Electrochemical copolymerization of 3‐dodecylthiophene and 3‐methylthiophene

Abstract 3‐Dodecylthiophene ( 1a ) and 3‐methylthiophene ( 1b ) were copolymerized electrochemically. The visible and IR spectra of the neutral copolymers prove the copolymers to be of random structure, which can be denoted as that of poly(3‐alkyl‐2,5‐thienylene)s. 1b polymerizes with preference over 1a . With increasing fraction of monomeric units of 1b in the copolymers, the conductivity increases and the solubility of the neutral copolymers decreases. The copolymer containing 58 mol‐% monomeric units of 1b has a high conductivity of 220 S/cm and a good solubility of 75 wt.‐% in chloroform. 1 H NMR spectra of poly(3‐dodecylthienylene) and copolymers show two chemical shifts for the α(1)‐methylene protons of the monomeric units of 1a as well as of the methyl protons of the monomeric units of 1b . This fact may be explained by the presence of head‐to‐head and other constitutions.