Conductance and 1H NMR Studies of Some Aqueous Surfactants + Fructose Solutions

Abstract

Specific conductivity values of sodium dodecyl sulphate and dodecyl trimethyl ammonium bromide in water and fructose + water measured at 298, 308 and 318 K have been reported. From the observed conductance data the critical micelle concentration and surfactant counter ion association constant (α) values have been obtained. The thermodynamic properties of micellization i.e., ΔGºmic, ΔHºmic and ΔSºmic were calculated using the critical micelle concentration values for sodium dodecyl sulphate + water + fructose and dodecyl trimethyl ammonium bromide + water + fructose systems. The process of micellization of the studied systems is favoured both energetically as well as by entropy gain. ¹H NMR data of the studied systems suggest that solubilization of fructose in aqueous dodecyl trimethyl ammonium bromide micellar solutions occurs neither within micellar core nor at interface but in the bulk, while solubilization of fructose in aqueous sodium dodecyl sulphate micellar solutions occur in the vicinity of micellar surface.