近化学专业“临界胶束浓度测定”综合实验研究

Comprehensive Experimental Study on Determination of the Critical Micelle Concentration of Surfactants in the Near-Chemistry Specialty

针对近化学专业设计了一个物理化学综合实验"用电导法和表面张力法测定阴离子表面活性剂(SDS)溶液的临界胶束浓度(CMC)"。从实验项目选择、实验装置组合、实验条件优化,实验作图等几个方面,进行了综合研究。试验结果表明,由电导率-浓度法作图可得其转折点为9.456×10-3 mol·L-1,相对误差为8.69%;由表面张力-浓度法作图可得转折点约为8.75×10-3 mol·L-1,则相对误差仅为-0.57%。结合阴离子表面活性剂(SAD)溶液文献值8.70×10-3 mol·L-1可知,选择最大气泡压力法,用表面张力-浓度法作图结果更好。

The critical micelle concentration of anionic surfactant （SDS） solution was determined by the method of electrical conductivity and surface tension. The accuracy of the experiment was improved from selection of experimental items, combination of experimental devices, and optimization of experimental conditions. The results show that, for conductivity-concentration method, the CMC is 9.45 6×10-3 mol.L-1, and the relative error is 8.69%;for surface tension-concentration method, the CMC is about 8.75× 10^-3 mol.L-1, and the relative error is -0.57%. Combined with the literature value （8.70×10^-3 mol.L^-1） of anionic surfactant （SAD） solution,it＇s pointed out that the surface tension -concentration method is better.