Calorimetric studies on the interaction of sugars and polyols with the non-ionic surfactant TRITON-X-100 in aqueous solutions

Abstract

The enthalpies of solution in the micellar state (Δ H s) for the non-ionic surfactant Triton-X-100 in water and aqueous solution of 1-M glucose, sucrose, mannitol and sorbitol were measured at 298.15 K and 308.15 K by a Tronac titration calorimeter. The enthalpy data were used to evaluate the heat capacities for the surfactant in the micellar state (Δ C p,s) at 303.15 K in the systems studied. The heat capacities of transfer for the surfactant in the micellar state (Δ C p,tr) from water to aqueous solutions of sugars and polyols were found to be negative. The value of (Δ C p,tr) for Triton-X-100 in the micellar state was more negative in glucose solution than in sucrose solution because of the relatively greater water-structure-making ability of glucose, whose hydroxyl groups have a better stereochemical compatibility with the structure of water than those of sucrose. Likewise, (Δ C p,tr) for the surfactant micelles is more negative in mannitol than sorbitol solution because of the better fitting of mannitol than sorbitol with the tridymite structure of water.