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Challenges and Opportunities of Precision Polymer chemistry

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Chinese Journal of Polymer Science 2022年第10期40卷 1129-1130页

作者： Shiyong Liu CAS key laboratory of soft matter chemistry Department of Polymer Science and EngineeringSchool of Chemistry and Materials ScienceUniversity of Science and Technology of China(USTC)

Since Hermann Staudinger coined the revolutionary concept of macromolecules in 1920, synthetic polymers have served as a major game changer to our society and become indispensable in our daily lives. Unlike biomacromolecules (e.g., DNA and proteins) possessing precise molar masses/chain sequences/topologies and specific biological functions, synthetic polymers are abiotic materials characterized by broad chain length distributions and undefined sequences. To bridge the gap between natural and synthetic polymers, the biomimetic synthesis of polymers with precise chain length, sequences and topologies has been long pursued and yet unmet in polymer science.

关键词： precise sequences synthetic

Embedding pyridine units in acceptors to construct donor-acceptor conjugated polymers

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Chinese Chemical Letters 2019年第1期30卷 25-30页

作者： Zi-Yuan Wang Jie-Yu Wang Jian Pei Beijing National laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Key Laboratory of Polymer Chemistry and Physics of Ministry of Education Center for Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University

The development of donor-acceptor(D-A) conjugated polymers greatly promotes the device performance in organic electronics. Recently, the strategy of embedding pyridine units into D-A conjugated polymer backbones has attracted much attention due to the resulted lowered LUMO levels. In addition, the possible non-bonding interactions resulted from the nitrogen atoms also improve the coplanarity of the polymer backbones. All these factors have great contribution to enhance the device performance. In this review, we summarized the recent development of pyridine-embedded D-A conjugated polymers and their applications in organic field-effect transistors(OFETs).

关键词： Donor-acceptor Conjugated polymers Coplanarity Pyridine-embedded Organic electronics

Nanoscale engineering of conducting polymers for emerging applications in soft electronics

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Nano Research 2021年第9期14卷 3112-3125页

作者： Tao Wang Yiwen Bao Mengdi Zhuang Jiacheng Li Juncheng Chen Hangxun Xu Hefei National laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Soft Matter ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

soft electronics featuring exceptional mechanical compliance and excellent electrical performance hold great promise for applications in soft robotics,artificial intelligence,bio-integrated electronics,and wearable *** stretchable and conductive materials are crucial for soft electronics,enabling large-area and scalable fabrication,high device density,and good mechanical *** polymers are inherently stretchable and *** can be precisely synthesized from vastly available building blocks,and thus they provide a fruitful platform for fabricating soft ***,amorphous bulk-phase conducting polymers typically exhibit poor mechanical and electrical ***,it is highly desirable to develop novel engineering approaches to overcome the intrinsic limitations of conducting *** recent years,numerous engineering strategies have been developed to enhance their performances in soft electronic devices via constructing various *** this review,we first summarize several unique methodologies to fabricate conducting polymer-based *** then discuss how nanoscale engineering approaches can improve several crucial parameters,including electrical conductivity,stretchability,sensitivity,and self-healing property of conducting ***,we also discuss device-level integration of conducting polymer-based nanostructures with other materials for applications in skin-inspired electronics and bio-integrated ***,we provide perspectives on challenges and future directions in engineering nanostructured conducting polymers for soft electronics.

关键词： conducting polymers semiconducting polymers soft electronics nanostructures stretchable electronics

Entanglement on Nucleation Barrier of Polymer Crystal

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Chinese Journal of Polymer Science 2022年第12期40卷 1640-1650,I0009页

作者： Fan Peng Cui Nie Ting-Yu Xu Jun-Fang Sheng Wei Chen Wan-Cheng Yu Liang-Bin Li National Synchrotron Radiation laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Science and Technology of ChinaHefei 230026China

We propose a theoretical approach to quantitatively account for the role of entanglement in the nucleation of polymer melts, which is the unique feature of polymer differentiated from small molecules. By performing molecular dynamics simulations, we obtain the nucleation barriers of polymer systems with different entanglement densities, which exhibits an opposite trend compared to the prediction of the classic nucleation theory(CNT). To amend the deficiency of the CNT in polymer crystallization, we introduce the entanglement free energy to reflect the role of entanglement in polymer nucleation. Specifically, the polymer nucleation not only involves free energies of monomers inside and on the surface of a nucleus as considered in the CNT, but also affects the entanglement network around the nucleus. Our theoretical approach provides a reasonable interpretation for the unsolved nucleation phenomena of polymers in simulations and experiments.

关键词： Nucleation Entanglement Molecular simulation

A newly-designed self-powered electrochromic window

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Science China chemistry 2017年第1期60卷 84-89页

作者： Xingming Wu Jianming Zheng Chunye Xu Hefei National laboratory for Physical Sciences at Microscale CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 China

By converting incident light into electric power,self-powered electrochromic window(SP-ECW)can achieve color change in electrochromic layer with no need for external *** this work,a newly-de signed SP-ECW is proposed for altering its color between deep blue and colorless state according to on/off state of incident *** device consists of a working electrode with planar integration of photovoltaic(PV)and electrochromic(EC)elements on one electrode,a platinum counter electrode and a redox electrolyte comprising Br^-/Br_3^-couple.A high transmittance modulation of 41%at 582 nm is *** energy converted from light is not only sufficient to drive the device,but also can be outputted to the external circuit.

关键词： self-powered electrochromic window redox electrolyte poly(3 4-(2 2-dimethylpropylenedioxy)thiophene) transmittancemodulation light intensity

A Unified Thermodynamic Model of Flow-induced Crystallization of Polymer

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Chinese Journal of Polymer Science 2021年第11期39卷 1489-1495页

作者： Cui Nie Fan Peng Ting-Yu Xu Jun-Fang Sheng Wei Chen Liang-Bin Li National Synchrotron Radiation laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Science and Technology of ChinaHefei 230026China

We propose a unified thermodynamic model of flow-induced crystallization of polymer(uFIC),which incorporates not only the conformational entropy reduction but also the contributions of flow-induced chain orientation,the interaction of ordered segments,and the free energy of crystal nucleus and crystal ***,it clarifies the determining parameters of the critical crystal nucleus size,and is able to account for the acceleration of nucleation,the emergence of precursor,different crystal morphologies and structures induced by *** on the nucleation barrier under flow,we analyze at which condition precursor may occur and how flow affects the competition among different crystal forms such as orthorhombic and hexagonal phases of *** to the uFIC model,the different crystal morphologies and structures in the flow-temperature space have been clarified,which give a good agreement with experiments of FIC.

关键词： Flow-induced crystallization Unified thermodynamic model Flow-induced chain orientation

Chain Flexibility and Connectivity:The Uniqueness of Polymer Crystallization

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Chinese Journal of Polymer Science 2023年第1期41卷 7-13页

作者： Liang-Bin Li National Synchrotron Radiation laboratory CAS Key Laboratory of Soft Matter ChemistryAnhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmUniversity of Science and Technology of ChinaHefei230026China

Theory of polymer crystallization is listed as one of the top ten current challenges in polymer *** the uniqueness of polymer crystallization should be the first step to search for the roadmap for targeting this *** flexibility and connectivity are two peculiar characteristics of polymers,which differentiate their dynamics and structures from that of small *** uniqueness of polymer crystallization must also stem from these two peculiar characteristics,which,however,has not been attracted significant attention.A local structure order may be essential in assisting the transformation of flexible chain to rigid segment with conformational *** entanglement pressure and entanglement free energy may help to understand how entanglement affect nucleation in polymer network and why the interlamellar amorphous layer always accompany the formation of crystal *** recommendations will be given for future study.

关键词： Polymer crystallization Chain flexibility Chain connectivity Nucleation

Structural Evolution of LLDPE-LMW/HMW Blend during Uniaxial Deformation as Revealed by In Situ Synchrotron Radiation X-ray Scattering

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Chinese Journal of Polymer Science 2021年第1期39卷 102-112,I0007页

作者： Pin-Zhang Chen Hao-Yuan Zhao Zhi-Jie Xia Qian-Lei Zhang Dao-Liang Wang Ling-Pu Meng Wei Chen National Synchrotron Radiation laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Science and Technology of ChinaHefei 230029China

The structural evolutions of LLDPE-LMW/HMW blend during uniaxial deformation at temperatures of 80 and 120 ℃ were investigated by the in situ synchrotron radiation small-and wide-angle X-ray scattering(SR-SAXS/WAXS). The magic sandwich echo(MSE) sequence was used to detect a virtually dead-time-free induction decay(FID) for solid-state NMR analysis. The thermal property of the blend was first checked by DSC,and the temperature dependence of the overall crystallinity was obtained by MSE-FID. The onset melting temperature is determined to be 116 ℃(DSC), and the enhanced π-flip motions in the crystalline domains are clearly observed at T>60 ℃ by MSE-FID. For deformation at 80 ℃, the lamellae become staggered in the strain-softening region as shown by the four-point SAXS pattern, whereas further deformation leads to the melting-recrystallization in the strain-hardening region. For deformation at 120 ℃, the six-point SR-SAXS signal appears just after the four-point SR-SAXS signal, which indicates the formation of new lamellae along deformation direction. In addition, no phase transition occurs in the whole deformation process at both temperatures. Current work shows the detailed temperature dependence microstructural evolution of LLDPELMW/HMW blend. This is expected to provide more structural information for correlating microscopic structure with macroscopic mechanical performance.

关键词： Polyethylene In situ SAXS/WAXS NMR Microstructural evolution

Unconventional 2D Periodic Nanopatterns Based on Block Molecules

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Chinese Journal of Polymer Science 2023年第10期41卷 1508-1524页

作者： Bo Hou Wen-Bin Zhang Yu Shao Beijing National laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry&Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

This review summarizes the self-assembly of block molecules forming unconventional two-dimensional(2D)periodic ***,we emphasize the structural evolution from simple columnar phases to complex 2D tiling morphologies in soft materials including block copolymers,liquid crystals,giant molecules,***,the state-of-the-art nanofabrication technologies for making sophisticated nanostructures with specific functions via combining both bottom-up assembly and top-down lithography-based methods are discussed,highlighting the use of directed self-assembly ***,we provide our perspective on this *** further increasing the complexity of block molecules and the designability of lithography,low-dimensional ordered morphologies will be particularly promising for further application in nanotechnology.

关键词： Two-dimensional ordered morphologies Block molecules Directed self-assembly Nanofabrication Tilings and patterns