The Influence of the Structural Features of Molecules on Spontaneous Polarization Value in Induced Ferroelectric Liquid Crystal Systems

Abstract

The occurrence of the large value of spontaneous polarization is established in LC system whose composition`s molecular structure does not satisfy the obligatory conditions for the occurrence of spontaneous polarization that are imposed by theory on a molecular structure. The essential role of short range intermolecular forces in the process of ferroelectric phase transition in the studied LC systems is shown. It was found that for {CC}, {DD} and {AD} interactions the most beneficial molecules` packing in terms of energy is the antiparallel one . In the case of {AA} and {AC} interactions both parallel and are equally beneficial in terms of energy. The possibility of formation of molecular clusters–dimers is shown. It is concluded that these are stabilized, in particular, by dipole–dipole interaction of molecules. A dimer model for increasing the value of spontaneous polarization is proposed.

Molecular mechanism of smectisation and regulation of polymorphism in nematic liquid crystal systems

“…The creation of such charge transfer complexes is a powerful and flexible instrument for modifying the structures and properties compared to those of the initial components [1][2][3]. In [4][5][6][7][8] the study of the molecular structure of nematic liquid crystal (NLC) systems that are based on polar liquid crystals, whose molecules have a large dipole moment directed along the long axis of the molecule (such as 4-n-buthyl-4 ′ -n ′ -heptanoiloxyazoxybenzene; n-cyanophenyl ester of n ′ -heptylbenzoic acid) as well as the investigation of a specific intermolecular interaction -the formation of charge transfer complexing (CTC) in LC systems were carried out by EPR, UV and IR spectroscopy.…”

“…Building upon our previous investigations into the dynamic processes involved in phase transitions and structural transformations in NLC systems [4,5], this study explores the application of catastrophe theory to describe the molecular mechanism of smectisation and the regulation of polymorphism in NLC systems.…”