Stability and degradation of trans-polyphenylacetylene in organic solvents and under light illumination

Abstract

The stability of a semiconducting photoconductor, trans-polyphenylacetylene (PPA), in organic solvents and under light illumination has been studied. When chloroform is used as solvent, loss of effective conjugation and decrease in molecular weight are detectable after less than an hour. The degradation is slowed down considerably at - 20°C with only minimal changes detected after 48h. On the other hand, the presence of near-UV and short wavelength visible light strongly accelerates the degradation of PPA samples in solution and of solution-cast PPA films. The photoconductivity of solution-cast PPA films decreases rapidly on illumination with near-UV and short wavelength visible light but not with red light. © 1989.