Optical and thermal properties of a lyotropic micellar nematic phase

Sreepad²,

Nagappa

2015

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We report the results of our studies on optical and thermal properties of two nonmesogenic compounds namely, dodecyl trimethylammonium chloride (DTAC) and Glacial acetic acid (GAA). The mixture exhibits very interesting schlieren texture of lyotropic micellar nematic phase, SmA and SmG phases, respectively, at different concentrations of DTAC sequentially when the specimen is cooled from its isotropic phase. The order parameter (S) of the lyotropic micellar nematic phase is estimated with the help of temperature dependence of optical anisotropy from the measured values refractive index and density data. The temperature variation of order parameter of the experimental curve is very well fitted with the Mayer-Saupe theoretical curve. Electrical conductivity has been discussed. The formation of above phases has been confirmed by optical and DSC studies.

Section: Conductivity Measurementsmentioning

confidence: 99%

Formation of Lyotropic Micellar Nematic Phase in Binary Mixture of Liquid Crystals

Sreepad²,

Nagappa

2015

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“…There are various tools for studying phase transition in liquid crystal. Optical polarizing microscopy is a standard tool for determining phase transitions in the liquid crystal samples [6,7].…”

Section: Introductionmentioning

confidence: 99%

Induced Polymorphism of Smectic Phases in Binary Mixture of Non-Mesogenic Compounds

Sreepad²,

Nagappa

2015

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We report the results of our studies on the optical and thermal properties of the mixture of sodium dodecyl sulfate (SDS) and orthophosphoric acid (H 3 PO 4 ), which exhibits very interesting induced polymorphic smectic phases such as smectic-A, smectic-D, smectic-B, and smectic-E phases, sequentially when the specimen is cooled from its isotropic liquid phase. Different liquid crystalline phases observed in the mixture were studied using differential scanning calorimetry (DSC), X-ray, and optical microscopic techniques. The temperature variation of optical anisotropy has also been discussed. Helfrich potential and elastic moduli have been estimated in the smectic phase using Helfrich model.

“…An abrupt change of electrical conductivity with temperature relates to the phase behavior of lyotropic and thermotropic systems [20,21]. The temperature variations of electrical conductivity in the present case are as shown in Fig.…”

Section: Conductivity Measurementsmentioning

confidence: 95%

Aggregated Columnar Biphasic Region of Lyotropic Chromonic Liquid Crystalline Phase

Sreepad²,

Raghuram³

et al. 2015

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We report the results of our studies on the optical and thermal properties of binary mixture of compounds viz., abietic acid and ethylene glycol. The mixture shows very interesting co-existent biphasic region of aggregated columnar (C+I) and columnar (C) phases respectively at different concentrations of abietic acid sequentially when the specimen is cooled from its isotropic liquid phase. The temperature variations of optical anisotropy and optical textures have also been discussed.