导电聚合物基电致变色器件的研究进展

导电聚合物作为电致变色活性材料是目前最有应用前景的智能材料之一。本文概述了电致变色器件的基本结构和导电聚合物的电致变色机理,着重介绍了多种导电聚合物基电致变色器件的特点、组成及制备,并展望了未来电致变色器件的发展及应用趋势。     

基于原位聚合离子液体凝胶的固态电致变色器件的制备及性能研究

本文通过在离子液体BmimPF6中原位热聚合甲基丙烯酸甲酯得到了透明的离子液体凝胶。通过交流阻抗测定,当BmimPF6与甲基丙烯酸甲酯的质量比为5∶1时,离子液体凝胶的导电率为1.33×10-3Scm-1。将通过电化学沉积制得的三氧化钨(WO3)和普鲁士蓝(PB)修饰FTO电极,与上述离子液体凝胶一起组装得到了全固态的电致变色器件。原位吸收光谱数据显示所制得的电致变色器件,在±2V的工作电压下,具有稳定的电致变色响应,其着色和褪色时间分别为4.5s和4.0s,着色效率达190cm2C-1(λ=660nm)。     

Comparative study of optical kinetics in single and dual poly3-methylthiophene-based solid electrochromic devices

An electrochemically deposited poly3-methylthiophene (P3MT) thin film has been used as the primary electrochromic element in a solid two-electrode electrochromic device (ECD) with a viscous polymeric electrolyte (PE) of polymethyl methacrylate and lithium perchlorate co-dissolved in ethylene and propylene carbonates. The counter-electrode of the ECD was a transparent conductive (indium-tin oxide, ITO) glass (single ECD) or a polyaniline (PANI)-coated ITO glass (dual ECD). Dual P3MT-PANI-based ECDs exhibit a lower optical switch potential (less than 0.5 V) and a faster color change speed (around 1 s) compared with the single devices, independent on the lithium salt concentration and the viscosity of the polymeric electrolyte. Electrochemical impedance spectra of both types of ECDs were analyzed at zero bias. It indicates that the use of the secondary electroactive element leads to a lower counter-ion diffusion resistance as well as to a larger counter-ion storage capacity in the electrochromic element/polymeric electrolyte interfaces. Consequently, the oxidation–reduction potential is lower, and the charge transfer process is faster in the dual devices than those in the single ones.     

All-inorganic solid-state electrochromic devices: a review

Electrochromic devices (ECDs) are currently attracting much interest in academic and industry for both research and their commercial applications because of their controllable transmission, absorption, and/or reflectance. This paper reviews the progress that has taken place from 1969 until the year 2015 with regard to all-solid-state inorganic ECD fabrication. The main aim of this review article is to provide an easy entrance to literature of all-inorganic solid-state ECD.     

A single‐layer approach to electrochromic materials

This study is focused on the development of electrochromic (EC) materials that could be incorporated into electrically‐driven switchable devices such as electrochromogenic glasses. The ultimate goal of this research is to depart from the complexity of the EC device construction which is in use today. Such construction consists of three layers each of them incorporating a specific functionality: the electrochromophore, the electrolyte and the ion storage, assembled between two transparent or reflective electrodes. In most of these conventional devices the electrolyte layer is a liquid or a gel. Since solid‐state EC devices are of high commercial interest, we are exploring various avenues to reduce the number of layers to one layer that is all‐solid and electrochromically/electrolytically and ionically functional. The design strategy is based on the use of polymers such as poly(epichlorohydrin‐co‐ethylene oxide), poly(vinyl butyral) and poly(ethylene‐co‐methacrylic acid) ionomer, to which EC properties were introduced by grafting reactions with specifically synthesized carbazole derivatives. A combination of analytical techniques was used to characterize the monomers and the carbazole‐grafted polymers. A proof of concept was demonstrated for a single‐layer, all‐solid‐state EC device consisting of a film of poly(ECH‐co‐EO) containing pendent carbazole groups, assembled between two transparent electrodes, Sn‐doped In₂O₃ oxide‐coated glasses. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Polymer gel films with simple organic electrochromics for single-film electrochromic devices

Polymer gel films [poly(1-vinyl-2-pyrrolidinone-co-N,N′-methylenebisacrylamide) (PVPD)] which contain simple organic electrochromics [p-diacetylbenzene (p-DAB), dimethyl- or diethyl terephthalate (p-DMP or p-DEP)] are prepared and their optical responses to applied voltage are investigated. p-DAP/PVPD film is colored in green by the application of 1.2 V vs. Pt wire (quasireference electrode) across the film, and p-DMP/PVPD and p-DEP/PVPD films are colored in red by the application of ?2.5 and ?1.5 V vs. Pt, respectively. Their coloring responses are about a few seconds and the bleaching process also occurs rapidly. The films have no optical memory effect. © 1992 John Wiley & Sons, Inc.     

Study of electrochromic devices with nanocomposites polymethacrylate hydroxyethylene resin based electrolyte

This paper reports the application of a polymethacrylate hydroxyethylene resin based electrolyte in electrochromic (EC) devices. The electrolyte is characterized by electrochemical impedance spectroscopy, visible spectroscopy, TGA, DSC, and DRX and tested as an ionic conductor in an EC device with the following configuration: Substrate/IZO/WO₃/Polymer Electrolyte/(CeO₂)TiO₂/IZO/Substrate. The electrolyte presents an ionic conductivity of 10^?7 S/cm at room temperature and TGA analysis show that electrolyte is thermally degraded at 200°C. The EC device based on this polymethacrylate hydroxyethylene resin electrolyte system shows memory effect and exhibits an excellent optical density. Copyright © 2011 John Wiley & Sons, Ltd.     

Molecular Machines Working on Surfaces and at Interfaces

In the past ten years a great variety of artificial molecular machines have been constructed, and very interesting concepts for controlling molecular‐level movements by external inputs have been developed. Most of the studies, however, have been performed in solution, where the investigated systems contain a huge number of molecules which behave independently from one another because they cannot be addressed individually. Before such systems can find applications in many fields of technology, they must be interfaced with the macroscopic world by ordering them in some way so that they can behave coherently and can be addressed in space. The problem of obtaining ordered arrays of molecular machines can be addressed by a variety of techniques, which include deposition on surfaces, incorporation into polymers, organization at interfaces, and immobilization in membranes or porous materials. In the last few years, the development of scanning‐probe techniques has also enabled direct observation and manipulation of single molecular‐machine molecules on surfaces. Techniques of this kind have opened novel routes to the study of molecular machines, and have also contributed to better understanding the differences between movement at the macroscopic and molecular levels. This paper reviews some recent achievements in the field of molecular machines working on surfaces and at interfaces, as single molecules or ordered arrays. Hybrid natural–artificial machines are also discussed, and the working mechanism of some natural machines is illustrated for the purpose of comparison.     

Highly redox‐stable and electrochromic aramids with morpholinyl‐substituted triphenylamine units

A novel morpholinyl‐substituted, triphenylamine‐based diamine monomer, namely 4,4′‐diamino‐4″‐(4‐morpholinyl)triphenylamine, was synthesized and polymerized with various aromatic dicarboxylic acids via the phosphorylation polyamidation reaction leading to a series of electroactive aromatic polyamides (aramids). All aramids were readily soluble in polar organic solvents and could be solution cast into tough and flexible films with high thermal stability. Cyclic voltammograms of the aramid films on the indium‐tin oxide‐coated glass substrate exhibited a pair of reversible oxidation waves with very low onset potentials of 0.36 − 0.41 V (vs. Ag/AgCl) in acetonitrile solution. The polymer films showed reversible electrochemical oxidation accompanied by strong color changes with high coloration efficiency, high contrast ratio, and rapid switching time. The optical transmittance change (Δ%T) at 650 nm between the neutral state and the fully oxidized state is up to 90%. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1289–1298     

Triphenylamine‐based polyimides with trimethyl substituents for gas separation membrane and electrochromic applications

Two series of polyimides I – II with methyl‐substituted triphenylamine units were prepared from the diamines, 4,4′‐diamino‐2″,4″,6″‐trimethyltriphenylamine (Me₃TPA‐diamine; 1 ) and 4,4′‐diamino‐4″‐methyltriphenylamine (MeTPA‐diamine; 2 ), and two commercially available tetracarboxylic dianhydrides via a conventional two‐step chemical imidization. All the polymers were readily soluble in many polar solvents and showed useful levels of thermal stability associated with high glass transition temperatures (266–340 °C) and high char yields (higher than 49% at 800 °C in nitrogen). The polymer films showed reversible electrochemistry/electrochromism accompanied by a color change from neutral pale yellow to green oxidized form with good coloration efficiency, switching time, and stability. The CO₂ permeability coefficients (P_CO2) and permeability selectivity (P_CO2/P_CH4) for these polyimide membranes were in the range of 34.1–229.2 barrer and 21.3–28.9, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

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.     

Synthesis and electrochromic properties of aromatic polyetherimides based on a triphenylamine‐dietheramine monomer

A series of electroactive polyetherimides (PEIs) with triphenylamine (TPA) units were prepared from the polycondensation reactions of 4,4′‐bis(p‐aminophenoxy)triphenylamine with aromatic tetracarboxylic dianhydrides via a conventional two‐step technique. The PEIs showed high thermal stability, with glass‐transition temperatures of 234–282 °C and decomposition temperatures in excess of 500 °C. They showed well‐defined and reversible redox couples during both p‐ and n‐doping processes, together with multielectrochromic behaviors. These polymers exhibited enhanced redox‐stability and electrochromic performance as compared with the corresponding analogs without the phenoxy spacer between the TPA and imide units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2925–2938     

A novel high‐contrast ratio electrochromic material from spiro[cyclododecane‐1,9′‐fluorene]bicarbazole

A novel electroactive spirocyclododecylfluorene monomer named 2,7‐bis(carbazol‐9‐yl)‐9,9′‐spiro[cyclododecane‐1,9′‐fluorene] (SFC) was synthesized and electrochemically polymerized to give a very stable multi‐electrochromic polymer (poly‐SFC). Two separate oxidation processes were observed for both SFC monomer and poly‐SFC that carries two carbazole units. The polymeric film of poly‐SFC was coated onto ITO/glass surface, and it shows different colors (transparent, yellowish green, green, and dark green) upon stepwise oxidations. An electrochromic device based on poly‐SFC was assembled in the sandwich cell configuration of ITO/poly‐SFC//gel electrolyte//PEDOT/ITO. Poly‐SFC exhibits 90% of transparency at neutral state and a high contrast ratio (ΔT = 58% at 800 nm). This device constructed from it represents a response time of about 1 s, high coloration efficiency (1377 cm² C^–1) and retained its performance by 96.4% even after 1000 cycles. Exhibiting high transparency at neutral state, reversible redox behavior, resistance to overoxidation, and especially high contrast ratio at near IR region can make poly‐SFC be useful and promising candidate for electrochromic applications despite having a relatively slow response time. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

High fluorescent ethyl acrylate modified PEDOT‐MeNH2 with enhanced electrochromic performance

Two poly(2'‐aminomethyl‐3,4‐ethylenedioxythienylene) (PEDOT‐MeNH₂) derivatives were successfully synthesized by electrochemical polymerization of precursors, diethyl 3'‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl) methyl)azanediyl)dipropanoate ( monomer 1 ) and ethyl 3‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl) methyl)amino)propanoate ( monomer 2 ), respectively. Structure–property relationships of monomers and polymers, including electrochemical, optical properties, and morphology, were systematically explored. Significantly, the designed polymers exhibited red and orange emission signatures with high fluorescence quantum yields (Φ_F) of 0.044 and 0.045 compared with those of monomers; they may be used as building blocks for rational design of fluorescent materials. Moreover, cyclic voltammetry and spectroelectrochemistry studies demonstrated that poly(diethyl 3'‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methyl)azanediyl) dipropanoate) ( P1 ) and poly(ethyl 3‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methyl)amino) propanoate) ( P2 ) can be reversibly oxidized and reduced accompanied by obvious color changes from light purple to light blue for P1 , and from purple to blue for P2 . Furthermore, both P1 and P2 displayed higher optical contrasts (40–70%) in the visible region, favorable coloration efficiency (typically 50–230 cm² C^?1). From these results, the two polymers would be promising candidate materials for display applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2081–2091     

Transition-metal-templated synthesis of rotaxanes and catenanes: From small molecules to polymers

This article provides an overview of the fundamental principles of the synthesis of metallocatenanes and metallorotaxanes. It also describes the synthesis and properties of electronic conducting polymers—polypyrrole and polythiophene—built around metallocatenanes and metallorotaxanes. The particular properties of this new class of polymers, including the possibility of transmetallation reactions being performed with them and the observation of electronic coupling between the metal centers and the conducting matrix, are discussed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3470–3477, 2003     

Novel aromatic polymers from benzaldehyde and triphenylamine derivatives: Synthesis,electrochromic, and photochemical properties

A series of novel triphenylamine‐based polymers were synthesized from benzaldehyde and triphenylamine derivatives. All the polymers having high molecular weight are readily soluble in many organic solvents and could be solution‐cast into amorphous films. They had glass transition temperatures (T_gs) in the range of 193–217 °C, and 10% weight loss temperatures in excess of 475 °C. Cyclic voltammograms of all polymers showed reversible oxidation redox peaks and E_onset around 0.42–0.90 V, indicating that the polymers are electrochemically active and stable. In addition, all these polymers revealed photochemical characteristics in conformity with their electrochromic characteristics. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2118–2131, 2009     

Substituent effects on electrochemical and electrochromic properties of aromatic polyimides with 4‐(carbazol‐9‐yl)triphenylamine moieties

Three series of aromatic polyimides with 4‐(carbazol‐9‐yl)triphenylamine moieties were prepared from the polycondensation reactions of 4,4′‐diamino‐4″‐(carbazol‐9‐yl) triphenylamine (1), 4,4′‐diamino‐4″‐(3,6‐di‐tert‐butylcarbazol‐9‐yl)triphenylamine (t‐Bu‐1), and 4,4′‐diamino‐4″‐(3,6‐dimethoxycarbazol‐9‐yl)triphenylamine (MeO‐1), respectively, with various commercially available tetracarboxylic dianhydrides. In addition to high thermal stability and good film‐forming ability, the resulting polyimides exhibited an ambipolar electrochromic behavior. The polyimides based on t‐Bu‐1 and MeO‐1 revealed higher redox‐stability and enhanced electrochromic performance than the corresponding ones based on 1 because the active sites of their carbazole units are blocked with bulky t‐butyl or electron‐donating methoxy groups. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1172–1184     

Electrochromic Properties of ‘Trimeric' Thiophene‐pyrrole‐thiophene Derivative Grown from Electrodeposited 6‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)hexan‐1‐amine and its Copolymer

A centrosymmetric polymer precursor, namely 6‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)hexan‐1‐amine (TPHA), was synthesized via a Knorr–Paal reaction using 1,4‐di(2‐thienyl)‐1,4‐butanedione and hexane‐1,6‐diamine. The resultant monomer was characterized by Nuclear Magnetic Resonance (¹H‐NMR). Electroactivity of TPHA was investigated via cyclic voltammetry. The electronic structure and the nature of electrochromism in P(TPHA) and its copolymer with EDOT, (P(TPHA‐co‐EDOT)), were examined via spectroelectrochemistry studies. P(TPHA) switches between claret red neutral state and blue oxidized state. Optical response times for coloring and bleaching processes of the P(TPHA) and P(TPHA‐co‐EDOT) were found as 2.1 s and 1.6 s, respectively.

The copolymer of TPHA was used to construct dual type polymer electrochromic devices (ECDs) against poly(3,4‐ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry and electrochromic switching out of the devices were investigated.     

Synthesis and electrochromic performance of oligoaniline‐containing polyureas capped with various functional groups

Tuning the molecular structure is an effective strategy to modulate the electrochromic behaviors of conducting polymers. In this contribution, a novel oligoaniline‐containing polyurea ended with reactable isocyanate groups is designed and synthesized via nucleophilic polymerization. Then various functional groups such as o‐toluidine, poly(ethylene glycol) (PEG), ethoxysilane, and congo red (CR) are introduced as end groups to modulate the electrochromic performance. Hydrophilic PEG could improve the switching speed due to the rapid electrolyte ions diffusion into polymer film through the hydrophilic region. An enhanced switching stability is afforded by crosslinkable ethoxysilane end groups, ascribed to crosslinked densified surface and great adhesion force between the electrochromic layer and ITO substrate through the hydrolysis reaction. Moreover, an ample color change is achieved by introducing colored CR as end groups. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 412–419