Phase behavior of charged colloids at a fluid interface

Abstract

We study the phase behavior of a system of charged colloidal particles that are electrostatically bound to an almost flat interface between two fluids. We show that, despite the fact that our experimental system consists of only $10^3$ - $10^4$ particles, the phase behavior is consistent with the theory of melting due to Kosterlitz, Thouless, Halperin, Nelson and Young (KTHNY). Using spatial and temporal correlations of the bond-orientational order parameter, we classify our samples into solid, isotropic fluid, and hexatic phases. We demonstrate that the topological defect structure we observe in each phase corresponds to the predictions of KTHNY theory. By measuring the dynamic Lindemann parameter, ${\gamma }_L(\tau )$, and the non-Gaussian parameter, ${\alpha }_2(\tau )$, of the displacements of the particles relative to their neighbors, we show that each of the phases displays distinctive dynamical behavior.

References in corpus (7)

• 2D Melting: From Liquid-Hexatic Coexistence to Continuous Transitions
• Glass transitions in two-dimensional suspensions of colloidal ellipsoids
• Fractionalization of Interstitials in Curved Colloidal Crystals
• Computer simulations of two-dimensional melting with dipole-dipole interactions
• Specific heat in two-dimensional melting
• Comparison of 2D melting criteria in a colloidal system
• Charged hydrophobic colloids at an oil/aqueous phase interface

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• Phase coexistence in a monolayer of active particles induced by Marangoni flows
• Exotic Topology in Ordinary Soft Matter
• Charging-driven coarsening and melting of a colloidal nanoparticle monolayer at an ionic liquid-vacuum interface