Institute of Petroleum Engineering, Chemical Engineering Department, University of Tehran, Iran; IOR Research Institute, Tehran, Iran.
Institute of Petroleum Engineering, Chemical Engineering Department, University of Tehran, Iran.
J Colloid Interface Sci. 2019 Jun 1;545:242-250. doi: 10.1016/j.jcis.2019.03.047. Epub 2019 Mar 14.
There is a notable paucity of studies investigating the impact of charged nanoparticles on the interfacial behavior of nonionic surfactants, assuming that the interactions are negligible in the absence of electrostatic forces. Here, we argue about our observations and the existence of a complex interfacial behavior in such systems depending on the type and chemical structure of surfactant. This study set out to investigate the effects of interactions between hydrophilic silica nanoparticles (NP) and non-ionic surfactants on water/heptane dynamic interfacial properties using drop profile analysis tensiometry (PAT). Three surfactants were studied, namely Triton X-100 (significantly soluble in water phase), CDMPO (well soluble in both phases) and SPAN 80 (oil-soluble). The different chemical structures and partition coefficients of the surfactants enabled us to cover possible interactions and differentiate between bulk and interfacial interactions. We observed that hydrophilic silica NPs had a negligible effect on the interfacial behavior of Triton X-100, that they increased the surface activity of CDMPO when both compounds are initially in the aqueous phase. Most interestingly is that the added NPs generated unstable interfacial NP-surfactant complexes and reduced the pseudo-equilibrium interfacial tension of oil-soluble surfactant, Span 80, even though NPs and surfactants were in different bulk phases.
目前,研究 charged nanoparticles 对非离子表面活性剂界面行为影响的研究相当匮乏,因为假设在没有静电力的情况下,相互作用可以忽略不计。在这里,我们根据表面活性剂的类型和化学结构,对我们的观察结果和此类系统中存在的复杂界面行为提出了质疑。本研究旨在使用滴形分析张力计(PAT)研究亲水二氧化硅纳米颗粒(NP)与非离子表面活性剂之间的相互作用对水/庚烷动态界面性质的影响。研究了三种表面活性剂,即 Triton X-100(在水相中显著溶解)、CDMPO(在两相中均易溶解)和 SPAN 80(油溶性)。表面活性剂的不同化学结构和分配系数使我们能够涵盖可能的相互作用,并区分体相和界面相互作用。我们观察到,亲水二氧化硅 NPs 对 Triton X-100 的界面行为几乎没有影响,但当两种化合物最初都在水相时,它们会增加 CDMPO 的表面活性。最有趣的是,即使 NPs 和表面活性剂处于不同的体相,添加的 NPs 也会生成不稳定的界面 NP-表面活性剂复合物,并降低油溶性表面活性剂 Span 80 的拟平衡界面张力。