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Lateral capillary interactions between colloids beneath an oil-water interface that are driven by out-of-plane
Bum Jun Park1, Mina Lee1, Bomsock Lee1
1Department of Chemical Engineering, Kyung Hee University, Yongin, 17104, South Korea. bjpark@khu.ac.kr.
Abstract:
We study the lateral capillary interactions between colloids beneath an oil-water interface that lead to closely packed two-dimensional self-assembled colloidal crystals. These capillary forces are caused by the overlap of deformed interfaces above colloids on a solid substrate. The interface deformation is due to the electrostatic disjoining pressure between the charged particles and the charged oil-water interface. It is notable that the short-range (i.e., on the nanometer scale) and out-of-plane electrostatic double-layer interactions, which occur through an aqueous phase, can generate the long-range lateral capillary attraction (i.e., on the micrometer scale).
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