关键词: 氯化钠, 十二烷基硫酸钠, 热力学参数, 温度, 驱动

Abstract: In order to better study the effects on the physicochemical properties and structural stability of anionic surfactant micelles in different concentrations of NaCl, based on the critical micelle concentrations of anionic surfactant sodium dodecyl sulfate (C₁₂H₂₅SO₄Na) at different temperatures, the surface tension, foam half-life and viscosity of the solution under different concentrations of NaCl and different temperatures were measured and obtained respectively. On this basis, the thermodynamic parameters such as viscosity activation energy, standard entropy change and standard enthalpy change of the solution under NaCl action and their variation laws were obtained through analysis. The results show that the efficiency of sodium dodecyl sulfate in reducding surface tension is controlled by both temperature effect and salt effect. With the increase of temperature, the temperature effect plays an increasingly important role. The surfactant concentration corresponding to the maximum viscosity is the critical micelle concentration at these temperature and NaCl concentration. The effect of C₁₂H₂₅SO₄Na micellization process was gradually transformed from entropy driven to enthalpy driven with the increase of temperature, and the transformation process was more and more advanced with the increase of NaCl concentration. To understand the coupling effects of temperature and NaCl concentration on the physical and chemical properties of C₁₂H₂₅SO₄Na, so as to lay a foundation for further study of its thermodynamic behavior.

Key words: sodium chloride, sodium dodecyl sulfate, thermodynamic parameter, temperature, driven