Random and Regioregular Thiophene-Based Copolymers Containing Oligoaniline Side Chains: Synthesis, Spectroscopic and Spectroelectrochemical Investigations

In search for polymers with tunable spectroscopic and electrochemical properties, suitable for application in organic electronics, we have elaborated two new families of proccssible conjugated polymers containing electroactive side chain chromophores of oligoaniline type. Random copolymers of 3-alkylthiophenes and 3-oligoaniline thiophenes can be prepared in a three-step procedure. First, 3-alkylthiophene and ethyl-3-thiopheneacetate are copolymerized to give poly(3-alkyl-2,5-thienylene-co-3-methyiene-ethylcarboxylate-2,5-thienylene)-the precursor polymer. The precursor is then hydrolyzed and, in the last step, aniline oligomers are attached to it via amidation reaction. Regioregular copolymers with oligoaniline pendant groups are prepared by post-polymerization functionalization of regioregular precursor copolymers, namely poly(dialkyl-2,2′-bithiophene-alt-2,7-fluoren-9-one)s by grafting aniline oligomers via the carbonyl groups of the fluoren-9-one subunit The properties of the precursors as well as oligoaniline containing polymers are determined by electrochemical methods and UV-Vis-NIR, EPR and FTIR spectroscopy.