Synthesis and characterization of electroactive hyperbranched aromatic polyamides based on A2B-type triphenylamine moieties

Abstract

A series of electrochromic aromatic hyperbranched polyamides with electroactive triphenylamine (TPA) units were prepared from the phosphorylation polyamidation reactions of a newly A₂B type monomer, 4-amino-4′,4″-dicarboxytiphenylamine, with AB monomer and end-capping agent, respectively. These polymers were readily soluble in many organic solvents and showed useful levels of thermal stability associated with high glass-transition temperatures (201–221 °C) and high char yields (higher than 71% at 800 °C in nitrogen). The polymer films showed reversible electrochemical oxidation with a high contrast ratio in the visible region, and exhibited high coloration efficiency (CE), and high-level stability for an electrochromic operation. The polyamide P2 thin film revealed high coloration efficiency (CE = 426 cm²/C) and optical transmittance change (Δ%T = 79%) in the visible region with reversible electroactive stability (over 1000 times within 5% loss).