Synthesis And Properties Of Triarylamine Electrochromic Materials

Electrochromism is defined as a stable and reversible optical change along with color change in a material induced by an external voltage.Electrochromic materials include inorganic and organic materials depending on the material type.The nitrogen center of electron-rich triarylamines can be easily oxidized,always being associated noticeable color changes.And triarylamines have good and reversible electrochemical properties.So triarylamine derivatives are excellent electrochromic materials,and widely used in triarylamine-based polymer electrochromic materials.In this paper,by using Buchwald-Hartwig reaction,several kinds of poly(triarylamine)s were synthesized directly via the polycondensation of aromatic primary amine with aryl bromides.The structures of these polymers were determined by FT-IR spectrometer,NMR spectroscopy and Gel permeation chromatography.The thermal properties of these polymers were investigated with thermal gravimetric analysis and differential scanning calorimetry.The electrochemical properties of these polymer films were examined by cyclic voltammetry.The electrochromic properties of these polymer films were investigated by ultraviolet-visible spectra.The influence stemed from different aromatic bromide monomers on electrochemical and electrochromic properties of these polymers were analyzed.The results showed thatthese polymers all had good thermal stabilities,electrochemical reversibilities and favorable electrochromic performances.The onset oxidation potential of the polymers synthesized from 4,4'-Dibromodiphenyl ether which had a ether bond was higher than that of the polymers synthesized from 1,4-Dibromobenzene whose structure had no ether bond.And the feature peak positions of ultraviolet absorption spectrum of the formers appeared slightly blue shift compared to the latters.