Interfacial Assembly of Surfactant-Decorated Nanoparticles: On the Rheological Description of a Colloidal 2D Glass

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• 作者：Armando Maestro ; Omkar S. Deshmukh ; Frieder Mugele ; Dominique Langevin
• 刊名：Langmuir
• 出版年：2015
• 出版时间：June 16, 2015
• 年：2015
• 卷：31
• 期：23
• 页码：6289-6297
• 全文大小：562K
• ISSN：1520-5827

文摘

We address the rheology of assemblies of surfactant-decorated silica nanoparticles irreversibly adsorbed at the gas/liquid interface. Positively charged surfactant molecules (such as CTAB) bind to silica nanoparticle surfaces, and the resulting particle鈥搒urfactant complexes adsorb at gas/liquid interfaces. The surfactant molecules control the wettability of such decorated nanoparticles and their adsorption. The interparticle forces can be tuned by changing the surfactant concentration C_s. Increasing C_s, in addition to a decrease of the particles wettability, leads to an increase of the area fraction of particles at the interface. Oscillatory shear measurements (strain- and frequency-sweep) have been performed. Here, we explore the effect of the surfactant concentration C_s. At high enough C_s, the interface is highly packed, and an overall solidlike response is observed, with 2D glass properties.