X-ray scattering from poly(thiophene): crystallinity and crystallographic structure

Abstract : X-ray scattering has been used to investigate the crystallinity and crystal structure of chemically coupled polythiophene. Heat treatment at elevated temperatures leads to significant increases in crystallinity (from approx. 35% as-synthesized up to approx. 56% after annealing at 380 C for 30 minutes) and coherence length indicative of chain growth and extension. Chemical analysis of the chain extended PT shows a major reduction in residual iodine content consistent with growth of the polymer chains to approximately 1200 thiophene rings. An initial model of the crystal structure of polythiophene is presented. (Author)