最新刊期
卷 52 ， 期 6 ， 2021
- 摘要：Two-dimensional polymers (2DPs) are molecular sheets of atomic layer thickness with periodic arrangements in a two-dimensional plane connected by covalent bonds. They have drawn much attention in recent years because of their lightweight, flexibility, adjustable structure, and high adaptability. Graphene is a unique natural 2DP, with a honeycomb lattice connected by sp2 hybridized carbon atoms. Due to its excellent conjugated structure and stability, graphene has huge application potential in energy storage, environment, and biomedicine. However, there is a strong π-π stacking effect between two-dimensional graphene sheets, which leads to its poor dispersion and limits its performance in practical applications. To address the above issues, our group has developed strategies for the preparation of three-dimensional-graphene (3DG) nanocomposites with a series of electrochemically active materials for efficient electrochemical energy storage. What’s more, inspired by graphene, new kinds of 2DP materials have been developed, such as two-dimensional covalent organic framework (2D COF) and two-dimensional covalent triazine framework (2D CTF). We hope to develop facile preparation methods for high-quality 2DPs. Through the effective assembly, combination, and functional modification, large-scale applications of 2DP in the field of electrochemical energy storage and conversion can be realized. The controllable preparation of 2DPs is of great significance to the study of the relationship between the structure and performance of 2DPs. This article first focuses on rapid preparation, assembly, functional composite, and electrochemical applications of the natural two-dimensional graphene. Then, the preparation methods and effective molecular design of 2D COF, silicene, and 2D CTF are summarized. The article provides ideas for the controllable preparation and efficient application of 2DPs with an emphasis on the structure-property relationship of 2DPs.关键词：Two-dimensional polymer;Three-dimensional graphene;Two-dimensional covalent organic framework;Two-dimensional covalent triazine framework;Electrochemical energy storage
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发布时间：2021-11-03 - 摘要：Interfacial polymerization is an important method for preparing functional polymer materials. At present, in both fields of solid-liquid and liquid-liquid interfacial polymerizations, there are suspending problems which need to be solved via computer simulation studies. In the present paper, the research advances, focusing on the simulation study of kinetics of interfacial polymerization, are summarized with an emphasis on the research results from the authors’ group. The discussions are divided into three sections. (1) Recent development of simulation method for the interfacial polymerization. The difficulty for the theoretical and simulation study on investigating this issue lies in the scale inconsistency between the polymer diffusion dynamics and the reaction kinetics of polymerization. The coarse-grained simulation method coupled with the stochastic reaction model, which is developed by the authors’ group, is proved an appropriate strategy for solving this problem and mainly introduced in the paper. (2) Controlling factors in the solid-liquid interfacial polymerization. The surface modification by polymer brushes is a typical solid-liquid interfacial polymerization. The effects of main controlling factors on the growth kinetics of the grafted chains, including the grafting surface curvature, the arrangement of reactive sites and the reacting units, are investigated in-depth, respectively. (3) New advances on the liquid-liquid interfacial polymerization. Focusing on the representative polymerization-induced self-assembly and supramolecular interfacial polymerization systems, we develop the corresponding simulation models and investigate the structures and dynamics. This paper is expected to guide the experimentalists to realize the theory-driven controllable design and preparation of polymer materials.关键词：Solid-liquid interfacial polymerization;Liquid-liquid interfacial polymerization;Coarse-graining;Molecular weight distribution;Polydispersity
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发布时间：2021-11-03 - 摘要：Supramolecular topological polymers not only possess the dynamic and tunable characteristics of non-covalent band, but also have the unique chemical and physical properties of covalent topological polymers. Furthermore, they display fascinating features such as reversibility, adaptiveness, self-healing and stimuli-responsiveness. Hence, supramolecular topological polymers provide new ideas for the creation of new polymer species and functional materials. In this paper, we reviewed the recent and important progress of supramolecular topological polymers from the synthesis, self-assembly to function and application. The synthetic methodologies of hyperbranched, dendritic, star, brush, crosslinking and cyclic supramolecular polymers including the direct and indirect strategies, were first emphasized. The controlled self-assembly behaviors of supramolecular topological polymers were then summarized from two aspects including the internal structure parameters (such as hydrophilic-hydrophobic ratio, topological structure, non-covalent bond types and force strengths) and external stimuli-responsiveness (such as thermal, pH, light, redox, ion, and enzyme). As a result, the above supramolecular topological polymers can easily self-assemble to form hierarchical supramolecular structures with multiple stimuli-responsiveness at different scales and dimensions, such as spherical/cylindrical micelles, vesicles, and fibers/helical tubes. On the other hand, supramolecular topological polymers can achieve specific functional properties by the introduction of functional molecules, such as chromophore groups and biological targeted molecules. Next, the potential applications of supramolecular topological polymers in the fields of biomedical, photoelectric and self-healing materials were comprehensively discussed. Finally, the key scientific issues and possible challenges in the field of supramolecular topological polymers were briefly summarized.关键词：Supramolecular polymer;Topological polymer;Supramolecular hyperbranched polymer;Controlled self-assembly;Functional assemblies
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发布时间：2021-11-03 - 摘要：Molecular-scale electronics is a cutting edge research field aimed at achieving electronic functions by utilizing single molecules and their monolayer assemblies as active components. Molecular devices based on self-assembled monolayers (SAMs) show high potential towards the application of molecular electronics in the future. However, the development of functional SAM devices is still in its infancy, and their performance is far from meeting the requirements of practical applications. In this review, we first summarize the methods for fabricating SAM devices using soft top-contact electrodes, including liquid metals (mercury and Ga/In eutectic), conductive polymers (e.g., PEDOT: PSS) and graphene, and graphene has been considered as an ideal choice for building SAM devices because of it high electrical conductivity, mechanical flexibility, chemical stability, optical transparency and processability. Then we introduce recent progress on functional SAM devices, especially solid-state photoswitchable devices, and we highlight that rational molecular design (anchor, linker, and functional group) is crucial for improving the device performance. For example, molecular engineering strategies overcoming intermolecular steric hindrance can boost the photoisomerization ability of azobenzenes in SAMs and thus the photo-responsibility of their photoswitchable devices. We also provide an overview on how to fabricate conjugated polymers based SAM devices and discuss their charge transport behaviors in two kinds of junctions, i.e., vertical and planar junctions. These results indicate that conjugated polymerss are distinct from small molecular materials and may hold advantages in optoelectronic functions. For example, properly designed conjugated polymers can mediate long-range charge transport and thus act as molecular wires. Moreover, functional SAM devices based on conjugated polymers can outperform the small molecular counterpart on key device performance, such as on-off ratios for optoelectronic switches. Finally, a perspective on future research directions and challenges in this field is presented.关键词：Molecular electronics;Self-assembled monolayers;Molecular device;Conjugated polymer
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发布时间：2021-11-03 - 摘要：This review introduces the discovery of inorganic ionic oligomers and their controllable polymerization and crosslinking for materials preparation. It is well recognized that classical nucleation and crystal growth commonly lead to the formation of inorganic particles, rather than continuously structured bulks, limiting the properties of many inorganic materials. It is due to the participation of inorganic ions as the classical precursors, which are less controllable in the process of material synthesis. Although numerous non-classical precursors, such as pre-nucleation clusters, dense liquid phases and polymer-induced liquid precursors have been discovered, they are still uncontrollable during non-classical crystallization. In contrast, polymers can be continuously and malleably constructed through controllable polymerization and crosslinking of their monomer precursors, which expand the applications of polymeric materials. It indicates that a controllable inorganic precursor is the key to regulating the synthesizing process of a material. Inspired by the capping strategy in polymer chemistry, the hydrogen-bond based capping strategy on inorganic ionic oligomers is established. Typically, the calcium carbonate (CaCO3) ionic oligomers end-capped by triethylamine (TEA) is presented, and these oligomers have 3−11 repeated CaCO3 units with an average length of ~1.2 nm. The CaCO3 ionic oligomers can act as the inorganic monomers to replace traditional ions as precursors. And the removal of TEA initiates the polymerization and crosslinking of inorganic ionic substances. This strategy has generality and this achievement can be used to produce inorganic materials in a way analogous to polymers. The polymerization and crosslinking of inorganic ionic oligomers can be the fundamental way for advanced material preparation. It demonstrates the moldable construction of inorganic materials from nano-scales to macro-scales, and even the building of single crystals. And it is readily for the reconstruction of hierarchical structured bio-tissues, such as sea urchin spine and human enamel. Moreover, the organic-inorganic co-polymerization is established by using inorganic ionic oligomers, which enables the doping of molecular scaled inorganics into organic polymers. The incorporation of inorganic ionic oligomers into organic polymers enables the construction of biomimetic hybrid materials, improving the functions of polymers. The establishment of polymerization and crosslinking of inorganic ionic oligomers promote the fusion of polymer and inorganic chemistry. However, this is a newly raised field in chemistry, which needs further detailed investigations. It is believed that this achievement will provide more strategies for functional material production in the future.关键词：Precursors;Inorganic ionic oligomers;Polymerization and crosslinking;Organic-inorganic composite;Biomimetic materials
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发布时间：2021-11-03 - 摘要：Polymer crystallization still remains one of the most important and challenging issues of polymer physics. As crystallization process of polymers is complex and variable under different conditions, it is necessary to establish the direct structure-property relationship of polymers and realize the purposeful crystalline structure regulation of polymers. Herein, taking several typical polymers as examples, we summarize the research progresses on the crystallization behavior and the multiscale structure control of semi-crystalline polymers. Based on the research work of our group, the emphasis of this feature article is especially focused on the crystallization and structure regulation of polymers in confined spaces, e.g., in ultrathin film and nanoporous channels, and from preordered melts. The crystallization mechanism is discussed. In addition, challenging and scientific problems existing in the field of polymer crystallization and multiscale structure regulation, which may guide the future development direction of this field, have been described.关键词：Polymer crystallization;Multiscale structure regulation;Confinement effect;Pre-ordered melting molecular chains
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发布时间：2021-11-03 - 摘要：Photoinduced crosslinking polymerization (PCP) is a novel technology for the preparation of hydrogel. During PCP, the precursors polymerize in situ under ambient conditions, and the polymerization rate as well as the conversion of reactive groups can be remotely controlled by changing the position, wavelength, and intensity of the light source. Due to these characters, the hydrogel prepared via PCP has shown great potential for biomedical applications, such as 3D cell culture, tissue engineering, regenerative medicine, etc. The typical PCP types for hydrogel preparation include photoinduced free radical reactions, photoinduced click reactions, and photoinduced coupling reactions. This review explores the strengths and weaknesses of each PCP type and the biomedical applications of the hydrogels prepared via PCP. Moreover, this review also discusses the research progress of our group about the preparation of hydrogel via the photo activation of photocage to induce coupling reaction named as “photoinduced coupling reaction”. This technology exhibits the advantages of low toxicity and excellent controllability during crosslinking, and the prepared hydrogel shows strong adhesion to tissue, and thus is promising for the practical biomedical applications.关键词：Hydrogel;Photoinduced crosslinking;Coupling reaction;Tissue adhesion;Clinical transformation
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发布时间：2021-11-03 - 摘要：Solution-processed polymer solar cells (PSCs), which convert solar energy into electronic energy, have been widely recognized as a promising renewable energy technology owing to their unique features of light weight, flexibility, semitransparency, and environmental friendliness. Organic photovoltaic materials are the key components which determine the performance of PSCs. During the past few years, the emergence of nonfullerene acceptors combined with the rational design of conjugated polymer donor materials dominates the rapid development of state-of-the-art PSCs. Basically, the rational manipulation of energy levels, absorption features, as well as molecular packing and aggregations of organic semiconductors are critical to design high-performance photovoltaic materials. This review focuses on our recent progress in developing high-performance donor and acceptor materials for PSCs in terms of energy levels manipulation for organic semiconductors and morphology optimization in photoactive layer. Firstly, we demonstrate that the engineering of alkylthio side chains is an effective and universal approach to tune the energy levels of photovoltaic materials for improving the open-circuit voltage, and thus the power-conversion efficiency of PSCs. On the other hand, representative examples are given and discussed to demonstrate the effectiveness of morphology optimization in photoactive layer by rational molecular design of photovoltaic materials. Additionally, the challenges in organic photovoltaic are summarized and discussed.关键词：Organic solar cells;Bulk-heterojunction;Donor materials;Acceptor materials;Power-conversion efficiency
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发布时间：2021-11-03
Feature Articles
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