Synthesis, structures, and electrochromic behaviors of poly(triarylamine)s based on 3-substituted thiophene derivatives

Two triarylamine-based polymers were synthesized by oxidative coupling reactions from 3-(N,N-diphenylamino) thiophene (3PAT) and 3-(10H-phenothiazin-10-yl) thiophene (3PTT) monomers, respectively. Distinguished from 3PAT, 3PTT has an additional sulfur atom between the two benzene rings. By using NMR spectroscopy and triarylamine control, the structures of the synthesized polymers were resolved with the aim of revealing the substitution effect. The results present that the substituent plays an important role in the chain propagation. Moreover, the triarylamine-based polymers were investigated for their solubility, thermal stability and electrochemical properties. To evaluate the electrochromism of the two different polymers, we have measured the spectroelectrochemical and electrochromic switching properties from the solution-cast films.