A Light-Scattering Study of Temperature Effect on Micelle Formation of N-Alkanoyl-N-methylglucamines in Aqueous Solution

The physicochemical properties of N-alkanoyl-N-methylglucamine in aqueous solution have been studied by applying a Debye plot and small-system thermodynamics to an analysis of static light scattering data in the temperature range from 25 to 55 °C. A small minimum was found in a plot of the critical micelle concentration vs. temperature, instead of the monotonously decreasing tendency, as in the case of poly(oxyethylene) alkyl ether. The temperature dependence of the aggregation number of the micelle and the spread of the aggregation number distribution of micelle are both very small. The standard enthalpy change associated with micelle formation varies from positive to negative as the temperature is raised. The micellization of N-alkanoyl-N-methylglucamine surfactants is discussed separately in terms of the respective contributions from the hydrophilic and hydrophobic groups.