Emission behavior of novel liquid-crystalline electroluminescent polymers

Abstract

Four kinds of novel polymers, which incorporated both oxadiazole and amine moieties as a charge-transporting emissive unit and an alkyl spacer in the same side chain, were designed and synthesized. Electroluminescent (EL) and liquid-crystalline (LC) properties of the polymers were explored.; poly(2-(4'-methacryloyloxy-n-hexyloxybiphenyl)-5-(3-N-methylcarbazol)-1,3,4-oxadiazole) and poly(2-(4'-methacryloyloxy-n-alkyloxybiphenyl)-5-(4-N,N-dimethylaminophenyl)-1,3,4-oxadiazole) (PMn-OXD-MA) showed LC phases. Furthermore, it was found that the alkyl-spacer length strongly affected the phase structure of PMn-OXD-MA; PM2-OXD-MA did not show an LC phase, but PM6-OXD-MA and PMll-OXD-MA showed a nematic and a smectic A phase, respectively.