Preparation and Study of the Electro-optical Properties of Binary Mixtures of Orthoconic Anti-ferroelectric Esters and Achiral Phenyl Pyrimidine Liquid Crystal

Abstract

We have prepared three different binary systems by mixing an achiral low viscous phenyl pyrimidine liquid crystalline SmC compound with three different orthoconic antiferroelectric analogous of (S)MHPOBC exhibiting SmA*-SmC*-SmCA* phase sequences. In these binary mixtures, ferroelectric and antiferroelectric phases were induced and their mesomorphic parameters (spontaneous polarization, response time, effective torsional viscosity, and anchoring energy coefficient) were determined by thermo-microscopic and electro-optical study. All the physical parameters show a nonadditive behavior with respect to the concentration of chiral mesogens due to strong dipole-dipole and/or intermolecular interactions between polar fluorinated chiral esters with heterocyclic phenyl pyrimidine compound. Interestingly the achiral mesogen reduces the response time of these binary mixtures at the cost of lower Ps. Therefore, these mixtures can be useful for high speed technological applications where low polarization, long pitch, and very fast switching ferro or anti-ferroelectric liquid crystal mixtures are desirable.