Polystyrene-graft-poly(2,2′-bithiophene): synthesis, characterization, and properties

This paper describes a new approach for graft copolymerization of 2,2′-bithiophene onto a polystyrene (PSt) backbone by a multi-step process. For this purpose, first poly(styrene-co-4-chloromethyl styrene) [P(St-co-CMSt)] was synthesized via a free radical polymerization, and then the chlorine groups of P(St-co-CMSt) copolymer were converted to thiophene groups by a substitution nucleophilic reaction in the presence of a solvent composed of 2-hydroxymethylthiophene, sodium hydride, and dry tetrahydrofuran. The thiophene-functionalized polystyrene multicenter macromonomer obtained was used in oxidative copolymerization with 2,2′-bithiophene to yield a graft copolymer [polystyrene-graft-poly(2,2′-bithiophene) (PSt-g-PBT)]. The chemical structures of all samples as representatives were characterized by 1H nuclear magnetic resonance, and Fourier transform infrared spectroscopy. The thermal behaviors of the synthesized polymers were investigated by means of thermogravimetric analysis. Moreover, the conductivity of the PSt-g-PBT copolymer was measured by four-point probe method, and its electroactivity behavior was verified under cyclic voltammetric conditions.