Charged hydrophobic colloids at an oil/aqueous phase interface

Abstract

Hydrophobic PMMA colloidal particles, when dispersed in oil with a relatively high dielectric constant, can become highly charged. In the presence of an interface with a conducting aqueous phase, image charge effects lead to strong binding of colloidal particles to the interface, even though the particles are wetted very little by the aqueous phase. In this paper, we study both the behavior of individual colloidal particles as they approach the interface, and the interactions between particles that are already interfacially bound. We demonstrate that using particles which are minimally wetted by the aqueous phase allows us to isolate and study those interactions which are due solely to charging of the particle surface in oil. Finally, we show that these interactions can be understood by a simple image-charge model in which the particle charge $q$ is the sole fitting parameter.

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• Strong scaling of general-purpose molecular dynamics simulations on GPUs
• Characterizing and tracking single colloidal particles with video holographic microscopy
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Cited by in corpus (2)

• Phase behavior of charged colloids at a fluid interface
• Under-liquid Self-Assembly of Submerged Buoyant Polymer Particles