Design, Synthesis and Characterization of Hydrogen Bonded Binary Liquid Crystal Complex from 4-Methoxycinnamic Acid and 4-Hexyloxybenzoic Acid (4MCA:6OBA)

Abstract

Abstract Hydrogen bonded liquid crystal (HBLC) binary mixture has been synthesized from mesogenic 4-methoxycinnamic acid (4MCA) and mesogenic 4-hexyloxybenzoic acid (6OBA) with different mole ratio. The mesomorphic phase behavior and corresponding phase transition temperatures along with the enthalpy values were investigated by differential scanning calorimetry (DSC). The characteristic textures of 4MCA+6OBA binary mixture were observed by using polarizing optical microscope (POM). Fourier transform infrared spectroscopic (FT-IR) studies confirm the formation of hydrogen bond in the present binary mixture. A note worthy observation in this complex is that pure mesogens have no smectic phase where as 4MCA+6OBA binary mixture exhibits a nematic phase along with higher order smectic C (Sm C) phase. Variation of mole ratio influences thermal properties such as phase peak, enthalpy values and thermal span width of the present HBLC binary mixture complex. The optical tilt angle of 4MCA+6OBA for smectic C phase and thermal stability factors have been investigated. Optical tilt angle for smectic C phase is determined and same is fitted to a power law.