Chirality in regioregular and soluble polythiophene: An internal probe of conformational changes induced by minute solvation variation

Chirality has been used as an internal probe of structural changes accompanying micro‐aggregation of a soluble regioregular poly(alkylthiophene). First, the synthesis of new polythiophenes having long alkyl chains is described. The UV/vis and circular dichroic spectroscopy are shown to indicate that the transformation of a disordered species in solution into an ordered one in a micro‐aggregated state is a two‐step process. Tentative proposals are made about the nature of the intermediate state, which, however, remains unclear.