Poly(4,4'-bis(thien-2-yl)azobenzene-co-3-hexylthiophene): Synthesis and optical/electrochemical properties

Abstract

A conjugated polymer of poly(4,4'-bis(thien-2-yl)azobenzene-co-3-hexylthiophene) (PTAB-H), bearing azo group in main chain and soluble in THF, chloroform, was synthesized through FeCl3 oxidation copolymerization with 3-hexylthiophene, and the monomer of 4,4'-bis(thien-2-yl)azobenzene was synthesized by Sandmeyer reaction and Suzuki reaction. The UV-Vis spectra of PTAB-H reveal that azo group in the main chain can extend the absorption and lower the band gap. The fluorescent spectra, photoluminescence (PL) spectra, cyclic voltammetry (CV) of PTAB-H were recorded.The gel permeation chromatography (GPC), thermogravimetry analysis (TGA), and differential scanning calorimetry (DSC) measurements indicated that the molecular weight Mn, Mw and polydispersity indices (PDI) of the polymer are 10 876 g/mol, 22 338 g/mol and 2.05 respectively and the temperature of 5% weight-loss is 224.6 °C. No glass transition and crystallization melting peak was observed in the temperature range from 30 °C to 400 °C.