SOLVATOCHROMISM IN POLY[3-(10-HYDROXYDECYL)]THIOPHENE - A SPECTROKINETIC STUDY OF THE CONFORMATIONAL TRANSITION

The solvatochromic conformational transformation of electroconductive poly[3-(10-hydroxydecyl)]thiophene in dimethylpropyleneurea solution, due to the addition of poor solvent, was investigated. A red shift of 80 nm in the ultraviolet-visible absorption maximum suggests a much mo re extended conjugated pi-system for the new conformation. The time sc ale of this change allows a spectrokinetic analysis as a function of t he type and amount of poor solvent. Second-order reaction kinetics are evident in all cases, and this is interpreted within the framework of an intrachain rearrangement leading to a higher coplanarity of thioph ene rings in the new phase. A solid phase, laid down at very long time s, gives insight about the final steps of an association process. Copy right (C) 1996 Elsevier Science Ltd.