The effects of ester substitution and alkyl chain length on the properties of poly(thiophene)s

Ester substituted thiophenes were prepared and were oxidatively polymerized to give ester substituted polythiophenes. The alkyl ester substituted polythiophenes were soluble in THF and CHCl3. The introduction of ester group resulted in blue shift in the the UV-vis absorption spectra which indicated shortening of the conjugating lengths of thiophene rings. Also, ester substitution in the side chain imparted polar characters to poly(alkylthiophene)s. X-ray study showed that the interchain distances increased linearly as the alkyl chain length increases.