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

Spectrochim Acta A Mol Biomol Spectrosc. 2007 Mar;66(3):781-5. doi: 10.1016/j.saa.2006.04.026. Epub 2006 Jul 26.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biphenyl Compounds / chemistry*
  • Liquid Crystals / chemistry*
  • Spectrum Analysis
  • Static Electricity
  • Time Factors

Substances

  • Biphenyl Compounds