Phase diagram of bicomponent mixtures of liquid crystals: Cholesteryl myristate and decyloxybenzoic acid

Abstract

Mixtures of two different liquid crystals (LCs) have been used to formulate a technologically viable LC operating at room temperature. Cholesteryl myristate (ChM) and decyloxybenzoic acid (DOBA) have been mixed in different molar ratios. Pure DOBA exhibits smectic C (SmC) and nematic (N) mesophases while pure ChM shows smectic A (SmA) and cholesteric (N*) mesophases. Transition temperatures have been determined using differential scanning calorimetry. Phase identification has been done using optical polarizing microscopy. Phase diagram shows the eutectic composition of ChM-DOBA system in the ratio 70:30 mole %. In this system, as the addition of DOBA is increased, stability of SmA phase of ChM increases up to 56 mole % of DOBA but as the addition of DOBA increases from 56 mole %, stability of SmA phase of ChM decreases and completely vanishes at about 80 mole % of DOBA. Range of SmC phase of DOBA (approximately 23°C) decreases rapidly with the addition of ChM and disappears at about 15 mole % of ChM. The maximum range of cholesteric (N*) phase in the binary system as observed in the heating cycle is about 24°C.

Study of Intermolecular Interactions in Liquid Crystals: Para-butyl-p’-cyano-biphenyl

“…There are certain substances which do not directly pass from a crystalline solid to an isotropic liquid state and vice versa, rather adopt an intermediate structure which flows like liquids but still possesses the anisotropic physical properties similar to crystalline solids. In view of the wide-spread use of liquid crystals from industrial and technological developments to biomedical applications and display devices, the subject of liquid crystal science has attracted increasing interest of the researchers from different disciplines [1][2][3][4]. The peculiar changescharacteristics of mesomorphic behaviour which occur at phase transition, are primarily governed by the nature and strength of intermolecular interactions acting between sides of planes and ends of a pair of molecules [5].…”

Optical and Thermal Investigations of Eutectic Metallomesogen Mixtures Based on Salicylaldiaminates Metal Complexes with a Large Nematic Stability Range

“…composition of 0.25 to a eutectic stability range of 46.5 • C, much wider than that of the two components 12-8NCu and A6O-8NCu of 25.5 • C and 34.4 • C, respectively. It is well known [59,60] that mesomorphic stability depends mainly on intermolecular interactions, in which the polarity of the molecule plays a predominant role and that the latter is strictly dependent on the nature and orientation of the lateral substituents [61,62].…”