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semi-crystalline photovoltaic polymers with siloxane-terminated hybrid side-chains

Science China Chemistry 2017年第4期60卷 528-536页

作者： Yuxiang Li Seyeong Song Song Yi Park Jin Young Kim Han Young WOO Department of Cogno-Mechatronics Engineering Pusan National University Miryang 627-706 Republic of Korea Department of Energy and Chemical Engineering Ulsan National Institute of Science and Technology Ulsan 689-798 Republic of Korea Department of Chemistry Korea University Seoul 136-713 Republic of Korea

Three types of semi-cry stalline photovoltaic polymers were synthesized by incorporating a siloxane-terminated organic/inorganic hybrid side-chain and changing the number of fluorine substituents.A branch point away from a polymer main backbone in the siloxane-containing side-chains and the intra-and/or interchain noncovalent coulombic interactions enhance a chain planarity and facile interchain *** resulting polymers formed strongly agglomerated films with high roughness,suggesting strong intermolecular *** optical band gap of ca.1.7 eV was measured for all polymers with a pronounced shoulder peak due to tight π-π *** increasing the fluorine substituents,the frontier energy levels decreased and preferential face-on orientation was *** siloxane-terminated side-chains and fluorine substitution promoted the intermolecular packing,showing well resolved lamellar scatterings up to(300) for this series of polymers in the grazing incidence wide angle X-ray scattering *** PPsiDTBT,PPsiDTFBT and PPsiDT2 FBT devices showed a power conversion efficiency of 3.16%,4.40%and 5.65%,respectively,by blending with PC_(71)***-type bimolecular charge recombination was similar for three polymeric solar *** main loss in the photocurrent generation for PPsiDTBT:PC_(71)BM was interpreted to originate from the trap assisted charge recombination by measuring light-intensity dependent short-circuit current density(J_(SC)) and open-circuit voltage(V_(Oc)).Our results provide a new insight into the rational selection of solubilizing substituents for optimizing crystalline interchain packing with appropriate miscibility with PC71 BM for further optimizing polymer solar cells.

关键词： siloxane side-chain fluorine substitution semi-crystalline charge transport

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Structural optimization and performance trade-off strategies for semi-crystalline sulfonated poly(arylene ether ketone) membranes in high-concentration direct methanol fuel cells

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Journal of Energy Chemistry 2023年第10期85卷 67-75,I0004页

作者： Di Liu Yunji Xie Zhe Zhao Jinbao Li Jinhui Pang Zhenhua Jiang National&Local Joint Engineering Laboratory for Synthesis Technology of High Performance Polymer Jilin UniversityChangchun 130012JilinChina School of Chemistry and Life Science Changchun University of TechnologyChangchun 130012JilinChina

Direct methanol fuel cells(DMFCs) have attracted extensive attention as promising next-generation energy conversion devices. However, commercialized proton exchange membranes(PEMs) hardly fulfill the demand of methanol tolerance for DMFCs employing high-concentration methanol ***, we report a series of semi-crystalline poly(arylene ether ketone) PEMs with ultra-densely sulfonic-acid-functionalized pendants linked by flexible alkyl chains, namely, SL-SPEK-x(where x represents the molar ratio of the novel monomer containing multiple phenyl side chain to the bisfluoride monomers). The delicate structural design rendered SL-SPEK-x membranes with high crystallinity and well-defined nanoscale phase separation between hydrophilic and hydrophobic phases. The reinforcement from poly(ether ketone) crystals enabled membranes with inhibited dimensional variation and methanol penetration. Furthermore, microphase separation significantly enhanced proton conductivity. The SL-SPEK-12.5 membrane achieved the optimum trade-off between proton conductivity(0.182 S cm^(-1), 80 ℃), water swelling(13.6%, 80 ℃), and methanol permeability(1.6 × 10^(-7)cm~2 s^(-1)). The DMFC assembled by the SL-SPEK-12.5 membrane operated smoothly with a 10 M methanol solution, outputting a maximum power density of 158.3 mW cm^(-2), nearly twice that of Nafion 117(94.2 mW cm^(-2)). Overall, the novel structural optimization strategy provides the possibility of PEMs surviving in high-concentration methanol solutions, thus facilitating the miniaturization and portability of DMFC devices.

关键词： semi-crystalline Ultra-densely sulfonated Flexible alkyl spacer Microscopic morphology High-concentration direct methanol fuel cell

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Durable semi-crystalline interphase engineering to stabilize high voltage Ni-rich cathode in dilute ether electrolyte

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Journal of Energy Chemistry 2023年第4期79卷 110-117页

作者： Zhuangzhuang Cui Shunqiang Chen Qingshun Nian Yecheng Li Yawei Chen Bing-Qing Xiong Zihong Wang Zixu He Shuhong Jiao Xiaodi Ren School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026AnhuiChina

Ethers are promising electrolyte solvents for secondary Li metal batteries because of their excellent reduction ***,their oxidation stability has been mostly relying on the high concentration approach,and limited progress has been made on building effective interphase to protect the cathode from the corrosion of the *** this work,we construct a semi-crystalline interfacial layer on the surface of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)cathode that can achieve improved electrochemical stability in the highly corrosive chemical environment formed by the decomposition of ether *** from traditional brittle crystalline interphases,the optimized semi-crystalline layer with low modulus and high ionic conductivity can effectively relieve electrode strain and maintain the integrity of the interface *** to this design,the continuous oxidation decomposition of ether-based electrolytes could be significantly suppressed and the battery shows outstanding cycling stability(84%capacity retention after 300 cycles).This article provides a solution to address the oxidation instability issue of ether-based electrolytes.

关键词： Cathode/electrolyte interphase semi-crystalline Ether electrolyte High-voltage cathode Li-metal batteries

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Self-recoverable semi-crystalline hydrogels with thermomechanics and shape memory performance

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Science China Materials 2019年第4期62卷 586-596页

作者： Kangjun Zhang Ziguang Zhao Jin Huang Tianyi Zhao Ruochen Fang Mingjie Liu Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education School of Chemistry Beihang University Beijing Advanced Innovation Center for Biomedical Engineering Beihang University International Research Institute for Multidisciplinary Science Beihang University

Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be efficiently utilized in many applications. However, these thermoresponsive hydrogels mostly cannot recover their mechanical states under large strain during the process. Herein, we utilize the heterogeneous comb-type polymer network with semicrystalline hydrophobic side chains to design self-recovery semi-crystalline hydrogels. Based on hydrophilic/hydrophobic cooperative complementary interaction and heterogeneous polymer network, hydrogels can be endowed with excellent thermosensitive properties and mechanical performance. The hydrogels exhibit high compressive strength(7.57 MPa) and compressive modulus(1.76 MPa) due to the semi-crystalline domains formed by association of the hydrophobic poly(ε-caprolactone) PCL. The melting-crystalline transition of PCL and elastic polymer network provide the hydrogels excellent thermomechanical performance and self-recovery property. Furthermore, the hydrogels exhibit shape memory behavior, which can be realized by simple process and smart surface patterning. With these excellent properties, our hydrogels can be applied in sensors, flexible devices and scaffolds for tissue engineering.

关键词： semi-crystalline hydrogels thermomechanics self-recovery shape memory property

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Fabrication and Characterization of semi-crystalline and Amorphous Dielectric Polymer Films for Energy Storage

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Materials Sciences and Applications 2022年第11期13卷 559-568页

作者： Hakeem Ayornu Sohail Anwar Yash Thakur Department of Engineering Penn State Altoona Altoona USA Department of Electrical Engineering and Materials Research Institute The Pennsylvania State University University Park USA

Dielectric polymer films are energy storage materials that are used in pulse power operations, power electronics and sustainable energy applications. This paper reviews energy storage devices with focus on dielectric film capacitors. Two prominent examples of polymer dielectrics Polyetherimide (PEI) and Poly (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) (THV) have been discussed. Polyetherimide (PEI) is an amorphous polymer recognized for its high-temperature capability, low dielectric loss and high dielectric strength. THV is a semi-crystalline polymer with high dielectric constant, high-temperature capability and charge-discharge efficiency. The primary focus of this paper is to introduce the reader to the fabrication procedures and characterization techniques used in research labs for processing of dielectric polymers. The fabrication and characterization process of both polymers has been discussed in detail to shed the light on experimental process in this area of research.

关键词： Dielectric Polymer Film Capacitor Amorphous semi-crystalline Solution-Cast Melt Extrusion

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Fundamental Mechanism of Slow Crack Growth in semi-crystalline Polymers under a Constant Load

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Materials Sciences and Applications 2019年第11期10卷 721-731页

作者： Norman Brown Department of Material Science University of Pennsylvania Philadelphia USA

The purpose is to quantitatively present in a single equation all the factors that affect the failure time by Slow Crack Growth (SCG) in a semi-crystalline polymer (SCP) under a constant load. The fundamental mechanism of fracture is displayed at the molecular level. The rate of fracturing is determined by the Eyring theory of thermal activation. The resulting equation includes the important molecular properties of therein, the length and density of the tie molecules. The underlying microfracture process is the unfolding of the chains in the crystal under the action of the tie molecules.

关键词： Failure semi-crystalline Polymer

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Dynamic Fracture of a semi-crystalline Bio-Based Polymer Pipe: Effect of Temperature

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Journal of Minerals and Materials Characterization and Engineering 2021年第3期9卷 227-244页

作者： Jean Benoit Kopp Jeremie Girardot Arts et Metiers Institute of Technology Université de Bordeaux CNRS INRA INP I2M HESAM Université Talence France

The influence of temperature on the resistance to rapid crack propagation of a semi-crystalline bio-based polymer was studied. The experimental results described in this study allow to initiate a first discussion on the role of viscosity and its link with the fracture behaviour and a heterogeneous microstructure such as the semi-crysalline polymer. Dynamic fracture tests on pipes were carried out. It would appear that a temperature decrease of approximately 40℃ relative to ambient has no significant influence on the average crack propagation velocity (≈0.6cR), fracture energy and surface roughness. On the contrary, crack propagation paths seem to vary with temperature. The difference in fracture behaviour between the amorphous and crystalline phase varies significantly as a function of temperature. The difference between the initiation resistance and the rapid propagation also varies. This difference seems to be significantly reduced by lowering the temperature. The mechanisms of cavitation damage and plastic flow are increasingly limited by the decrease in temperature (and therefore in macromolecular mobility). Crack propagation in the pipe is more extensive and therefore more critical. This is emphasised in particular by the probability of the material to be macro-branched as the temperature decreases.

关键词： Dynamic Fracture Rapid Crack Propagation semi-crystalline Pipe Fractography

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Controlling and Evaluating the Structure and Morphology of Polymers on Multiple Scales

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Journal of Materials Science and Chemical Engineering 2015年第12期3卷 48-60页

作者： Geoffrey R. Mitchell Ana Tojeira Thomas Gkourmpis James J. Holt Peter Harris Marilena Pezzuto Centre for Rapid and Sustainable Product Development Institute Polytechnic of Leiria Marinha Grande Portugal Innovation & Technology Borealis AB Stenungsund Sweden Department of Physics University of Reading Whiteknghts Reading UK Centre for Advanced Microscopy University of Reading Whiteknights Reading UK CNR-Istituto di Chimica e Tecnologia dei Polimeri Pozzuoli Italy

crystalline polymers spontaneously form hierarchical structures although the precise manner in which these scales of structure are interconnected especially terms of the formation and evolution of the complete structure remains unclear. We have set out to control these scales of structure by introducing additional components which self-assemble in to nano-scale units which then direct the crystallisation of the polymer matrix. In other words, we first assemble a low concentration top-level structure which is designed to template or direct the sub-sequent crystallisation of the matrix polymer. This top level structure takes on the role of controlling the structure. We have set out to both establish the design principles of such structures and to develop experimental procedures which allow us to follow the formation of such complex hierarchical polymer structures. In particular we focus of the relationships between these different levels of structure and time sequence of events required for the structure to evolve in the targeted manner. In this programme, we have exploited time-resolving small-angle X-ray scattering and electron microscopy together with neutron scattering to probe and quantify the different scales of structure and their evolution. We highlight new neutron scattering instrumentation which we believe have great potential in the growing field of hierarchical structures in polymers. The addition of small quantities of nanoparticles to conventional and sustainable thermoplastics leads to property enhancements with considerable potential in a number of areas Most engineered nano-particles are highly stable and these exist as nano-particles prior to compounding with the polymer resin, they remain as nano- particles during the active use as well as in the subsequent waste and recycling streams. In this work we also explore the potential for constructing nano-particles within the polymer matrix during processing from organic compounds selected to provide nano

关键词： Component semi-crystalline Polymers Morphology Texture Nucleation Growth Shear Flow

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