非离子表面活性剂NP-10与DM复配体系中混合胶束的NMR动态研究

Abstract

两种非离子表面活性剂(DM和NP-10)形成了二元复配体系，通过NMR各种技术对其复配体系中不同比例下形成的混合胶束的动态变化(包括胶束的堆积状况，分子间的排列方式、相互作用点及其分子间与分子内作用的变化等)进行了研究。二维NOESY技术证明了两者分子间的空间距离和相互作用力随着NP-10/DM比例的不同而变化，但其相互作用点不变；NMR的扩散系数表明了混合胶束的动力学半径随着NP-10/DM增大而增加，直到NP-10/DM摩尔比为1:6后趋于稳定，表明复配体系的浓度配比不是无限制的；横向弛豫时间T2显示了单体胶束与混合胶束随着各自比例的逐渐增大而朝着相反方向的变化趋势，此现象佐证了分子间作用力与分子内作用力的区别。弛豫时间还表明，当NP-10/DM的摩尔比为1:1/2~1:1时，其分子间的相互作用力开始减小，分子内作用开始起主导作用，暗示了复配体系中的最佳配比和协同效应的变化。 Two kinds of non-ionic surfactant (DM and NP-10) form a binary complex system, and the dynamic changes (including the accumulation of micelles, intermolecular arrangement, interaction point and the variation of inter-molecular as well as the intra-molecular interaction etc.) of the mixed micelles formed in different proportions of the complex system were studied through a variety of NMR techniques. 2D NOESY experiments reveals that the spatial distance and the interaction force between the two molecules vary with the NP-10/DM ratio, but the interaction point does not change; the diffusion coefficient of NMR shows that the dynamic radius of mixed micelles increases with the increase of NP-10/DM, and then tends to be stable until the mole ratio of NP-10/DM is 1:6, indicating that the concentration ratio of the complex system is not unlimited; the transverse re-laxation time T2 shows the tendency of the monomer micelles and the mixed micelles moving in the opposite direction as the increase of respective proportions. This phenomenon proves the dif-ference between the inter-molecular forces and the intra-molecular forces. The relaxation time also shows that when the molar ratio of NP-10/DM is 1: 1/2 ~ 1: 1, the inter-molecular interaction began to decrease, and the intra-molecular interaction began to play a leading role, suggesting that the optimal ratio and the synergistic effect of the complex system.