Abstract:

In this paper, the physical and chemical properties of micelle formation process of surfactants were studied by studying the influence of temperature and salt concentration on the critical micelle concentration (CMC) of sodium dodecyl sulfate (SDS) using conductivity method. The thermodynamic parameters of micelle formation were obtained according to the pseudo-phase separation model, and the conductance activation energy of the system dependence of temperature and SDS concentration was discussed. The results showed that CMC of SDS was increased with the increasing of temperature, and decreased with the increasing of sodium chloride concentration, suggesting a spontaneous, exothermic and entropy-increasing process in the micelle formation of SDS in aqueous solution; in kinetics, the relationship between the conductivity of the SDS solution and the temperature conforms to the Arrhenius formula, the activation energy information can reveal the mechanism of ionic surfactants forming micelles.

Key words: Surfactant, Critical micelle concentration, Quasi-phase separation model, Thermodynamics, Activation energy