Properties of patchy colloidal particles close to a surface: a Monte Carlo and density functional study

Abstract

We investigate the behavior of a patchy particle model close to a hard-wall via Monte Carlo simulation and density functional theory (DFT). Two DFT approaches, based on the homogeneous and inhomogeneous versions of Wertheim's first order perturbation theory for the association free energy are used. We evaluate, by simulation and theory, the equilibrium bulk phase diagram of the fluid and analyze the surface properties for two isochores, one of which is close to the liquid side of the gas-liquid coexistence curve. We find that the density profile near the wall crosses over from a typical high-temperature adsorption profile to a low-temperature desorption one, for the isochore close to coexistence. We relate this behavior to the properties of the bulk network liquid and find that the theoretical descriptions are reasonably accurate in this regime. At very low temperatures, however, an almost fully bonded network is formed, and the simulations reveal a second adsorption regime which is not captured by DFT. We trace this failure to the neglect of orientational correlations of the particles, which are found to exhibit surface induced orientational order in this regime.

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Cited by in corpus (14)

• Thermodynamic perturbation theory for associating fluids with small bond angles: Effects of steric hindrance, ring formation and double bonding
• Molecular Theory for Self Assembling Mixtures of Patchy Colloids and Colloids with Spherically Symmetric Attractions: The Single Patch Case
• Nonequilibrium growth of patchy-colloid networks on substrates
• Nonequilibrium adsorption of 2AnB patchy colloids on substrates
• Molecular theory for the phase equilibria and cluster distribution of associating fluids with small bond angles
• Nonequilibrium self-organization of colloidal particles on substrates: adsorption, relaxation, and annealing
• Mixtures of functionalized colloids on substrates
• Kinetic roughening of aggregates of patchy colloids with strong and weak bonds
• Adsorbed films of three-patch colloids: Continuous and discontinuous transitions between thick and thin films
• Bulk structural informations from density functionals for patchy particles
• Temperature (de)activated patchy colloidal particles
• Effective potentials induced by mixtures of patchy and hard co-solutes
• Discontinuous change from thermally- to geometrically- dominated effective interactions in colloidal solutions
• Dynamics of Network Fluids