Collective dynamics of colloids at fluid interfaces

Abstract

The evolution of an initially prepared distribution of micron sized colloidal particles, trapped at a fluid interface and under the action of their mutual capillary attraction, is analyzed by using Brownian dynamics simulations. At a separation λ given by the capillary length of typically 1 mm, the distance dependence of this attraction exhibits a crossover from a logarithmic decay, formally analogous to two-dimensional gravity, to an exponential decay. We discuss in detail the adaption of a particle-mesh algorithm, as used in cosmological simulations to study structure formation due to gravitational collapse, to the present colloidal problem. These simulations confirm the predictions, as far as available, of a mean-field theory developed previously for this problem. The evolution is monitored by quantitative characteristics which are particularly sensitive to the formation of highly inhomogeneous structures. Upon increasing λ the dynamics show a smooth transition from the spinodal decomposition expected for a simple fluid with short-ranged attraction to the self-gravitational collapse scenario.

13 pages, 12 figures, revised, matches version accepted for publication in the European Physical Journal E

References in corpus (9)

• Statistical mechanics and dynamics of solvable models with long-range interactions
• Effective capillary interaction of spherical particles at fluid interfaces
• Geometry of surface mediated interactions
• Force balance of particles trapped at fluid interfaces
• Dynamics of colloidal particles with capillary interactions
• Shock waves in capillary collapse of colloids: a model system for two--dimensional screened Newtonian gravity
• Brownian particles with long and short range interactions
• Jeans type analysis of chemotactic collapse
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• Nonequilibrium Statistical Mechanics of Systems with Long-Range Interactions: Ubiquity of Core-Halo Distributions
• Effects of nanoparticles and surfactant on droplets in shear flow
• Structure and Diffusion of Nanoparticle Monolayers Floating at Liquid/Vapor Interfaces: A Molecular Dynamics Study
• Self-assembly of repulsive interfacial particles via collective sinking
• Onset of anomalous diffusion in colloids confined to quasi-monolayers
• Ewald sum for hydrodynamic interactions with periodicity in two dimensions
• Signature of the time-dependent hydrodynamic interactions on the collective diffusion in colloidal monolayers