Raman studies of polythiophene-tetraaniline hybrid polymer

Soluble hybrid polymers combining properties of polythiophenes and polyaniline can be prepared by co-polymerization of 3-alkylthiophenes and thiophene functionalized with oligoaniline at the 3-position. Electrochemical oxidative doping of poly(3-octylthiophene-co-3-oligoanilinethiophene) can be conveniently monitored by Raman spectroscopy, provided that 1064 nm excitation line is used. This excitation line strongly enhances Raman bands originating from the vibrations in doped polymer segments due to resonance effects. Raman spectroelectrochemical results unequivocally show that the electrochemical doping is sequential i.e. starts by the oxidation of the oligoaniline lateral groups and is followed by the oxidation of 2,5-thienylene main chain.