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 (Mn) and exhibiting relatively low polydispersity coefficients. Spectroscopic and spectroelectrochemical properties of the obtained fractions depend strongly on Mn. In particular, the solvatochromic effect observed in UV-vis-NIR increases with the increase of Mn whereas the potential of the onset of the oxidative doping decreases with the increase of Mn as evidenced by cyclic voltammetry and UV-vis-NIR spectoelectrochemistry.