Janus fluid with fixed patch orientations: theory and simulations

Abstract

We study thermophysical properties of a Janus fluid with constrained orientations, using analytical techniques and numerical simulations. The Janus character is modeled by means of a Kern-Frenkel potential where each sphere has one hemisphere of square-well and the other of hard-sphere character. The orientational constraint is enforced by assuming that each hemisphere can only point either North or South with equal probability. The analytical approach hinges on a mapping of the above Janus fluid onto a binary mixture interacting via a "quasi" isotropic potential. The anisotropic nature of the original Kern-Frenkel potential is reflected by the asymmetry in the interactions occurring between the unlike components of the mixture. A rational-function approximation extending the corresponding symmetric case is obtained in the sticky limit, where the square-well becomes infinitely narrow and deep, and allows a fully analytical approach. Notwithstanding the rather drastic approximations in the analytical theory, this is shown to provide a rather precise estimate of the structural and thermodynamical properties of the original Janus fluid.

20 pages, 10 figures; v2: minor changes plus corrections of typos [Eqs. (A6), (A17), and (A26)-(A28)] appearing in the published version

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Cited by in corpus (12)

• Structural and Thermodynamic Properties of Hard-Sphere Fluids
• Phase diagrams of Janus fluids with up-down constrained orientations
• Equation of state of sticky-hard-sphere fluids in the chemical-potential route
• One-dimensional Janus fluids. Exact solution and mapping from the quenched to the annealed system
• One-dimensional fluids with positive potentials
• The moment sum-rules for ionic liquids at criticality
• Monte Carlo simulation of Hard-, Square-Well, and Square-Shoulder Disks in narrow channels
• Supercooled superfluids in Monte Carlo simulations
• From the Liouville to the Smoluchowski equation for a colloidal solute particle in a solvent
• Andersen-Weeks-Chandler perturbation theory and one-component sticky-hard-spheres
• Bethe-lattice calculations for the phase diagram of a two-state Janus gas
• Finite-size effects and thermodynamic limit in one-dimensional Janus fluids