Preparation and properties of fractionated regioregular poly(3-alkylthiophenes)

In order to establish the influence of end groups on the spectroscopic and electrochemical properties of regioregular poly(3-alkylthiophenes) we have fractionated poly(3-hexylthiophene) into four fractions differing in their molecular weight (M-n) and exhibiting relatively low polydispersity coeffic ients. Spectroscopic and spectroelectrochemical properties of the obtained fractions depend strongly on M-n. In particular, the solvatochromic effect observed in UV-vis-NIR increases with the increase of M-n whereas the poten tial of the onset of the oxidative doping decreases with the increase of M- n as evidenced by cyclic voltammetry and UV-vis-NIR spectoelectrochemistry.