激光散射研究单价盐对C_8-卵磷脂胶团形成的影响

LASER LIGHT SCATTERING STUDIES ON THE EFFECT OF SALTS ON MICELLE FORMATION OF C_8-LECITHIN

用激光散射测量确定C_8-卵磷脂临界胶团浓度及其随温度、盐离子的变化。从中导出了胶团分子量,形成因子,能量梯级间隔以及标准焓等反映该溶液内分子相互作用的重要参量,从而导出单价盐调控胶团大小以至形成和解体的规律和方法。

The critical micelle concentration (CMC) of aqueous C_8-lecithin solutions wasmeasured as a function of temperature, salt type and concentration by laser lightscattering. The CMC's are raised linearly with the concentration of KI, but show abroad maximum in their dependence on the concentration of KCl. As temperatureincreases, the CMC's of all the systems are raised.The negative values of the ladderspacing and standard enthalpy of the micelle formation deduced from the CMC valuesindicate that micelle formation is a spontaneous process. Compared with the salt freesystem,the micelles in the KI added solutions are less likely to form and less stable,while the micelles in the KCl added (≥0.35 mol·L^(-1)) solutions are easier to formand more stable. The average aggregation number of the micelles and the micellegrowth parameter Δμ obtained from the present experiment are quite consistent withthose obtained previously from the coexistence curves.