Study on optical characterization of TGB and reentrant smectic-A phases in binary mixture of two liquid crystals

In this work, our investigation is to study the optical and thermal properties of the binary mixture of cholesteric and nematic compounds, namely, cholesteryl nonanoate and p-methoxybenzylidene-p-ethylaniline, which exhibits a very interesting liquid crystalline twisted grain boundary (TGB) phase and reentrant smectic-A phase. The chiral liquid crystalline TGB phases and reentrant smectic-A phases have been observed at different concentrations and at different temperatures. The existence of TGB and reentrant smectic-A phases is confirmed by differential scanning calorimetry and optical microscopic studies. The variation of optical anisotropy has been discussed. The helical pitch of the cholesteric phase has also been discussed.     

Nano Molecular Self Assembly in the Formation of Induced Mesomorphism in Mixture of ChCl,DTAC, and EG

The multi-component system of cholesteryl chloride (ChCl), dodecyl trimethylammonium chloride (DTAC), and ethylene glycol (EG) exhibits very interesting liquid crystalline mesophases like cholesteric and SmA, SmC, and SmB phases sequentially when the specimen is cooled from its isotropic phase. These phases have been characterized by employing optical and X-ray studies. Pitch of the cholesteric phase has been calculated and discussed. Variation of pitch from the cholesteric phase to smectic phase is smooth and continuous. The temperature variation of optical anisotropy and electrical-conductivity has also been discussed. It has been found that wherever there is a phase transition, the value of electrical susceptibility changes appreciably.     

Co-Existent Biphasic Region of Nematic and Columnar Smectic Phases in Binary Mixture of Berberine and Alizarin Dye

We report the results of our studies on the optical and thermal properties of binary mixture of two compounds viz., berberine and alizarin dye. The mixture shows a very interesting co-existent biphasic region of nematic N + I and smectic C + I phases, sequentially when the specimen is cooled from its isotropic phase respectively at different concentrations of Alizarin dye in berberine molecule. The temperature variations of optical anisotropy, optical textures, and electrical conductivity have also been discussed. Aggregated molecular size has been confirmed by X-ray studies.     

Chromonic liquid crystalline phase transition involving a biphasic region of nematic and hexagonal phases

We report the results of our studies on the optical and thermal properties of binary mixture of two compounds viz. abietic acid and poly ethylene glycol (PEG). The mixture shows a very interesting co-existent biphasic region of lyotropic nematic (N + I) and intermediate hexagonal (M + I) phases, sequentially when the specimen is cooled from its isotropic phase at different concentrations of abietic acid in PEG. The aggregated molecular size has been confirmed by X-ray studies. The temperature variation of optical anisotropy, electrical conductivity, ultrasonic velocity, and molar and adiabatic compressibility has also been discussed.     

Phase diagram involving the mesomorphic behavior of binary mixture of sodium oleate and orthophosphoric acid

The present investigation deals with the binary mixture of two non-mesogenic compounds, viz. sodium oleate (Naol) and orthophosphoric acid (H₃PO₄) which exhibits very interesting liquid crystalline smectic phases at large range of concentrations and temperature. The mixtures with concentrations ranging from 10% to 90% Naol in H₃PO₄ exhibit SmA, SmC, SmE and SmB phases, sequentially when the specimen is cooled from its isotropic phase. Physical properties, such as ultrasonic velocity, adiabatic compressibility and molar compressibility, show anomalous behavior at the isotropic to mesosphase transition.     

Effect of Sulfonation on the Crystallization Behaviour of Syndiotactic Polystyrene

Syndiotactic Polystyrene (sPS) was sulfonated to different levels in a mixture of 1,1,2–trichloroethane and chloroform. Sulfonation levels were determined by nonaqueous titrations using phenolphthalein indicator. Thermal properties of sulfonated sPS (SsPS) ionomers depend on the sulfonation level. Incorporation of sulfonic acid groups in to the syndiotactic polystyrene backbone was found to affect the crystallization behavior of sPS. DSC data indicated that the melting temperature (T_m), heat of fusion, crystallization temperature (T_c), crystallization rate and degree of crystallization were lowered by the incorporation of sulfonic acid group on the syndiotactic polystyrene backbone. Thermal and FTIR data indicated that the sulfonic groups did not enter into the crystal lattice but remained in the amorphous phase.     

Temperature-dependent Anisotropic Nano-Molecular Orientations of Liquid Crystalline Materials

In the present work, our investigation is to study the optical anisotropic properties of the binary mixture of cyano-benzilidene-p-n-octyl-oxy-aniline (CBOOA), cholesteryl nonanoate (CN), which exhibits a very interesting liquid crystalline Cho-TGB-SmC-SmA-SmB phases sequentially when the specimen cooled from its isotropic phase. These phases have been characterized by using microscopic and optical anisotropic technique. The temperature variations of optical anisotropy and electrical conductivity have been discussed. X-ray studies are supported to calculate the nano-aggregated grain size of the molecules.     

Synthesis,biological screening,in silico study and fingerprint applications of novel 1, 2, 4-triazole derivatives

A series of novel 1,2,4 triazole derivatives were synthesized by treating 4-bromo-2-(4H-1,2,4-triazole-3-yl)aniline (4) with different substituted benzene sulfonyl chlorides 5(a-f) and benzyl bromides 7(a-e) . IR, ¹H-NMR, ¹³C-NMR, and mass analysis confirmed the structures of the newly synthesized compounds. All derivatives were screened for their in vitro antibacterial activity against two bacterial strains viz Escherichia coli and Staphylococcus aureus, antifungal activity against Aspergillus flavus and Candida albicans, anthelmintic activity against Pheretima posthuma and also cytotoxicity activity against MDA-MB 231 and A375 cancer cell lines. It was found that some of the derivatives showed significant antibacterial, antifungal, anthelmintic, and cytotoxic activities when compared to respective standard drugs. Molecular docking studies have assisted the theoretical binding mode of the target molecules. Compounds were also explored for fingerprint application.     

Molecular orientation of lyotropic nematic phase in a mixture of two non-mesogenic compounds

We report the results of our studies on the optical and thermal properties of the mixture of two non-mesogenic compounds, namely, sodium dodecyl sulfate (SDS) and glacial acetic acid (GAA). The mixture exhibits very interesting schlieren texture of lyotropic micellar nematic (N_D) phase, SmA and SmB phases, respectively, at different concentrations of SDS in GAA sequentially when the specimen is cooled from its isotropic phase. The order parameter (S) of the lyotropic micellar nematic (N_D) phase is estimated with the help of temperature dependence of optical anisotropy from the measured values of refractive index and density data. The experimental curve showing the temperature variation of order parameter is very well fitted with the Mayer–Saupe theoretical curve. X-ray studies have also been discussed. The formation of the above phases has been confirmed by optical and differential scanning calorimetry studies.