Abstract
The binary mixture of two non-mesogenic compounds, namely, dodecyl trimethylammonium chloride (DTAC) and ortho-phosphoric acid (H3PO4) exhibits very interesting liquid crystalline smectic phases at large range of concentrations and temperature. The mixture with lower and higher concentrations of DTAC exhibits SmA, SmD, SmB and SmE phases, sequentially when the specimen is cooled from its isotropic phase. Different liquid crystalline phases observed in the mixture were studied using optical microscopic techniques. The temperature variations of optical anisotropy and electrical conductivity have also been discussed. Helfrich potential and elastic moduli have also been estimated in the smectic phase using the Helfrich model.