Long-range attraction between colloidal spheres at the air-water interface: the consequence of an irregular meniscus
Long-range attraction between colloidal spheres at the air-water interface: the consequence of an irregular meniscus
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DOI：
10.1103/physreve.62.5263
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发表时间：
2000-10
期刊：
影响因子：
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通讯作者：
Dimitris Stamou;Claus Duschl;D. Johannsmann
中科院分区：
文献类型：
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作者：
Dimitris Stamou;Claus Duschl;D. Johannsmann
最近的观察带电胶体粒子捕获在空气-水界面揭示了长程粒子间的吸引力，不占标准理论的胶体相互作用。我们提出了一种吸引力的机制，这是基于不均匀的润湿造成不规则形状的颗粒弯月面。当两个相邻的颗粒呈现最佳的相对取向和距离时，由这些扭曲产生的多余的水表面积可以被最小化。典型地，对于在2 m的颗粒间距离处直径为1 m的球体，与理想接触线的小至50 nm的偏差导致10（4）kT数量级的相互作用能。粗糙度引起的毛细现象解释了实验结果，包括通过向亚相中加入洗涤剂引起的簇溶解和线性聚集体的形成。这种相互作用在颗粒稳定的泡沫和乳液中也应该是重要的。
Recent observations of charged colloidal particles trapped at the air-water interface revealed long-range interparticle attractive forces, not accounted for by the standard theories of colloidal interactions. We propose a mechanism for attraction which is based on nonuniform wetting causing an irregular shape of the particle meniscus. The excess water surface area created by these distortions can be minimized when two adjacent particles assume an optimum relative orientation and distance. Typically, for spheres with diameter of 1 m at an interparticle distance of 2 m, deviations from the ideal contact line by as little as 50 nm result in an interaction energy of the order of 10(4)kT. Roughness-induced capillarity explains the experimental findings, including the cluster dissolution caused by addition of detergent to the subphase and the formation of linear aggregates. This kind of interaction should also be of importance in particle-stabilized foams and emulsions.