Dependence of Absorption Spectra and Solubility of Poly(3-alkylthiophene) on Molecular Structure of Solvent

Abstract

Solvatochromic shifts of spectra of solutions of poly(3-hexylthiophene) and poly(3-docosylthiophene) have been analyzed in terms of Taft linear solvation energy relationships. Color changes of solutions of the former at 25°C are primarily due to changes in normal solute-solvent interactions. On the other hand, color changes of solutions of poly(3-docosylthiophene) appear to be due to configurational changes of the polymer chain. Solubility of the polymer is affected by solvation of the alkyl groups, electron donating or Lewis basicity properties of the solvent, polarity, and molecular volume of solvent molecules.