Investigation of electrochemical copolymerisation of hydroxmethyl substituted 3,4-ethylenedioxythiophene with bithiophene

•Copolymerisation is enhanced by similar oxidation potential of monomers.•High upper potential boundary during electropolymerisation leads to overoxidation of pEDOT_OH.•Increase the upper potential boundary favours incorporation of BTh unit into the copolymer chain. The results of electrochemical copolymerisation of hydroksymethyl EDOT with bithiophene unit were presented. The obtained copolymers were characterised by FTIR ATR and MALDI TOF techniques. Successful copolymer growth was observed with a wide distribution of the polymer chain length, while increasing the upper potential boundary favours incorporation of BTh unit into the copolymer chain. The FTIR ATR spectra of the homo- and copolymers preset bands indicating α–α′ coupling of radical cations during (co) polymerization. The presence of bithiophene molecules improves stability of the forming polymer matrix. The results confirmed copolymeric layer formation which composition is dependent on the applied potential boundary.