Synthesis and electrochromic properties of epoxy materials containing triphenylamine units

A series of novel aromatic epoxy resins are prepared from the epichlorohydrin (ECH) and di(4-hydroxybenzylideneamino) triphenylamine (DHB-TPA) monomers, which are synthesized from different triphenylamine (TPA)-containing diamines and p-hydroxybenzaldehyde. FT-IR, ¹H NMR and UV–Vis absorption spectra are employed to characterize the chemical structures of the polymers. All the polymers are amorphous, soluble in a variety of common organic solvents. The thermal properties of the polymers are investigated by thermogravimetric analysis (TGA) indicating good thermal stabilities compared with conventional epoxy resins on behalf of the introduction of aromatic TPA groups. All the polymers exhibit excellent reversibility of electrochromic characteristics by continuous cyclic scans between 0 and 2.0 V with the color changing from green to blue. The polymers also display photoelectrical response. The above properties prove that the series of polymers exhibit high thermal stability, excellent reversibility of electrochromic characteristics and photoelectric behaviours, which can be prospective candidates as electrochromic materials and photoelectrical conversion materials.