Synthesis and electro-optical properties of aromatic polyamides and polyimides bearing pendent 3,6-dimethoxycarbazole units

This work deals with the synthesis and characterization of a new m-phenylenediaminetype monomer with pendent 3,6-dimethoxycarbazole group, namely N-(4-(3,6-dimethoxy carbazol-9-yl)phenyl)-3,5-diaminobenzamide (2), and its derived aromatic polyamides and polyimides. New electroactive aromatic polyamides were synthesized from diamine 2 with four aromatic dicarboxylic acids via the phosphorylation polyamidation technique, and the polyimides were prepared from equimolar mixtures of 4,4'-oxydianiline and diamine 2 with four aromatic tetracarboxylic dianhydrides via a conventional two-step procedure. All the polyamides and the 6FDA-derived polyimide were readily soluble in many organic solvents and could afford strong and flexible films by solution casting. The polymers showed useful levels of thermal stability with glass-transition temperatures (T(g)s) in the range of 237-313 degrees C and 10% weight-loss temperatures in excess of 450 degrees C. All the polyamides and polyimides showed reversible electrochemical oxidation, accompanied by strong color changes. By incorporation of electron-donating methoxy groups on the electrochemically active C-3 and C-6 sites of the carbazole unit, the polymers exhibit greatly enhanced electrochemical stability and electrochromic performance in comparison with the analogs without any substituents on the carbazole unit. (C) 2015 Elsevier Ltd. All rights reserved.