Spectroscopy of PVK-phenyl derivatives disturbed the long-range ordering of liquid crystalline phase

It has been shown that replacing of O–CH3 substituents in PVK-phenyl derivative chromophores by C–N groups leads to appearance of long-ranged dipole–dipole interactions in the composites including PVK-CN, fullerenes and cyano-biphenyl derivatives. Following quantum chemical calculations it has been demonstrated that interaction of the chromophores with the LC matrices favors dipole–dipole ordering, however it description requires to take into account non-homogenous space charge density distribution. During doping by PVK-CN derivatives phase transition has been found from uniaxial system with pure nematic to the quasi-smectic LC state with the substantially different parameter of ordering. Moreover it was established that during this substitution the switching times drastically jump from millisecond to microsecond regime.