Synthesis of a dipyrromethane functionalized monomer and optoelectrochromic properties of its polymer

A dipyrromethane functionalized monomer; 5-(4-tert-butylphenyl)dipyrromethane (BPDP) was synthesized. The structure of the monomer was characterized by nuclear magnetic resonance (¹H NMR and ¹³C NMR) and Fourier transform infrared (FTIR) spectroscopies. Electrochemical polymerization of BPDP was performed in acetonitrile (AN)/LiClO₄. The resulting conducting polymer was characterized by FTIR spectroscopy and electrical conductivity measurements. Spectroelectrochemical behavior and switching ability of P(BPDP) film were investigated by UV-Vis spectroscopy. P(BPDP) revealed color changes between yellow and blue in the reduced and oxidized states, respectively. In order to investigate electrochromic properties and stability of the P(BPDP) in electrochromic device (ECDs) application, dual type polymer ECD based on P(BPDP) and poly(ethylene dioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, switching ability and stability of the devices were investigated by UV-Vis spectroscopy and cyclic voltammetry.     

Optical attenuation at the 1,550-nm wavelength in a reflective mode using electrochromic ruthenium complex film

Thin films of a dinuclear ruthenium complex have been prepared on a reflective electrode. The complex is redox-active in the near infrared spectral region. Electrochromic switching between the two oxidation states of the complex film gave 80% optical contrast at the telecommunication wavelength of 1,550 nm, which translates to an intrinsic attenuation of 17.5 dB/μm of the active material. Chronoamperometric study showed excellent stability over extended switching cycles as well as retaining high attenuation with a 5-s stepping time.     

固态聚苯胺电致变色器件的制备和性能

采用CeO2-TiO2复合物薄膜作为聚苯胺电致变色器件的对电极, 选用聚合物固态电解质(PE: PMMA-PC-EC-LiClO4), 构筑了新型双层结构(Dual-type)聚苯胺(PANI)固态电致变色(EC)器件. 用电化学现场紫外-可见光谱法表征了该EC器件(ITO|PANI||PE||CeO2-TiO2|ITO)的电致变色性能, 并与单层结构(Single-type)EC器件(ITO|PANI||PE|| ITO)进行了比较. 研究结果表明, 双层结构EC器件比单层结构EC器件的电致变色性能好, 如响应速度快, 循环寿命长. 同时, 考察了电解质组分对聚苯胺电致变色稳定性的影响. EC器件(ITO|PANI||PE||CeO2-TiO2|ITO)的颜色呈现由透明的黄色(-1.5 V, PANI vs. CeO2-TiO2)到蓝色(1.0 V)的可逆变化, 在700 nm处的透射率由42.19%变到13.35%, 经过150个循环, 其透射率差仍保持不变, 着色效率为152.1 cm2/C.     

A Cheap Amperometric and Optical Sensor for Glucose Determination

A cheap amperometric and optical sensor for glucose, based on an ITO electrode coated with electrodeposited Co/Al hydrotalcite (HT) is described. Cobalt based HT shows a reversible electrochromic behavior which can be exploited for the development of an optical sensor. Working in the optical mode, the linearity range of the sensor is between 0.008 and 0.13 mM with a sensitivity of 1.14 mM^?1?cm^?2, whereas when working in the amperometric mode, the linearity ranges from 0.002 to 1.5 mM with a sensitivity of 4.24×10^?4 A?mM^?1?cm^?2. The sensor has been successfully employed for the determination of glucose in a serum sample.     

Living Cationic Polymerization of α-Methylstyrene. 2. Synthesis of Block and Random Copolymers with 2-Chloroethyl Vinyl Ether and End-Functionauzed Polymers†

Abstract

Both AB and BA block copolymers of α-methylstyrene (αMeSt) and 2-chloroethyl vinyl ether (CEVE) were synthesized by the sequential living cationic polymerization initiated with the HCl-CEVE adduct (1a)/SnBr₄ system in CH₂Cl₂ at -78°C. αMeSt-CEVE (AB) block copolymers with narrow molecular weight distributions ([Mbar]_w/[Mbar]_n ～ 1.15) were obtained when αMeSt was polymerized first, followed by addition of CEVE to the resulting αMeSt living polymer solution. The reverse order of monomer addition, from CEVE to αMeSt, also led to a BA-type block copolymer. In the polymerization of a mixture of the two monomers, almost random copolymers were obtained. Living polymerizations of αMeSt were also induced with functional initiating systems, HCl-functionalized vinyl ether adducts (1b-1d)/SnBr₄, to give end-function-alized poly(αMeSt)s with a methacrylate, an acetate, or a phthalimide terminal.     

TiO2-PTPAT纳米核/壳结构复合膜的制备及电致变色性能

通过水热法在氟掺杂氧化锡(FTO)导电玻璃基底上制备了垂直生长的二氧化钛(TiO₂)纳米棒阵列, 以TiO₂纳米棒阵列为模板采用电化学聚合法, 原位制备了TiO₂-聚三[2-(4-噻吩)苯]胺(PTPAT)纳米核/壳结构的复合薄膜, 相比于纯PTPAT薄膜, TiO₂-PTPAT复合薄膜显示出更好的电致变色(EC)性能. PTPAT薄膜在600 nm波长下的对比度为28%, 在1100 nm波长下的对比度为60%, 其褪色时间为3.86 s, 着色时间为5.52 s; TiO₂- PTPAT复合薄膜在600 nm波长下的对比度为43%, 在1100 nm波长下的对比度为79%, 其褪色时间为3.35 s, 着色时间为4.43 s, 表明核/壳复合结构薄膜的光学对比度和响应时间性能更加优异. 将PTPAT薄膜和TiO₂-PTPAT复合薄膜作为电致变色层组装成固态EC器件, 基于复合薄膜的器件具有更好的循环稳定性和更高的耐受电压. 复合薄膜在保持PTPAT薄膜原有的EC性能的基础上, 由于有序生长的纳米阵列结构的引入增加了薄膜的比表面积, 为电致变色过程中离子的掺杂和脱掺杂提供了更多有序通道, 从而加快了离子扩散速度. TiO₂阵列的引入也改善了聚合物薄膜与透明导电电极之间的界面结合情况, 从而提升了器件的稳定性.     

Advanced electrochromic/electrofluorochromic poly(amic acid) toward the colorimetric/fluorometric dual-determination of glycosuria

The electrochromic/electrofluorochromic (EC/EFC) dual-functional polymers have gained intense attention owing to the unique electrochemically induced absorption and emission change simultaneously. Most of the efforts have recently been devoted to improving their EC/EFC performance. However, the practical application studies of the EC/EFC polymers are still in their infancy. Herein, we present a poly(amic acid) based material bearing high solid fluorescence-efficiency AIEgens and electroactive oligoaniline groups, featuring a good electrochromic performance with desirable optical contrast, high coloration efficiency, and outstanding durability. This occurs in tandem with electrofluorochromic behavior with ideal fluorescence contrast and moderate switching speed. By virtue of the versatile electrospinning technique, we manufactured a nanofibrous test strip base on the resultant polymer for glucose determination. The colorimetric/fluorometric dual-determination of glucose is carried out with an obvious color change from gray to dark green, along with a drastic fluorescence change from light to dark, which exhibits numerous advantages of easy operation, rapid detection, favorable selectivity, and unique repeated use feature. Furthermore, the nanofibrous test strips also provide reliable results in the glycosuria test. This strategy shows distinct promise for future sensing applications.     

A greener electrochromic liquid crystal based on ionic liquid electrolytes

An electrochromic liquid crystal (ECLC) material composed of only liquid crystal (LC) and ionic liquid (IL) was developed. The LC containing the substituted diphenylacetylene serves as electrochromic (EC) material to realise transmittance and colour change under the direct current (DC) field, while the IL with the designable cation and anion served as electrolyte. Herein, a series of IL electrolytes was screened to investigate how IL tunes the electro-optic performance of the ECLC cell. By testing the electrochemistry window of ILs in EC cells, IL with the [NTf₂]^? anion shows adequate electrochemical stability when the EC material undergoes oxidation and reduction. The electro-optic performance of ECLC containing 1-ethoxy-4-[2-(4-pentylphenyl) ethynyl]-benzene (PEB) and IL was then evaluated by UV-vis spectrometry under the control of an electrochemical work station. Compared with other PEB-IL, PEB-[Bmim][NTf₂] with [Bmim][NTf₂] electrolyte shows a satisfactory transmittance at low operating voltage. Furthermore, Pd NPs in situ formed in [Bmim][NTf₂] reduced the EC potential and improved the light scattering of the ECLC cell. In this work, we also designed a bifunctional device based on polymer dispersed liquid crystal (PDLC) that hosts electrochromic guest molecules, and analysed the electro-optical and electrochromic properties of LC electrolyte mixtures, in order to gain control of the incident daylight and glare in building and automotive applications.     

多酸/邻菲罗啉钌LBL薄膜的制备及电化学调控荧光开关性能

通过层层静电自组装技术制备了基于电致变色多酸P_8W_(48)与发光邻菲罗啉钌Ru(phen)的杂化红光薄膜[(PEI/P_8W_(48))_m/PEI/PSS/Ru(phen)/PSS]_(15)[m=1,3,5;PEI=聚乙烯亚胺;PSS=聚(4-苯乙烯磺酸钠)].利用紫外-可见光谱对薄膜的组成及增长进行了表征;通过循环伏安法对薄膜的电化学氧化还原性质进行了考察;通过荧光光谱对薄膜的发光性质进行了研究.结果表明,薄膜在外加氧化还原电位下呈现出可逆的电致变色-荧光开关性质;在阶跃电位-0.85 V/0.85 V下循环50次,其电致变色及荧光开关性能没有明显的减弱,体现了良好的电化学稳定性.     

Electrochromic properties of anodically grown mixed V2O5–TiO2 nanotubes

Mixed V₂O₅–TiO₂ nanotube arrays were fabricated by self-organizing anodization of different Ti–V alloys. The mixed oxide nanotubes show switchable V-oxidation states and strong cathodic coloration. Already a low V content of ≈ 0.2 at.% significantly increases the electrochromic switching properties. Using a sample with 3 at.% V, very high electrochromic contrast can be established and a significantly lower switching onset voltage than for pure TiO₂ nanotubes is observed. At high V contents, although charge storage is increased, the improvement of contrast is diminished due to the strong background color of the sample.