Photodegradation and Photostablization Studies of Poly(3-Butylthiophene) in the Solid State.

A study to clarify the mechanism of the photochemical degradation of poly(3-alkylthiophene)s in the solid state was carried out. The isolation of two low molecular weight products allowed us to determine that the polymer, under irradiation of visible light, gives rise to singlet oxygen that will, in turn, cause oxidation of the polymeric chains. Furthermore, N-hexadecyl-N-methylaniline and 1-phenyldodecan-1-one were found to decrease the rate of polymer oxidation, the latter compound being more efficient than the former even at lower concentration. It is suggested the protective action by these substances may simply be due to their ability to act as a light screen.