13C CP-MAS NMR study of compatibility in blends of poly(3-octyl-thiophene) and poly(phenylene oxide)

Abstract Blends of undoped poly(3-octyl thiophene) and poly(phenylene oxide) have been investigated using solid-state 13 C cross-polarization magic-angle spinning (CP-MAS) NMR. Proton spin-lattice relaxation times in the rotating frame (T 1ϱ (H)) are unchanged in the blends as compared with the homopolymers. This shows that the blends are incompatible on a molecular level. The averaging of laboratory frame spin-lattice relaxation times (T 1 (H)) indicated that the maximum domain size is approximately 100 nm for POT-concentrations below 30%.