The interaction of anionic silica nanoparticles with nonionic decaethylene glycol mono-dodecyl ether (C12E10) and ionic surfactants [both anionic sodium dodecyl sulfate (SDS) and cationic dodecyl trimethyl ammonium bromide (DTAB)] has been studied by small-angle neutron scattering and dynamic light scattering. The nonionic and cationic surfactant micelles are adsorbed on nanoparticles, whereas no adsorption of SDS surfactant micelles on nanoparticles is observed. The adsorption of C12E10 micelles provides additional steric stability to nanoparticles. However, the adsorption of cationic micelles leads to micelles-mediated fractal aggregation of nanoparticles. In the case of SDS surfactant, nanoparticles and micelles coexist in the solution. Furthermore, the adsorption behavior of surfactant micelles on nanoparticles has been tuned using a combination of nonionic and ionic surfactants. The combination of nonionic C12E10 with anionic SDS makes surfactant micelles to desorb from nanoparticles, whereas the combination of nonionic C12E10 with cationic DTAB leads to fractal aggregation of nanoparticles. The systematic transitions of micelle adsorption to desorption on nanoparticles with a C12E10–SDS mixed surfactant system and the aggregation of nanoparticles in a C12E10–DTAB mixed surfactant system as a function of ionic surfactant (SDS or DTAB) concentration have been examined. The micelles desorption from nanoparticles follows an exponential decay behavior with an increase in SDS concentration in C12E10–SDS, whereas the aggregate size shows an exponential growth with DTAB in C12E10–DTAB. The electrostatic interactions between nanoparticles and surfactant micelles are found to be dominating for tuning these transitions.

中文翻译：

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通过表面活性剂的组合调节纳米颗粒上的胶束吸附

阴离子二氧化硅纳米粒子与非离子十甘醇单十二烷基醚 (C12E10) 和离子表面活性剂 [阴离子十二烷基硫酸钠 (SDS) 和阳离子十二烷基三甲基溴化铵 (DTAB)] 的相互作用已通过小角中子散射和动力学研究光散射。非离子和阳离子表面活性剂胶束吸附在纳米粒子上，而未观察到 SDS 表面活性剂胶束在纳米粒子上的吸附。C12E10 胶束的吸附为纳米颗粒提供了额外的空间稳定性。然而，阳离子胶束的吸附导致纳米粒子的胶束介导的分形聚集。在 SDS 表面活性剂的情况下，纳米颗粒和胶束共存于溶液中。此外，表面活性剂胶束在纳米颗粒上的吸附行为已经使用非离子和离子表面活性剂的组合进行了调整。非离子 C12E10 与阴离子 SDS 的结合使表面活性剂胶束从纳米颗粒上解吸，而非离子 C12E10 与阳离子 DTAB 的结合导致纳米颗粒的分形聚集。研究了在具有 C12E10-SDS 混合表面活性剂系统的纳米颗粒上胶束吸附到解吸的系统转变以及作为离子表面活性剂（SDS 或 DTAB）浓度函数的 C12E10-DTAB 混合表面活性剂系统中纳米颗粒的聚集。随着 C12E10-SDS 中 SDS 浓度的增加，纳米颗粒的胶束解吸遵循指数衰减行为，而聚集体尺寸在 C12E10-DTAB 中随 DTAB 呈指数增长。