Physico-chemical studies of some surfactants in water and in water + pyridine mixture

Abstract

Surface tension and specific conductance values have been measured for the aqueous solutions of dodecyltrimethylammonium bromide (DTAB) and Triton X-100 in pyridine at 298.15, 308.15 and 318.15 K. The observed data have been utilized to evaluate surface and thermodynamic properties of micellization, adsorption at liquid-air interface and transfer of surfactant from aqueous to mixed solvent (water + pyridine). The observed conductance data have been utilized to evaluate the counter-ion association constant (α) and limiting equivalent conductance (<img src='http://www.niscair.res.in/jinfo/caret.gif' border=0>₀). It has been observed that while in DTAB + water + pyridine system the micellization is favoured both by entropy gain as well as energy effect, in Triton X-100 + water + pyridine system it is favoured by large entropy gain only. The observed data have also been interpreted in terms of intermolecular interactions of various components in solution.