Electrochimica Acta, Vol.256, 119-128, 2017
Electroactive (A(3)+B-2)-type hyperbranched polyimides with highly stable and multistage electrochromic behaviors
Multicolored electrochromic materials have attracted intense attentions due to their diverse smart applications. In this work, we demonstrate a facile strategy to realize multistage visible/near-infrared (vis/NIR) electrochromism by designing and synthesizing two kinds of novel hyperbranched polyimides (HBPIs) from a novel triamine as an A(3) monomer and two dianhydrides as B-2 monomers. The resulting HBPIs exhibit excellent solubility and thermostability. Cyclic voltammograms of the HBPIs films reveal four reversible redox couples along with five color conversions (colorless-yellow-red-indigo-black). Furthermore, the HBPIs exhibit superb electrochromic performances including continuous modulation over the entire visible region, short response time, high optical contrast, high coloration efficiency, excellent switching stability and long-term optical memory. Accordingly, these HBPIs are promising materials in the applications of electrochromism and even endowing difunctionality combining with supercapacitance. (C) 2017 Elsevier Ltd. All rights reserved.