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.