Optical and thermal studies on binary liquid crystal mixture

Abstract

The novel binaryliquid crystal mixture is designed and synthesized from 4-methoxycinnamic acid (MCA) and 4-ethoxycinnamic acid (ECA). Quantum chemical (DFT) calculation for MCA+ECA geometry is optimized by DFT/B3LYP with 6-311G (d, p) basis set and its results are good agreement with experimental data. Fourier-transform infrared spectroscopic(FT-IR) study confirm the presence of intermolecular hydrogen bond in the liquid crystal mixture .The paramorphic changes in nematic phase and thermo-optic properties of binary liquid crystal mixture isanalyzed using polarizing optical microscope (POM) and differential scanning calorimetry (DSC) techniques. A noteworthy observation in the present liquid crystal mixture possesses smectic A phase along with nematic phases. Intermolecular hydrogen bond interaction and it’s stabilization energy of present mixture is studied by natural bond orbital (NBO) analysis. Due to the transition,the presen tliquid crystal mixtur einduces smecticA phase. The molecular properties of presen t binary liquid crystal mixtureis analyzed by HOMO-LUMO and experimental UV-Visible studies. Thermal spanwidth, stability factor and quantum chemical properties of the liquid crystal mixture are calculated.Molecular electrostatic potential, mulliken atomic charge distribution of the optimized MCA+ECA geometry is also reported.