Thermal and Photophysical Studies of Binary Mixtures of Liquid Crystal with Different Geometrical Mesogens

Abstract

Three binary systems were prepared by mixing of two different mesogenic derivatives, homologues, the first is azo/ester, namely 4-alkoxyphenylazo-4′-phenyl-4″-alkoxybenzoates (IIn+m) and the second is Schiff base/ester, namely 4-(arylideneamino)phenyl-4″-alkoxy benzoates (In+m). The two corresponding analogues from both series in the binary mixtures investigated are of the same terminal alkoxy chain length. Mesomorphic properties were investigated by differential scanning calorimetry (DSC) and phases identified by polarized optical microscope (POM). Photophysical studies were investigated by UV spectroscopy connected to a hot stage. Results were discussed based on constructed binary phase diagrams. All mixtures were found to exhibit eutectic compositions, with linear or slightly linear nematic and smectic A stability/composition dependences. Geometrical parameters were predicted applying density functional theory (DFT) calculations. Twist angle (θ), aspect ratio, dipole moment and the polarizability of the individual compounds were discussed and correlated with the experimental results to illustrate the enhanced the mesophase stability and the mesophase range of the mixture at the eutectic composition compared with those of their individual components.

Binary Liquid Crystal Mixtures Based on Schiff Base Derivatives with Oriented Lateral Substituents

“…The binary mixture of liquid crystalline materials could be better constructed for certain applications in many fields, rather than the individual components [34]. Consequently, the investigation of mesomorphic properties of such mixtures is of considerable interest [35][36][37]. These types of mixtures have been shown to achieve liquid crystalline materials of lower melting point [38][39][40].…”

A New Family of Benzo[h]Chromene Based Azo Dye: Synthesis, In-Silico and DFT Studies with In Vitro Antimicrobial and Antiproliferative Assessment

“…The pharmacological and biochemical properties of 4 H -chromenes inspire many researchers to synthesize new compounds featuring different aromatic rings fused to the chromene moiety and obtain more active derivatives, as they are reliant upon the pattern of substitution. Of these aromatic derivatives, azo chromophores have been utilized due to their comprehensive applications in analytical chemistry [ 27 ], pharmaceuticals [ 28 ], food industries [ 29 ], and optics [ 30 , 31 , 32 , 33 ]. Additionally, they have miscellaneous biological activities, such as antibacterial, antifungal, and anti-HIV properties [ 34 ].…”

Induced Phases of New H-bonded Supramolecular Liquid Crystal Complexes; Mesomorphic and Geometrical Estimation

“…Most of the SMHLCs studied are based on the rod-like intermolecular H-bonding [10,[12][13][14][29][30][31] and there is a lot of interest towards the formation of angular supramolecular hydrogen-bonded liquid crystals [9]. On the other hand, the Schiff base and azo moiety are of special interest due to their ability for trans/cis isomerization upon UV light irradiations [7,[32][33][34][35]. In their supramolecular Schiff base/azo -based LCs, via H-bonding interactions, the rigid core is lengthened, and thus induces the mesomorphic behavior that may not occur in the individual components [11,36].…”