Donor–Acceptor–Donor Copolymers with 3,4-Ethylenedioxythiophene Moiety: Electropolymerization and Effect on Optoelectronic and Electrochromic Properties

[Image: see text] Three random copolymers PE-co-M1, PE-co-M2, and PE-co-M3 were obtained by electrochemical polymerization of donor–acceptor–donor monomers M1, M2, and M3 with 3,4-ethylenedioxythiophene moiety, respectively, using a 1:1 molar ratio of the corresponding monomers, to find new properties and a more effective way to control the optoelectronic properties in conjugated system. For comparison purpose, polymers P1, P2, and P3 were prepared from the corresponding monomer units M1–M3, respectively, by electrochemical polymerization. We also present efficient synthesis, characterization, and comparative density functional theory (DFT) calculations of the monomers M1–M3 and polymers P1–P3. Cyclic voltammetry, spectroelectrochemistry, and electrochromic properties of all of the polymers P1–P3 and copolymers PE-co-M1, PE-co-M2, and PE-co-M3 were carried out and a throughout comparison was made. We have shown that electrochemical copolymerization is a powerful strategy to tune the highest occupied molecular orbital energy level, band gap, and color of the copolymer. Thus, this finding clearly indicates that the copolymers show significantly different optoelectronic properties compared to their constituent polymers.