Electrochemical quartz crystal microbalance studies of polymerization and redox process of poly(1,8-diaminocarbazole) in protic and aprotic solutions

Electropolymerization and doping/undoping process of poly(1,8-diaminocarbazole) (PDACz) were investigated by cyclic voltammetry combined with electrochemical quartz microbalance (EQCM), in aqueous solution of 0.1 M HClO4 and in 0.1 M LiClO4 in acetonitrile. The results demonstrated that protonation of the polymer in HClO4 strongly influences the gravimetric response obtained during polymerization as well as the mechanism of redox process of the polymer in the monomer-free solution. The data are discussed in terms of the presence of protons and ClO4− counter ions in the reduced (neutral) polymer matrix. In aprotic acetonitrile containing LiClO4 as the supporting electrolyte, the polymer doping/undoping occurs according to the simple mechanism with exchange of anions. The gravimetric results obtained in acidic aqueous solution allowed for some revision of the scheme of the redox process proposed by the authors in the previous paper.