Synthesis of new materials based on polythiophenes substituted with mesogen groups

A new family of conjugated polymers formed by 3-alkyloximethylthiophenes substituted with a biphenyl group was synthesised by a route involving first the coupling of a functionalised alkyl chain, from 8 to 12 carbon atoms, to 3-methanolthiophene, and then the attachment of the mesogen group. The monomer was characterised by conventional techniques, and thermal studies were also achieved. The polymerisation of these units was carried out via oxidative polymerisation with FeCl₃. The resultant polymers were characterised by FT-IR, elemental microanalysis and XPS. Subsequently, these materials were doped with I₂ and characterised by the above techniques and conductivity measurements, which indicated that these materials are in the semiconductor range. The polymerisation of these monomers was also carried out via electrochemical methods, and it was found that, together with the oxidation of the thiophene ring, the oxidation of the biphenyl group is also produced, for which an over-oxidised material is obtained, as demonstrated by XPS analysis and theoretical calculations.