利用1H NMR探究混合离子型/非离子型表面活性剂临界胶束浓度降低的实质

利用¹H NMR技术研究了离子/非离子表面活性剂形成的二元混合体系，结果显示表面活性剂的混合导致各组分的临界胶束浓度（CMC）均比各自纯溶液有所降低，用吸附平衡理论清楚地解释了这个现象.通过定量分析，发现不同的表面活性剂混合使得其组分CMC降低的程度各异，可以理解为它们吸附于界面单分子吸附层上的分子之间相互作用的不同（相吸或相斥）引起的.由此揭示了"协同效应"的实质，可以为选择适当的表面活性剂类型和混合比例以达到预期的性能提供有力的参考.

Mixing-Induced Decreases in Critical Micelle Concentration in Aqueous Solution of Surfactants:Probing into the Mechanisms with 1H NMR Spectroscopy

As revealed by ¹H NMR experiments, the critical micelle concentration (CMC) of a surfactant in the aqueous solution decreases when a surfactant of different type is mixed in, a phenomenon that has been explained by the adsorption equilibrium theory. It has also been observed that the extents of mixing-induced reduction in CMC values differ among different surfactant types, depending on the interactions (absorption or repulsion) between the adsorbed surfactant molecules and the adsorption mono-layer. The results of ¹H NMR experiments provided a clear picture for the so-called "synergistic effect", and thus might be used to guide the optimization of surfactant mixture formula to achieve desired performance.