Solvation force for long ranged wall-fluid potentials

Abstract

The solvation force of a simple fluid confined between identical planar walls is studied in two model systems with short ranged fluid-fluid interactions and long ranged wall-fluid potentials decaying as $-A{z}^{-p},z\to \infty$, for various values of $p$. Results for the Ising spins system are obtained in two dimensions at vanishing bulk magnetic field $h=0$ by means of the density-matrix renormalization-group method; results for the truncated Lennard-Jones (LJ) fluid are obtained within the nonlocal density functional theory. At low temperatures the solvation force $f_{solv}$ for the Ising film is repulsive and decays for large wall separations $L$ in the same fashion as the boundary field $f_{solv}\sim L^{-p}$, whereas for temperatures larger than the bulk critical temperature $f_{solv}$ is attractive and the asymptotic decay is $f_{solv}\sim L^{-(p+1)}$. For the LJ fluid system $f_{solv}$ is always repulsive away from the critical region and decays for large $L$ with the the same power law as the wall-fluid potential. We discuss the influence of the critical Casimir effect and of capillary condensation on the behaviour of the solvation force.

48 pages, 12 figures

References in corpus (3)

• Density Matrix Renormalization Group Method for 2D Classical Models
• Effect of Gravity and Confinement on Phase Equilibria: A Density Matrix Renormalization Approach
• Universality of the thermodynamic Casimir effect

Cited by in corpus (16)

• Primitive Model Electrolytes in the Near and Far Field: Decay Lengths from DFT and Simulations
• Critical Casimir forces for Ising films with variable boundary fields
• Interplay of critical Casimir and dispersion forces
• Critical Casimir Effect: Exact Results
• Excess free energy and Casimir forces in systems with long-range interactions of van-der-Waals type: General considerations and exact spherical-model results
• Solvent fluctuations around solvophobic, solvophilic and patchy nanostructures and the accompanying solvent mediated interactions
• Layering Transitions and Solvation Forces in an Asymmetrically Confined Fluid
• The phase behaviour and structure of a fluid confined between competing (solvophobic and solvophilic) walls
• Finite-size effects on the behavior of the susceptibility in van der Waals films under $+,+$ boundary conditions
• Critical Casimir forces for $\mathcal{O}(n)$ systems with long-range interaction in the spherical limit
• Properties of the solvation force of a two-dimensional Ising strip in scaling regimes
• Critical Casimir forces in the presence of random surface fields
• Solute particle near a nanopore: influence of size and surface properties on the solvent-mediated forces
• Solvent-mediated interactions between nanostructures: from water to Lennard-Jones liquid
• Critical and near critical phase behaviour and interplay between the thermodynamic Casimir and van der Waals forces in confined non-polar fluid medium with competing surface and substrate potentials
• Solvation forces in Ising films with long-range boundary fields: density-matrix renormalization-group study