Structure and magnetic behavior of transition metal based ionic liquids

A series of ionic liquids containing different paramagnetic anions have been prepared and all show paramagnetic behavior with potential applications for magnetic and electrochromic switching as well as novel magnetic transport; also, the tetraalkylphosphonium-based ionic liquids reveal anomalous magnetic behavior.     

磷腈-紫精聚合物的合成与电致变色性能

以六氯环三磷腈作为核心、紫精为电致变色活性基,合成了一种新型有机-无机杂化电致变色材料六(1-乙基-4,4’-联吡啶-甲基苯氧基)环三磷腈(PHV²⁺).通过傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)及核磁共振氢谱(1H NMR)表征了PHV²⁺的结构.优良的水溶性使得该化合物可以通过简单的方法构造一个以聚乙烯醇(PVA)为凝胶基质的电致变色水凝胶,具有成本低廉及无毒害的优点.以氟掺杂氧化锡(FTO)涂层玻璃作为电极材料,PHV²⁺作为电致变色材料制备了PHV²⁺/PVA/KCl电致变色器件(PHV²⁺/PVA/KCl ECD).该电致变色器件在2. 1 V电压下由淡黄色变为紫色,颜色变化明显,并且该颜色变化可以循环500次;器件在526 nm处的光学对比度达到62. 19%.良好的电致变色性质使该化合物在电致变色器件方面具有潜在应用价值.     

无机-无机复合电致变色材料的研究进展

在外加电压的作用下,电致变色材料的光学性能（颜色、透光率等）能够可控制、可逆地变化,在节能减排领域有重要应用前景。随着相关研究的不断创新、深入和拓展,单一组分的电致变色材料因受到其自身结构和性能的限制,不能表现出人们所期望的电致变色性能,并且在结构和性能上不具有可设计和调控性,因而越来越无法满足实际应用的需求。与非复合电致变色材料相比较,复合型材料在这方面具有明显的优势,其优势体现在通过合理的材料设计,借助复合材料各组分的协调作用,充分激发各组分的优点,克服各自的缺点,可以获得结构和性能优异的电致变色材料。因此,近年来越来越多的研究聚焦于复合型电致变色材料。目前已开展研究的复合型电致变色材料的种类很多,根据复合组分是无机材料还是有机材料来对复合型电致变色材料分类的话主要可分为无机-无机复合、无机-有机复合和有机-有机复合3大类。相比有机电致变色材料,无机电致变色材料在材料成分控制、机械性能、光调制、使用稳定性、寿命等方面优势显著,因此,单一组分的和复合型的无机电致变色材料始终是本领域研究的重要方向。因此,本文致力于近年来无机-无机复合电致变色材料、器件和电解质的研究现状和未来的发展动态,对其研究进展、所存在的问题和发展趋势进行了归纳总结,为复合型电致变色材料的进一步研发和应用提供依据。     

Screen‐printable Electrochromic Polymer Inks and Ion Gel Electrolytes for the Design of Low‐power,Flexible Electrochromic Devices

We have developed electrochromic inks and electrolyte materials to enable mass production of flexible electrochromic displays (ECDs) and other optoelectronic devices by screen printing. Here we present a new screen‐printable ink incorporating electrochromic polymer, poly(3,4‐propylenedioxythiophene)bis(ethylhexyloxy), referred to here as ECP‐Magenta, and antimony‐doped tin oxide (ATO/TiO₂) particles to facilitate electron transport. Their dispersion in a P(VDF‐co‐HFP) binder leads to the formation of a new electrochromic ink that is suitable for screen printing. This strategy opens the door to the preparation of similar electrochromic inks based on other organic or polymeric compounds. This approach is scalable and can applied to different fields. Ion gels (IGs) composed of P(VDF‐co‐HFP) and room temperature ionic liquids (RTILs) are promising solid‐state electrolytes with high ionic conductivity, flexibility, elasticity and eco‐friendliness. The electrochemical features of different ion gels were analyzed as a function of composition and nature of the ionic liquid. Hence, new formulations of IGs were developed, evaluated by Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, before being incorporated into ECDs. The electrochromic performance of ECP‐Magenta ink combined with the RTIL‐based IG was evaluated by terms of spectroelectrochemistry showing that fully flexible ECD operating at voltages below 1 V can be screen‐printed.     

Inorganic electrochromic materials based on tungsten oxide and nickel oxide nanostructures

Electrochromic devices, which dynamically change color under applied potentials, are widely studied for use in energy-efficient smart windows. The operation of electrochromic materials and devices involves the gain or loss of electrons and simultaneous insertion/extraction of ions with opposite charges to balance the internal electric fields. The performance is therefore limited by kinetics of charge transport in the electrochromic materials as well as ion migration in the electrolyte, materials and at their interfaces. Nanostructured electrochromic materials have an extremely short charge transport distance facilitating charge transport in electrochromic devices and large specific surface area for interaction with electrolytes, and thus may provide fast charge and ions transport, high electrochemical activities and remarkable enhancement of electrochromic properties. The recent progress in application of nanostructures, including nanoparticles, 1D and 2D nanostructures, in metal oxide electrochromic materials and devices is reviewed. A perspective on the development trends in electrochromic materials and devices is also proposed.     

铁（Ⅱ）配位聚合物电致变色材料研究进展

电致变色是一种响应外部电刺激而发生颜色变化的现象,材料可以在不同的氧化还原状态之间进行可逆切换,从而在可见光或近红外区域产生新的吸收带。迄今为止,电致变色材料主要包括过渡金属氧化物、过渡金属配位聚合物、紫罗精、有机共轭聚合物等。过渡金属配位聚合物类电致变色材料兼具无机材料和有机材料的优点,具有广泛的应用前景。铁配位聚合物具有良好的氧化还原性质和丰富的电子跃迁,是一类性能优异的电致变色材料。本文综述了铁金属配位聚合物类电致变色材料的研究进展,主要从有机配体的臂形、种类和间隔基团等方面进行分类阐述。     

Fabricating polypyrrole/tungsten oxide hybrid based electrochromic devices using different ionic liquids

A facile approach of polypyrrole (PPy)/tungsten oxide (WO₃) composites electrosynthesized in ionic liquids for fabrication of electrochromic devices is discussed. The electrochromic properties of PPy/tungsten oxide nanocomposite films (PPy/WO₃) prepared in the presence of four different ionic liquids, 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIMBF₄), 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF₆), 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI), and 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI) were investigated in detail. Cyclic voltammetry results revealed that PPy/WO₃ nanocomposite films have much more electrochemical activity than those of WO₃ and PPy film. The electrochromic contrast, coloration efficiency, and switching speed of the composite films were determined for electrochromic characteristics. The maximum contrast and the maximum coloration efficiency values were measured as 33.25% and 227.89 cm²/C for the PPy/WO₃/BMIMTFSI composite film. Copyright © 2015 John Wiley & Sons, Ltd.     

紫精类电致变色材料的制备和机理

1,1'-二取代4,4'-联吡啶盐通常称作紫精(viologen),紫精以及接有紫精基团的聚合物（polyviologen）有优异的电致和光致变色性能,在新一代电致变色器件、显示器件和智能窗等方面有很好的应用前景。文章综述了紫精和紫精聚合物的制备、结构与性能、电致变色机理、功能器件设计以及在化学合成、纳米功能符合等方面的研究进展,并提出例如今后的重要研究方向。     

Magnetic graphene oxide modified by imidazole‐based ionic liquids for the magnetic‐based solid‐phase extraction of polysaccharides from brown alga

Magnetic graphene oxide was modified by four imidazole‐based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid‐phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. Fourier transform infrared spectroscopy, field‐emission scanning electron microscopy, and thermogravimetric analysis were applied to characterize the synthesized materials. Single‐factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid–liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid‐modified magnetic graphene oxide materials, and amount of 1‐(3‐aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution. The results indicated that 1‐(3‐aminopropyl)imidazole chloride modified magnetic graphene oxide possessed better extraction ability than graphene oxide, magnetic graphene oxide, and other three ionic‐liquid‐modified magnetic graphene oxide materials. The highest extraction recoveries of fucoidan and laminarin extracted by 1‐(3‐aminopropyl)imidazole chloride modified magnetic graphene oxide were 93.3 and 87.2%, respectively. In addition, solid materials could be separated and reused easily owing to their magnetic properties.     

Two-dimensional Covalent Organic Frameworks for Electrochromic Switching

The electrochromic materials have received immense attention for the fabrication of smart optoelectronic devices. The alteration of the redox states of the electroactive functionalities results in the color change in response to electrochemical potential. Even though transition metal oxides, redox-active small organic molecules, conducting polymers, and metallopolymers are known for electrochromism, advanced materials demonstrating multicolor switching with fast response time and high durability are of increasing demand. Recently, two-dimensional covalent organic frameworks (2D COFs) have been demonstrated as electrochromic materials due to their tunable redox functionalities with highly ordered structure and large specific surface area facilitating fast ion transport. Herein, we have discussed the mechanistic insights of electrochromism in 2D COFs and their structure-property relationship in electrochromic performance. Furthermore, the state-of-the-art knowledge for developing the electrochromic 2D COFs and their potential application in next-generation display devices are highlighted.     

Novel application of 1-/2-phenyl substituted 9,10-anthraquinones in solid electrochromic devices

1-/2-phenyl substituted 9,10-anthraquinones were synthesized via Suzuki coupling reactions of 1-/2-iodo-9,10-anthraquinones with benzeneboronic acid. They are efficient and reversible electrochromic materials and their solid electrochromic devices were prepared. When reduced, the device color of 1-phenyl-9,10-anthraquinone shifts from yellow to claret while that of 2-phenyl-9,10-anthraquinone switches from yellow-green to a dark blue-purple. Their different characteristics and behaviors in electrochromic devices are only determined by the different substituted positions of the phenyl group. They are potentially to be widely applied in commercial application for the excellent behaviors plus the inexpensive starting materials and short synthetic routes.     

Bipolar Electrode-based Electrochromic Devices for Analytical Applications – A Review

Bipolar electrode-based (BPE-based) electrochromic devices have garnered increasing attention in the past decade. These BPE-based electrochromic devices have been used for analytical health monitoring, point-of-care (POC) diagnostics, and chemical sensing. In this review, we highlight recent progress made regarding BPE-based electrochromic devices constructed for these analytical applications. Various, available electrochromic materials are summarized in the first section, after which the different device types (e. g., paper-based and self-powered) are discussed. Biological- and chemical-based analytical demonstrations of these devices are then reviewed. Finally, we conclude this review with a perspective on the future developments of BPE-based electrochromic devices in analytical applications.     

Enabling new electrochemical methods with redox-active ionic liquids

Redox-active ionic liquids are obtained by tethering an electroactive center to either the cation, the anion, or both ions in an ionic liquid. While such phases were studied back in the 1990s for their particular electrochemical behavior, they are currently under increased scrutiny for applications in electrochemical systems. This contribution identifies the redox-active ionic liquids’ most important aspects to promote their development. This article provides a review of their features and offers several design guidelines. In addition, it offers an overview of the key properties which enhance their suitability as electrolytes in electrochemical systems, with particular attention paid to lithium-ion batteries and electrochromic devices.     

Hybrid π-conjugated polymers from dibenzo pentacyclic centers:precursor design,electrosynthesis and electrochromics

π-Conjugated polymers(CPs)represent one of the quite important and rapidly growing branches of flexible electrochromic materials.Electrosynthesized hybrid CPs employing dibenzo pentacycles(fluorenes,carbazoles,dibenzothiophenes,and dibenzofuran)as the backbones have received considerable attention owing to their special structures and interesting electrochromic performances.Recent studies show that polymers from these structures exhibit decent contrast ratios,favorable coloration efficiencies,low switching voltages,fast response time,excellent stability,and color persistence.Intrinsically,their electrochromic properties significantly depend on fine-tailoring of precursor monomer structures,and polymerization techniques and conditions.This review devotes to showing a clear picture of the research progress of dibenzo pentacycle-centered CPs via electrochemical polymerization,including fluorenes,carbazoles,dibenzothiophenes,and dibenzofuran-based hybrid electrochromic polymers.Critical influences of the tailored precursor structures on their electropolymerization and resultant polymer performances are highlighted,aiming at providing an insight for the development of novel fused ring-based polymer electrochromic materials.     

Paramagnetic surface active ionic liquids: synthesis,properties, and applications

Paramagnetic surface active ionic liquids (PMSAILs) classify task-specific ionic liquids with magnetic properties by incorporating metal into the cationic or anionic part of the ionic liquid. Paramagnetic ionic liquids had long-chain either in cations or anions and showed excellent surface activity and magnetic properties without any need for the magnetic nanoparticles. These PMSAILs have inherent unique ionic liquid properties and self-assembled into various nano-aggregates such as micelles, vesicles, rod-like micelles, and etc., by modification in the structure of cations or anions. PMSAILs provide stimuli-responsive properties, which is one of the essential aspects of targeted applications. The appropriate functional tunability of anions and cations in PMSAILs leads to various multifaceted chemical and biological applications. A new emerging trend in PMSAIL research is hybridization with flexible materials. This review will mainly deal with the synthesis, characterization, and brief history of PMSAILs and their potential advantages in the various applications in micellar catalysis, purification and separation of biomolecules, compaction and decompaction of DNA, drug delivery, and other biomedical applications.     

Electrochromic Properties of Rhodium Oxide Films Prepared by Sol-gel Method

Electrochromic materials have been extensively investigated for their significant potential in information display, automotive, sensor and smart windows^[1]. Many studies have been carried out on the inorganic electrochromic materials, such as WO₃, MoO₃, NiO_x and so on^[2]. In this paper, We first report the electrochromic behavior of rhodium oxide film prepared by sol-gel method on transparent conductor substrate. The film exhibited reversible two color (from bright yellow to dark green) electrochromic behavior with satisfactory contrast at anodic and cathodic forms when the applied potential was reversed successively.     

离子液体固定化材料在固相萃取中的应用研究进展

离子液体是由阴、阳离子组成的低温熔融盐,几乎没有蒸汽压,具有稳定性好、溶解能力强、结构可设计、导电性好等优良性能.离子液体作为一种广受关注的新型“绿色溶剂”,具有代替传统有机溶剂的潜力,其制备方法和应用范围研究日趋完善和多样,已广泛应用于催化化学、光电化学、材料化学和分析化学等领域.离子液体通过功能化导向设计后,可以将...     

Wire‐Active Microrheology to Differentiate Viscoelastic Liquids from Soft Solids

Viscoelastic liquids are characterized by a finite static viscosity and a yield stress of zero, whereas soft solids have an infinite viscosity and a non‐zero yield stress. The rheological nature of viscoelastic materials has long been a challenge and is still a matter of debate. Here, we provide for the first time the constitutive equations of linear viscoelasticity for magnetic wires in yield‐stress materials, together with experimental measurements by using magnetic rotational spectroscopy (MRS). In MRS, the wires were subjected to a rotational magnetic field as a function of frequency and the motion of the wire was monitored by using time‐lapse microscopy. The studied soft solids were aqueous dispersions of gel‐forming polysaccharide (gellan gum) at concentrations above the gelification point. It was found that soft solids exhibited a clear and distinctive signature compared with viscous and viscoelastic liquids. In particular, the average wire rotation velocity equaled zero over a broad frequency range. We also showed that the MRS technique is quantitative. The equilibrium elastic modulus was retrieved from the wire oscillation amplitudes, and agrees with polymer‐dynamics theory.     

多金属氧酸盐电致变色材料

多金属氧酸盐具有多样的结构和良好的电化学可逆性,在电致变色器件(例如军事伪装、后视镜、智能窗以及高对比度信息显示器)上有着广阔的应用前景。本文综述了多金属氧酸盐在电致变色领域的研究进展情况。概述了多金属氧酸盐的电致变色机理以及制备多金属氧酸盐电致变色薄膜的方法,主要包括:溶胶-凝胶方法、电沉积法、Langmuir-Blodgett方法、层接层自组装方法。按照多金属氧酸盐的结构类型分类,结合最新文献报道,介绍了同多酸(盐)型和杂多酸(盐)型电致变色材料性能的研究现状。最后,对其未来的发展方向进行了展望。     

Electrochromic Poly(chalcogenoviologen)s as Anode Materials for High‐Performance Organic Radical Lithium‐Ion Batteries

A series of electrochromic electron‐accepting poly(chalcogenoviologen)s with multiple, stable, and reversible redox centers were used as anodic materials in organic radical lithium‐ion batteries (ORLIBs). The introduction of heavy atoms (S, Se, and Te) into the viologen scaffold significantly improved the capacity and cycling stability of the ORLIBs. Notably, the poly(Te‐BnV) anode was able to intercalate 20 Li ions and showed higher conductivity and insolubility in the electrolyte, thus contributing to a reversible capacity of 502 mAh g^?1 at 100 mA g^?1 when the Coulombic efficiency approached 100 %. The charged/discharged state of flexible electrochromic batteries fabricated from these anodic materials could be monitored visually owing to the unique electrochromic and redox properties of the materials. This study opens a promising avenue for the development of organic polymer‐based electrodes for flexible hybrid visual electronics.