1-ethyl-3-methylimidazolium chloride (EMIMCl) as a catalyst. The resulting copolymer has a molecular weight of 13.7 kg·mol–1, a narrow molecular weight distribution of 1.03 and a strictly alternating structure. The MALDI-TOF MS characterization and DFT calculations including electrostatic potential (ESP), hydrogen-atom abstraction (HAA), independent gradient model based on hirshfeld partition (IGMH) and atoms-in-molecules (AIM) analysis were used to investigate the metal-free catalytic process. The synergistic effect of anions and cations of EMIMCl for ROAC of DHC and epoxides was demonstrated. This study provides a metal-free catalytic system for the facile synthesis of alternating polyesters from DHC.Keywords：Epoxides80|24|0Updated：2025-05-20
- Abstract：A high humidity-resistant, dual mechanical responsive, and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane (PDMS) substrate with a thin film consisting of 90 wt% poly(vinyl butyral) (PVB) and 10 wt% hydroxypropyl cellulose (HPC) has been reported. The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50% changes in transmittance, which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending. Upon exposure to ethanol vapor or a re-flattening process, wrinkles can be erased, yielding a transparent state. Consequently, the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance. Owing to the insolubility of PVB in water, the wrinkling patterns exhibited excellent durability in high-humidity environments (relative humidity (RH) = 99%). Furthermore, the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system, suggesting potential applications of the designed structure in smart windows, anti-counterfeiting, dynamic display, optical information encryption, and rewritable surfaces.Keywords：Wrinkling surface;Mechanochromism;Optical modulation;High humidity resistance;Patterning73|40|0Updated：2025-04-11
- Abstract：To simultaneously endow thermal conductivity, high glass transition temperature (Tg) and healing capability to glass fiber/epoxy (GFREP) composite, dynamic crosslinked epoxy resin bearing reversible β-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth (GFC@BNNSs). The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated BNNSs. Then, the GFC@BNNSs were impregnated with the mixture of lower concentration (3-glycidyloxypropyl) trimethoxysilane grafted BN micron sheets, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride, which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical performances. The resultant GFREP composite containing less boron nitride particles (17.6 wt%) exhibited superior in-plane (3.29 W m-1 K-1) and through-plane (1.16 W m-1 K-1) thermal conductivities, as well as high Tg of 204 oC (Tg of the unfilled epoxy = 177 oC). The reversible transesterification reaction enabled closure of interlaminar cracks within the composite, achieving decent healing efficiencies estimated by means of tensile strength (71.2%), electrical breakdown strength (83.6%) and thermal conductivity (69.1%). The present work overcame the disadvantages of conventional thermally conductive composites, and provided an efficient approach to prolong the life span of thermally conductive GFREP laminate for high-temperature resistant integrated circuit application.Keywords：Thermally conductive composites;Boron nitride;High-temperature resistance;β-Hydroxyl ester bond;Healing326|36|0Updated：2023-12-04
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Excellent compatibilization effect of a dual reactive compatibilizer on the immiscible MVQ/PP blends
Abstract：Methyl vinyl silicone rubber (MVQ)/polypropylene (PP) thermoplastic vulcanizate (TPV) combines the good melt processability, recyclability and sealing performance as well as biosafety, stain and fluid resistance, and thus it is especially suitable in bio-safety areas and wearable electronic devices, etc. Nevertheless, the compatibility between MVQ and PP phases is poor. A big challenge on the compatibilization of MVQ/PP blends is that neither MVQ nor PP contains any reactive groups. In this study, a dual reactive compatibilizer composed of ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA-co-GMA) and maleic anhydride grafted polypropylene (PP-g-MAH) was designed for the compatibilization of MVQ/PP blends. During melt blending, a copolymer compatibilizer at the MVQ/PP interface can be formed because of the in-situ reaction between EMA-co-GMA and PP-g-MAH. The thermodynamic predict of its compatibilization effect through calculating the spreading coefficient of the in-situ formed copolymer indicates that it can well compatibilize MVQ/PP blends. The experimental results show that under the GMA/MAH molar ratio of 0.5/1, the interface thickness largely increase from 102nm for non-compatibilized blend to 406nm, and the average size of MVQ dispersed phase largely decreases from 2.3μm to 0.36μm, the Tg of the two phases shifts toward each other, the mixing torque and mechanical properties of the blend are increased, all indicating its good compatibilization effect. This study provides a good compatibilizing method for immiscible MVQ/PP blends with no reactive groups in both components for the preparation of high performance MVQ/PP TPVs.Keywords：Methyl vinyl silicone rubber (MVQ), Polypropylene (PP), Immiscible polymer blends, Reactive compatibilization11|1|0Updated：2023-01-04 - Abstract：The active layer of all polymer solar cells (all-PSCs) is composed of a blend of a p-type conjugated polymer (p-CP) as donor and an n-type conjugated polymer (n-CP) as acceptor. All-PSCs possess the advantages of light weight, thin active layer, mechanical flexibility, low cost solution processing and high stability, but the power conversion efficiency (PCE) of the all-PSCs was limited by the poor photovoltaic performance of the n-CP acceptors before 2016. Since the report of the strategy of polymerized small molecule acceptors (PSMAs) in 2017, the photovoltaic performance of the PSMA-based n-CPs improved rapidly, benefitted from the development of the A-DA’D-A type small molecule acceptors (SMAs). PCE of the all-PSCs based on the PSMA acceptors reached 17%~18% recently. In this review article, we will introduce the development history of the n-CPs, especially the recent research progress of the PSMAs. Particularly, the structure-property relationship of the PSMAs is introduced and discussed. Finally, current challenges and prospects of the n-CP acceptors are analyzed and discussed.Keywords：n-type conjugated polymers;All-polymer solar cells;polymer acceptors;polymerized small molecule acceptors.12|1|5Updated：2023-01-04
- Abstract：Since the first report of diketopyrrolopyrrole (DPP)-based conjugated polymers for organic thin-film transistors (OTFTs), these polymers have attracted great attention as representative semiconductors in high-performance OTFTs. Through unremitting efforts in molecular-structure regulation and device optimization, significant mobilities exceeding 10 cm2V–1s–1 have been achieved in OTFTs, greatly promoting the applied development of organic circuits. In this review, we summarize our progress in molecular design, synthesis and solution-processing of DPP-based conjugated polymers for OTFT devices and circuits, focusing on the role of design strategies, synthesis methods and processing techniques. Furthermore, the remaining issues and future outlook in the field are briefly discussed.Keywords：Diketopyrrolopyrrole, Polymer semiconductors, Organic thin-film transistor, Organic circuits26|2|0Updated：2023-01-04
- Abstract：Precisely optimizing the morphology of functional hybrid polymeric systems is crucial to improve its photophysical property and further extend their optoelectronic applications. The physic-chemical property of polymeric matrix in electrospinning (ES) processing is a key factor to dominate the condensed structure of these hybrid microstructures and further improve its functionality. Herein, we set a flexible polyethylene oxide (PEO) as the matrix to obtain a series of polydiarylfluorenes (including PHDPF, PODPF and PNDPF) electrospun hybrid microfibers with a robust deep-blue emission. Significantly different from the rough morphology of their poly(N-vinylcarbazole) (PVK) ES hybrid fibers, polydiarylfluorenes/PEO ES fibers showed a smooth morphology and small size with a diameter of 1~2 μm. And there is a relatively weak phase separation under rapid solvent evaporation during the ES processing, associated with the hydrogen-bonded-assisted network of PEO in ES fibers. These relative “homogeneous” ES fibers present efficient deep-blue emission (PLQY>50%), due to weak interchain aggregation. More interestingly, low fraction of planar (β) conformation appears in the uniform PODPF/PEO ES fibers, induced by the external traction force in ES processing. Meanwhile, PNDPF/PEO ES fibers present a highest sensitivity than those of other ES fibers, associated with the smallest diameter and large surface area. Finally, compared to PODPF/PVK fibers and PODPF/PEO amorphous ES fibers, PODPF/PEO ES fibers obtained from DCE solution exhibit an excellent quenching behavior toward a saturated DNT vapor, mainly due to the synergistic effect of small size, weak separation, β-conformation formation and high deep-blue emission efficiency.Keywords：matrix effect, electrospun fibers, polydiarylfluorenes, planar conformation, explosive detection4|0|0Updated：2023-01-04
- Abstract：The development of donor-acceptor (D-A) type conjugated polymers depends largely on the design of novel A building blocks. Herein, we report a novel A building block based on the cyano-substituted organoboron unit (SBN-3). Compared with the most common fluorine-substituted B←N unit, SBN-3 displays a significantly downshifted LUMO energy level because of the strong electron-withdrawing ability of cyano groups. In addition, due to the greater impact of cyano substitution on LUMO than on HOMO, SBN-3 exhibits a reduced band gap, near-infrared absorption and fluorescence properties. The D-A type conjugated polymers based on the cyano-substituted B←N unit with thiophene-based units show narrow optical band gaps of ca. 1.3 eV as well as distinctive electronic structures, i.e., delocalized LUMOs and localized HOMOs. This work thus provides not only an effective approach to design strong A units but also a new electron-deficient building block for D-A type conjugated polymers.Keywords：cyano-substituted;B←N unit;Building block;narrow band gap;D-A type conjugated polymers4|2|1Updated：2023-01-04
- Abstract：A series of thermoplastic polyimide resins with a low coefficient of thermal expansion (CTE) was prepared by blending a rigid resin system 3,3',4,4'-Biphenyltetracarboxylic dianhydride(BPDA)/p-phenylenediamine(PDA) with a flexible resin system 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic anhydride (BPADA)/PDA. The effects of the blending ratio on the macromolecular coil size, free volume, and CTE of the mixed system were studied. The mixing is carried out in the prepolymer polyamide acid (PAA) stage, which makes the two systems more compatible and is conducive to the formation of a semi-interpenetrating network structure between the rigid molecular chains and flexible molecular chains. The flexible structure of the BPADA/PDA system is used to ensure the melt processing performance. The rigid characteristics of the BPDA/PDA system can inhibit the movement of molecular chains and reduce the free volume fraction, thereby reducing the CTE value. When the rigid system content reaches 30%, the CTE can be reduced to 38 ppm/K. This method provides a new approach for studying low CTE thermoplastic polyimide resins.Keywords：Coefficient of thermal expansion (CTE);Thermoplastic polyimide;Melt processing property;Blending10|1|0Updated：2023-01-04
- Abstract：Molecular doping is one of the most important tools to manipulate the electrical properties of conjugated polymers for application in organic optoelectronics. The polymer crystallinity and distribution position of the dopant crucially determine electrical conductivity of the doped polymer. However, in solution-mixed doping, the interplay between polymer and dopant leads to highly structural disorder of polymer and random arrangement of dopant. Here, we propose a strategy to ensure the dopant induced polarons have high charge dissociation and transport by letting the conjugated polymers aggregate in the marginal solvent solution by cooling it from higher temperature to room temperature. We select poly(3-hexylthiophene-2,5-diyl) (P3HT) solution doped by 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) as a model system. The P3HT crystallizes in the marginal solvent, such as 1,1,2-trichloroethane (TCE) driven by the favor π-π interaction between planar polymer backbone. The dopant F4TCNQ enters the alkyl side chain region not the π-π stacking region and thus guarantees high crystallinity and the π-π interaction of P3HT. This distribution of F4TCNQ which away from the polymer backbone to ensure higher charge dissociation and transport. Finally, we obtained a high conductivity value of 23 S/cm by doping P3HT with 20% F4TCNQ by using the marginal solvent, which is higher than doping P3HT with a disordered coil conformation in chlorobenzene (CB) of 7 S/cm, which the dopants enter both the alkyl side chain region and the π-π stacking region.Keywords：Solvent;Crystalline;Dopant location;Doping efficiency;Electrical conductivity26|4|1Updated：2023-01-04
- Abstract：Simultaneous realization of superior mechanical and antifouling properties is critical for a coating. The use of stereoscopic polysiloxanes in place of linear polysiloxanes to fabricate antifouling coatings can combine properties of organic and inorganic materials, i.e., they can exhibit both high hardness and wear resistance from inorganic components as well as the flexibility and tunability from organic components. This strategy is used to prepare a hard yet flexible antifouling coating or polymer–ceramic hybrid antifouling coatings. In this mini-review, we report the recent advances in this field. Particularly, the effects of stereoscopic polysiloxane structure on their mechanical and antifouling properties are discussed in detail.Keywords：Antifouling coating;Organic-inorganic hybrid;Sol-gel;Hard yet flexible15|3|3Updated：2023-01-04
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