Recent advances in the field of conducting polymers

On the occasion of the 20th anniversary of the Journal of Solid State Electrochemistry the Topical Editor of Polymer Modified Electrodes and Polyelectrolytes surveyed the fields belonging to his area. The review emphasizes the developments in the last 5 years.     

Recent advances in the design of polymers for contact lenses

Three approaches for the design of polymers for extended wear contact lenses possessing high oxygen permeability are described. These approaches include the design of high strength, high water content hydrogels, the design of low water content fluorosilicone based materials and the design of hydrogels based on methacrylate end capped hydrophilic side chain siloxanes.     

Recent advances in the anionic synthesis of chain-end functionalized polymers

Recent results for the preparation of chain-end functionalized polymers using alkyllithium-initiated anionic polymerization are described. Termination with 4-chloro-1,1,1-trimethoxybutane has been used to prepare trimethoxy ortho ester (carboxyl)-functionalized polymers. Functionalization with the oxiranes, glycidoxypropyltrimethoxysilane, 3,4-epoxy-1-butene and 1,1,1-trifluoro-2,3-epoxypropane, has been investigated to prepare trimethoxysilyl-functionalized polymers, 1,3-diene-functionalized macro monomers and trifluoromethyl-functionalized polymers, respectively. Secondary amine-functionalized polymers have been prepared by termination with N-(benzylidene)methylamine and also using an N-benzyl tertiary amine-functionalized alkyllithium initiator followed by hydrogenolysis of the benzyl group.     

Recent advances in oxygen electrocatalysts based on tunable structural polymers

Due to their high energy density, great safety and eco-friendliness, zinc-air batteries (ZABs) attract much attention. During the process of charging and discharging, the two key processes viz. oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) limit their efficiency. In general, the noble metal-based electrocatalysts (ORR: platinum (Pt); OER: iridium (IV) oxide [IrO₂] and ruthenium oxide [RuO₂]) have long been used. Nonetheless, these noble metal electrocatalysts also have their limitations owing to high cost and poor stability. As alternatives, polymers are found to be most promising on account of their tunable structure, uniform network, high surface morphology and strong durability. Polymers are capable catalysts. In this review, recent advances as well as insight into the architecture of covalent organic polymers (COPs), metal coordination polymers (MCPs) and pyrolysis-free polymers (PFPs) are duly outlined.     

片段/虚拟分子印迹聚合物的应用新进展

分子印迹聚合物(MIPs)是通过模拟酶与底物或抗原抗体特异性结合原理而制备的高分子聚合物,以其结构预定性、识别特异性、制备简便、成本低、耐受性强等优点而被广泛用于样品前处理、传感分析、生物医药、环境/食品分析等多个领域。目前已发展多种策略用于MIPs制备,达到简化制备过程或提高聚合物性能等目的,极大拓宽了MIPs的应用范围。对各种先进印迹策略及其组合使用的探索已成为MIPs制备的研究热点之一。其中,片段印迹策略和虚拟模板印迹策略备受青睐。片段印迹策略是选择目标分子中含有特定官能团的一部分(片段结构)作为模板进行印迹,通过对片段的识别达到对整个分子的识别,能够克服某些目标物不易获得或体积较大不适合作为模板的问题,为印迹易失活、易传染的目标物及整体印迹困难的大分子提供可行的方法。虚拟模板印迹策略是选用与目标物特异性结构相似或相同的其他物质代替目标物作为模板制备MIPs,可在很大程度上解决模板不易获得或较昂贵等问题,以及避免模板可能泄漏对结果造成的影响,尤其适用于目标物造价高、具有感染性、易燃易爆、易降解等不适合作为模板分子的情况。该文选取了最近4年发表在ACS、Elsevier、RSC等数据库约20篇相关文献,综述了片段/虚拟MIPs(FMIPs/DMIPs)的应用新进展。首先,针对蛋白质和微生物检测以及哺乳动物细胞印迹,介绍了FMIPs在生物医药领域的应用,另外介绍了FMIPs在食品分析领域的研究进展。随后,介绍了DMIPs在样品前处理和传感分析领域的应用。在样品前处理中,DMIPs主要作为固相萃取吸附剂进行装柱固相萃取、分散固相萃取、磁固相萃取、基质固相分散萃取等,或作为分子印迹膜材料,用于选择性萃取和富集分离样品中的目标分析物。在传感分析领域,DMIPs主要作为传感器的传感和转导元件,提高化学发光或荧光检测等方法的灵敏度和准确度。最后,对片段印迹和虚拟模板印迹策略的优缺点、区别与联系进行了总结,并展望了这两种策略的发展与应用前景。     

Recent advances in the observation of disclinations of main-chain nematic polymers

Experimental observation of disclinations of main-chain nematic polymers is reviewed. The geometry of disclination structure is discussed both from observations of schlieren texture and the theory of curvature elasticity for a two-dimensional case with equal splay and bend moduli. The effects of non-equal elastic moduli, the nature of the disclination core and the observation of inversion wails are briefly mentioned. Examples of experimental observation of disclinations of high topological strengths up to S=4 are given. The main experimental methods to map the director field around disclinations are 1) lamellar decoration, 2) band-texture decoration and 3) surface microcrack decoration. The methods are discussed and compared, and examples illustrated by electron micrographs or photomicrographs are presented.     

Review: Recent advances of one-dimensional coordination polymers as catalysts

This review aims to provide reports of one dimensional (1-D) coordination polymers that have been used as catalysts in various organic reactions in the last decade, covering the literature from 2007 and onwards. The CPs have been mainly categorized into homometallic and heterometallic compounds; additional parameters such as the metal and ligand selection for the CP are discussed to provide a more detailed look into each system.     

Recent advances in synthetic methods and applications of photo-luminescent molecularly imprinted polymers

Molecularly imprinted polymers with photo-luminescent properties (PLMIPs) and PLMIPs-based hybrids have been widely studied in recent years because of their integrated merits from molecular imprinting technologies and PL properties. PLMIPs have superior capabilities for signal transducer and molecular recognition, exhibiting great potential as the constructing platforms for promising applications. During the past decade, numerous researches have mentioned PLMIPs. In terms of unique merits and important applications of PLMIPs, a timely, comprehensive and in-depth review on PLMIPs is significant and is still lacking currently. This review systematically summarizes recent advances of PLMIPs, focusing on different synthetic methods and applications. Based on different components and structures, PLMIPs include different categories. Synthetic methods majorly involve encapsulation polymerization of nanomaterials (fluorophores) into MIPs, copolymerization of fluorescent monomers, electro-polymerization, photo-polymerization, etc. Various engineering structures and luminescence properties of PLMIPs are highlighted Potential applications of PLMIPs mention significant research fields, including chemo/bio-detection, bio-imaging, functionalized separation materials, versatile sensing materials, optical devices, etc. We also discuss present status, probable challenges and future perspectives of PLMIPs. This review is desirable for scientists from broad research fields and can promote further development of MIPs-based functional materials, luminescent hybrid materials and other advanced optical materials.     

Recent advances in single-crystalline two-dimensional polymers: Synthesis,characterization and challenges

Two-dimensional polymers (2DPs) are emerging crystalline 2D organic material comprising free-standing, single-atom/monomer-thick, planar, and covalent networks with long-ranging structural order. Benefiting from their intrinsic porosity, crystallinity, and electrical properties, 2DPs have displayed great potential for separation, energy conversion and electronic fields. In this mini review, we aim to provide the recent progress in crystalline 2DPs films form synthesis strategies to characterization methods, as well as the future trends. We first present the synthesis strategy of single-crystalline 2DPs films including crystal engineering approaches and surface science. Also, we summarize the characterization methods of 2DPs films and highlight the advantages and limitations of different methods focusing on chemical bonding, morphology, and crystal structure. Finally, we will present the current challenges and trends regarding the future developments of crystallinity, monomer design, synthesis strategy and characterization.     

Recent advances in electrochemical sensors based on chiral and nano-sized imprinted polymers

General scheme of enantiomeric molecular imprinting. Reprinted from [21^?] with permission from Elsevier.

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Recent advances of discrete coordination complexes and coordination polymers in drug delivery

Coordination complexes (including discrete coordination complexes and coordination polymers) have demonstrated excellent performance in drug delivery. This review outlines recent advances of discrete coordination complexes, bulk coordination polymers, and nanoscale/microscale coordination polymers in drug delivery. Specifically, rationale and mechanism of coordination complexes in drug delivery are summarized in this contribution. In this review, we discuss applications of these coordination species in drug delivery from perspectives in chemistry and pharmaceutical sciences, and an outlook of these coordination species of interest in drug delivery will also be proposed.     

Fast switching ferroelectric liquid-crystalline polymers

The principles of ferroelectricity, especially in liquid crystals (FLC) and polymers, are briefly presented. In a liquid-crystalline side chain polyacrylate electro-optical switching with response times of 200–400 μs was measured. Besides the ferroelectric switching an even shorter electroclinic switching process was detected. The influence of the spacer length and the molecular weight on the ferroelectric properties is discussed. The kind and number of chiral centers and their location in the side group strongly affects the electrooptical properties. In one polymer a change of the optical contrast caused by a sign reversal of the spontaneous polarization was found. In another FLC polymer three switching states (antiferroelectric behaviour) were detected. With coloured and fluorescent FLC polymers, obtained by mixing or by copolymerization new promising applications in electrooptical devices are expected.     

Fast switching ferroelectric liquid-crystalline polymers

Ferroelectric liquid-crystalline side chain polymers containing polyacrylate or polysiloxane main chains, a mesogenic unit of three aromatic cores and chiral end groups were synthesized and characterized by D.S.C., optical microscopy, and X-ray diffraction. Polyacrylates with a flexible spacer of eleven methylene groups exhibit fast bistable switching in oriented samples (2 to 4μm cells) with response times of some ms at low D.C. voltages, making these polymers interesting for the fabrication of electrooptical devices. Somewhat longer response times were found for the first switchable polysiloxanes. In this case some problems in obtaining well orientated samples have to be solved.     

Recent advances in covalent functionalization of carbon nanomaterials with polymers: Strategies and perspectives

Carbon nanomaterials (CNMs) have been proposed as promising nanofillers for polymer composites because of their high surface area, structural flexibility, good mechanical strength, and their unique thermal, optical, and electronic properties. However, the strong van der Waals interactions between individual nanoparticles have limited the manipulation of CNMs and restricted their use in many promising fields. The functionalization of CNMs has attracted great interest on synthesis of complex structures, and helped establish different facile, scalable, controllable and low-cost methods to graft well-defined polymers onto the surfaces of CNMs. This review highlights the advances made in recent years on the functionalization chemistry of carbon nanotubes and graphene with polymers by both the “grafting from” and “grafting to” techniques. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 622–631     

Modeling of hysteretic behavior in ferroelectric polymers

Controlling the polarization state of ferroelectric materials, and more particularly piezoelectric polymers, is critical to ensure good operation of actuators or sensors using such energy conversion mechanisms. More specifically, the modeling and prediction of the hysteretic behavior of such materials is a critical aspect for the fabrication of robust and accurate devices. The purpose of this article is to present a model based on mathematical functions describing hysteretic behavior as a sum of elementary polarizations arising from combined avalanche and saturation physical effects. Predicted responses show good agreement with experimental measurements, and extension of the model for taking into account electric field‐induced crystallization during operations is presented. Finally, the proposed model is simple to implement and does no require heavy computational and memory requirements, as it relies on pure mathematical functions and only requires unidimensional distribution of elementary polarizations. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 499–508     

Cooperative relaxations/transitions in ferroelectric polymers

Dielectric relaxation and thermal transitions in β-PVDF have been investigated by Thermo-Stimulated Current spectroscopy and Differential Scanning Calorimetry respectively. A comparative study of spectra and thermograms has been performed. The relaxation mode associated with the glass transition of the true amorphous phase is characterized by relaxation times obeying a compensation law due to cooperative molecular movements. A conformationally disordered structure is proposed for β-PVDF to explain thermal events occurring around 60°C. Ageing of ferroelectric properties of β-PVDF has been associated with cooperative molecular movements liberated largely below the melting point.     

Electromechanical effects in ferroelectric liquid crystalline polymers

Electric fields can induce mechanical vibrations in planar aligned sandwich cells of ferroelectric liquid crystals. Measurements on a polysiloxane and a polyacrylate side chain polymer proved that the electromechanical effect also exists in ferroelectric liquid crystalline polymers. The main characteristics of the electromechanical responses of these polymers are described and compared to the response of low molecular weight ferroelectric liquid crystals. According to the proposed interpretation, the vibrations in the direction parallel to both the smectic layers and cell substrates are due to coupling between the director rotation and the flow, while the resonances in the vibrations normal to the plates are connected to layer deformations.