Comparative study of Shirakawa and Naarmann-Theophilou type polyacetylenes by ESR

Spin dynamics study of the neutral soliton was reported at room temperature in both Shirakwa (S-PA) and Naarmann and Theophilou (NT-PA) type polyacetylenes. Intra-chain (D∥) and inter-chain (D⊥) diffusion rates, and a residual ESR width were discussed. A qualitative difference in dimensionality of spin dynamics, as reported by Wang et al, was not observed at all. On the other hand, a weak correlation was found between D∥ and the residual ESR line width which is proportional to the number of trapping site. It is concluded that the difference of the conductivity in both polyacetylenes is dominated by the higher density of film and the higher degree of orientation in the NT-PA film than the S-PA.