Skoglund Sara, Blomberg Eva, Wallinder Inger Odnevall, Grillo Isabelle, Pedersen Jan Skov, Bergström L Magnus
KTH Royal Institute of Technology, School of Chemical Science and Engineering, Surface and Corrosion Science, SE-100 44 Stockholm, Sweden.
Phys Chem Chem Phys. 2017 Oct 25;19(41):28037-28043. doi: 10.1039/c7cp04662f.
The structural behavior in aqueous mixtures of negatively charged silver nanoparticles (Ag NPs) together with the cationic surfactants cetyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium chloride (DTAC), respectively, has been investigated using SANS and SAXS. From our SANS data analysis we are able to conclude that the surfactants self-assemble into micellar clusters surrounding the Ag NPs. We are able to quantify our results by means of fitting experimental SANS data with a model based on cluster formation of micelles with very good agreement. Based on our experimental results, we propose a novel mechanism for the stabilization of negatively charged Ag NPs in a solution of positively charged surfactants in which cluster formation of micelles in the vicinity of the particles prevents the particles from aggregating. Complementary SAXS and DLS measurements further support this novel way of explaining stabilization of small hydrophilic nanoparticles in surfactant-containing solutions.
分别使用小角中子散射（SANS）和小角X射线散射（SAXS）研究了带负电荷的银纳米颗粒（Ag NPs）与阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）和十二烷基三甲基氯化铵（DTAC）在水性混合物中的结构行为。通过对SANS数据分析，我们能够得出结论：表面活性剂自组装成围绕Ag NPs的胶束簇。我们能够通过将实验SANS数据与基于胶束簇形成的模型进行拟合来量化结果，拟合效果非常好。基于我们的实验结果，我们提出了一种在带正电荷的表面活性剂溶液中稳定带负电荷的Ag NPs的新机制，其中颗粒附近胶束的簇形成可防止颗粒聚集。补充的SAXS和动态光散射（DLS）测量进一步支持了这种解释含表面活性剂溶液中小亲水性纳米颗粒稳定性的新方法。
