Highly processable ester-functionalized polythiophenes as valuable multifunctional and post-functionalizable conjugated polymers

A series of newly ester-substituted polyalkylthiophenes (PATEs) was prepared. All polymers were fully soluble in common organic solvents, which allowed for a wide range of physico-chemical measurements, including solvato- and thermo-chromic, thermal, microstructural and electrical (in neutral and doped state) analyses. Marked differences were observed in the material characteristics of these polyalkylthiophene derivatives. It was thus possible to identify and describe the different properties ascribable not only to the different esteric groups in side chain but also to the different average degrees of functionalization of the thiophenic repeating units. In neutral state the PATEs of this study proved to be thermostable and soluble, while at the same time exhibiting high ordered molecular assemblies leading to high average conjugation lengths, electrical conductivities and stabilities. These polymers can also be easily and quantitatively transformed in other PAT derivatives using simple nucleophilic reactions either in solution or in solid (film) state. In view of the above and given that these polymers can be profitably and inexpensively synthesized, their future use for innovative applications in the field of synthetic metals appears feasible as from now.