Mesomorphic Investigation of Binary Mixtures of Liquid Crystal Molecules with Different Mesogenic Architectonics

Abstract

Different binary phase diagrams, made from two differently substituted three-rings azo/ester and azomethine/ester compounds of the same terminal alkoxy side chain of six carbons, as opposed to the other terminal polar substituent, which can either donate electrons or withdraw electrons including H. The thermal behavior of the prepared derivatives was investigated by differential scanning calorimetry and phases identified by polarized optical microscope. The first group of the binary mixtures was made from laterally F-substituted azo/ester derivatives and their laterally neat analogues. The second group of binary mixtures was made from laterally methoxy-substituted azomethine/ester derivatives and their laterally neat analogues. The final type of investigated phase diagrams was made from the laterally substituted azo and azomethine components bearing different lateral polar groups and different mesogenic moieties. Results were reviewed using phase diagrams that were produced and it was found that different mesomorphic characteristics were seen to depend on the mesogenic component as well as lateral and terminal polar groups. In all cases, these mixtures have been determined to have low melting-temperature eutectic compositions, while linear or negative deviation of nematic or smectic isotropic composition temperature dependence was observed.

Physical and Thermal Characterizations of Newly Synthesized Liquid Crystals Based on Benzotrifluoride Moiety

“…Several researchers [ 12 , 14 , 17 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ] have demonstrated that computational studies are a great tool for designing novel materials. Molecular orbital energies, the frontier molecular orbital energy difference, and the molecular geometries of the investigated LC compounds must all be stimulated to produce novel compounds with appropriate optical and thermal properties.…”

“…Due to its high performance and accurate results, density functional theory (DFT) is widely acknowledged as an appropriate instrument for making these predictions [ 39 ]. In addition, one of our research areas focuses on theoretical calculations of molecular geometry that impact thermal properties and links them to experimental data [ 12 , 33 , 40 , 41 ].…”

“…Additionally, the calamitic liquid crystal molecule includes a central linkage part that connects the two (or more) ring systems [1,11]. For systems with a Schiff's base/ester group, Schiff base (-C=N-) is a connecting group connecting the hardcore LCs, and, as recently discovered, the twist-bend smectic mesophases [12,13]. The rigid linear Schiff base bridges maintains the linearity of the structure's core, thereby allowing for the formation of LC phases with extreme stability [14,15].…”