Monodomain alignment of thermotropic fluorene copolymers

Conjugated copolymers of 9,9-dioctylfluorene alternating with benzothiadiazole and dithiophene moieties in the main chain were found to be 'hairy rod' type thermotropic liquid crystalline polymers as well as yellow to red photoluminescence emitters. Thin films of both copolymers were found to align into monodomains on standard liquid crystal alignment layers as well as on rubbed precursor route poly(para-phenylenevinylene) (precPPV), which is transparent to red light. This observation is of importance for the use of precPPV as a hole transporting alignment layer for fluorene copolymers in polarized electroluminescence devices.