关键词: N-酰基-L-丝氨酸, 胶束, 热力学参数, 表面活性

Abstract: N-Acyl-L-serine based surfactants were synthesized by using L-serine and three kinds of acyl chloride. The chemical structures of the prepared compounds were confirmed by 1H NMR, ESI-MS and elemental analysis. The aggregation behaviors of sodium N-acyl-L-serine in water were investigated by surface tension at temperatures of 298 K, 308 K, 318 K, 328 K, respectively. From these measurements, the critical micelle concentrations(cmc), the surface tension at the cmc(γcmc), saturated adsorption capacity Γmax and the standard thermodynamic parameters of micellization were calculated respectively. In term of the equation of cmc and temperature, the thermodynamic parameters by using phase separation model indicate that the standard Gibbs free energy(ΔGom) of micellization is negative, the absolute value of the standard enthalpy of micellization, ΔHom, is much smaller than the that of TΔSom in the aqueous solution. Temperature-dependant change of the standard enthalpy of micellization shows the micellization process is enthopy-driven. With the temperature increasing, the micellization is enthalpy-entropy compensated.

Key words: N-acryl-L-serine, micelll, thermodynamic parameter, surface activity