Bastiat Guillaume, Grassl Bruno, Borisov Oleg, Lapp Alain, François Jeanne
Laboratoire de Physico-Chimie des Polymères (L.P.C.P.), C.N.R.S./U.P.P.A. UMR 5067, Hélioparc Pau-Pyrenees, 2 Av. du Président Angot, 64053 Pau cedex 9, France.
J Colloid Interface Sci. 2006 Mar 15;295(2):417-26. doi: 10.1016/j.jcis.2005.11.067. Epub 2005 Dec 27.
Mixed micelle of protonated or deuterated sodium dodecyl sulfate (SDS and SDSd25, respectively) and poly(propylene oxide) methacrylate (PPOMA) are studied by small-angle neutron scattering (SANS). In all the cases the scattering curves exhibit a peak whose position changes with the composition of the system. The main parameters which characterize mixed micelles, i.e., aggregation numbers of SDS and PPOMA, geometrical dimensions of the micelles and degree of ionisation are evaluated from the analysis of the SANS curves. The position q(max) of the correlation peak can be related to the average aggregation numbers of SDS-PPOMA and SDSd25-PPOMA mixed micelles. It is found that the aggregation number of SDS decreases upon increasing the weight ratio PPOMA/SDS (or SDSd25). The isotopic combination, which uses the "contrast effect" between the two micellar systems, has allowed us to determine the mixed micelle composition. Finally, the SANS curves were adjusted using the RMSA for the structure factor S(q) of charged spherical particles and the form factor P(q) of spherical core-shell particle. This analysis confirms the particular core-shell structure of the SDS-PPOMA mixed micelle, i.e., a SDS "core" micelle surrounded by the shell formed by PPOMA macromonomers. The structural parameters of mixed micelles obtained from the analysis of the SANS data are in good agreement with those determined previously by conductimetry and fluorescence studies.
通过小角中子散射（SANS）研究了质子化或氘代十二烷基硫酸钠（分别为SDS和SDSd25）与聚甲基丙烯酸环氧丙酯（PPOMA）的混合胶束。在所有情况下，散射曲线都呈现出一个峰值，其位置随体系组成而变化。通过对SANS曲线的分析，评估了表征混合胶束的主要参数，即SDS和PPOMA的聚集数、胶束的几何尺寸以及电离度。相关峰的位置q(max)与SDS-PPOMA和SDSd25-PPOMA混合胶束的平均聚集数有关。研究发现，随着PPOMA/SDS（或SDSd25）重量比的增加，SDS的聚集数会减少。利用两种胶束体系之间的“对比效应”的同位素组合，使我们能够确定混合胶束的组成。最后，使用带电球形颗粒的结构因子S(q)和球形核壳颗粒的形状因子P(q)的RMSA对SANS曲线进行了拟合。该分析证实了SDS-PPOMA混合胶束具有特殊的核壳结构，即由SDS“核心”胶束被PPOMA大分子单体形成的壳层包围。从SANS数据分析获得的混合胶束的结构参数与先前通过电导法和荧光研究确定的参数高度一致。
