Highly stable anodic green electrochromic aromatic polyamides: synthesis and electrochromic properties
作者:Cha-Wen Chang、Guey-Sheng Liou、Sheng-Huei Hsiao
DOI:10.1039/b613140a
日期:——
A 4-methoxy-substituted triphenylamine containing the aromatic diamine, 4,4′-diamino-4″-methoxytriphenylamine (2), was synthesized by the caesium fluoride-mediated condensation of p-anisidine with 4-fluoronitrobenzene, followed by palladium-catalyzed hydrazine reduction of the dinitro intermediate. A series of new polyamides with pendent 4-methoxy-substituted triphenylamine (TPA) units having inherent viscosities of 0.27–1.39 dL g−1 were prepared via the direct phosphorylation polycondensation of various dicarboxylic acids and the diamine (2). All the polymers were readily soluble in many organic solvents, such as N-methyl-2-pyrrolidinone (NMP) and N,N-dimethylacetamide (DMAc), and could be solution-cast into tough and flexible polymer films. These aromatic polyamides had useful levels of thermal stability associated with their relatively high softening temperature (242–282 °C), 10% weight-loss temperatures in excess of 470 °C, and char yields at 800 °C in nitrogen higher than 60%. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium-tin oxide (ITO)-coated glass substrate exhibited reversible oxidation at 0.73–0.79 V versus Ag/AgCl in acetonitrile solution, and revealed excellent stability of electrochromic characteristics with a color change from colorless to green at applied potentials ranging from 0.00 to 1.05 V. These anodically polymeric electrochromic materials not only showed excellent reversible electrochromic stability with good green coloration efficiency (CE = 374 cm2 C−1) but also exhibited high contrast of optical transmittance change (ΔT %) up to 85% at 787 nm and 30% at 391 nm. After over 1000 cyclic switches, the polymer films still exhibited excellent stability of electrochromic characteristics.
合成了一种含有芳香族二胺的4-甲氧基取代三苯胺,4,4′-二氨基-4″-甲氧基三苯胺(2),其合成方法为用氟化铯促进对氨基苯甲醚与4-氟硝基苯的缩合反应,随后通过钯催化的肼还原二硝基中间体。通过不同二羧酸与二胺(2)的直接磷酸化缩聚反应,制备了一系列新型聚酰胺,这些聚酰胺具有悬挂的4-甲氧基取代三苯胺(TPA)单元,固有粘度为0.27–1.39 dL g−1。所有聚合物在多种有机溶剂中易于溶解,如N-甲基-2-吡咯烷酮(NMP)和N,N-二甲基乙酰胺(DMAc),并可溶液铸造成坚韧且柔韧的聚合物薄膜。这些芳香族聚酰胺具有实用的热稳定性,其软化温度较高(242–282 °C),10%失重温度超过470 °C,并且在800 °C时在氮气中产炭率超过60%。通过电化学和光谱电化学方法研究了其载流子传输和电致变色特性。铸在铟锡氧化物(ITO)涂层玻璃基材上的聚酰胺薄膜的循环伏安图在0.73–0.79 V(相对于Ag/AgCl)时显示出可逆氧化,且在施加电压范围从0.00到1.05 V时,电致变色特性表现出优异的稳定性,颜色从无色变为绿色。这些阳极聚合电致变色材料不仅表现出优良的可逆电致变色稳定性和良好的绿色着色效率(CE = 374 cm² C−1),而且在787 nm时光学透过率变化的对比度高达85%,在391 nm时达到30%。经过超过1000次循环切换,聚合物薄膜仍表现出优异的电致变色特性稳定性。