Processable and multichromic polymer of bis-3-hexylthiophene substituted 4-tert-butylphenyl quinoxaline

A new polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline (PHTQ) was synthesized by both chemical and electrochemical polymerization and its electrochemical properties were reported. The monomer was electrochemically polymerized in the presence of tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte in dichloromethane–acetonitrile (5:95, v:v). Nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) were utilized for the characterization of the monomer and the soluble polymer. The polymer was further characterized by gel permeation chromatography (GPC). Spectroelectrochemistry and switching ability of the polymer were investigated by UV–vis spectrophotometer and cyclic voltammetry. The polymer revealed three distinctive colors upon doping which indicated that the polymer is multichromic. tert-Butyl group on the pendant phenyl rings and hexyl groups on thiophene eased the solution processability of the electrochromic polymer. The electrochemical and spectral properties of the chemically synthesized polymer were investigated via spray coating on ITO glass slides.