NP-10与单链、双链季铵盐三种复配体系相互作用规律的NMR研究

Interactions Between NP-10 and Single/Double Chain Quaternary Ammonium Salts Studied by NMR Spectroscopy

通过核磁共振(NMR)技术研究了阳离子表面活性剂,包括单链(DTAC)和双链(C_(12)-C_4-C_(12)和C_(12)-C_8-C_(12))氯化物季铵盐,与非离子表面活性剂壬基酚聚氧乙烯醚(NP-10)组成的3种复配体系的相互作用及作用点、排列方式、混合胶束中分子间与分子内作用的变化规律等.2D NOESY技术证明了这3种复配体系相互作用力大小顺序为NP-10/C_(12)-C_8-C_(12)>NP-10/C_(12)-C_4-C_(12)>NP-10/DTAC,它们的相互作用点相同但作用点数目不同,自扩散系数显示NP-10对混合胶束的动力学半径影响大于季铵盐.弛豫时间表明,当NP-10/DTAC和NP-10/C_(12)-C_s-C_(12)(s=4或8)的混合摩尔比分别为1:3和1:2时,复配体系中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,这暗示它们最佳摩尔配比分别为1:3和1:2,空间距离也佐证了这一结论.

NMR spectroscopy was used to study the behaviors of three binary surfactant micellar solutions, NP-10/DTAC,NP-10/C12-C4-C12 and NP-10/C12-C8-C12 respectively. Relative arrangement and the sites of interactions between the surfactant molecule pairs in the mixed micelles, as well as the differences in inter-/intra- molecular interactions were investigated. 2D NOESY experiments revealed that the number of sites of interaction varied across the different binary mixtures, and the degreeof interactions increased in the following order: NP-10/C12-C8-C12>NP-10/C12-C4-C12>NP-10/DTAC. Self-diffusion coefficientexperiments showed that the influence of NP-10 on the hydro-dynamic radius of the mixed micelles was greater than that ofquaternary ammonium salts. Spin-spin relaxation time experiments indicated that, for NP-10/DTAC and NP-10/C12-Cs-C12 (s =4 or 8) binary systems, intra-molecular interactions dominated and inter-molecular interactions began to decrease at molar ratios 1∶3 and 1∶2. These points corresponded to the optimal molar ratio for synergic effects. Spatial distance measurements supported this result, confirmed that the optimal molar ratio was 1∶3 and 1∶2.