Solvent fluctuations around solvophobic, solvophilic and patchy nanostructures and the accompanying solvent mediated interactions

Abstract

Using classical density functional theory (DFT) we calculate the density profile $\rho (\mathbf{r})$ and local compressibility $\chi (\mathbf{r})$ of a simple liquid solvent in which a pair of blocks with (microscopic) rectangular cross-section are immersed. We consider blocks that are solvophobic, solvophilic and also ones that have both solvophobic and solvophilic patches. Large values of $\chi (\mathbf{r})$ correspond to regions in space where the liquid density is fluctuating most strongly. We seek to elucidate how enhanced density fluctuations correlate with the solvent mediated force between the blocks, as the distance between the blocks and the chemical potential of the liquid reservoir vary. For sufficiently solvophobic blocks, at small block separations and small deviations from bulk gas-liquid coexistence, we observe a strongly attractive (near constant) force, stemming from capillary evaporation to form a low density gas-like intrusion between the blocks. The accompanying $\chi (\mathbf{r})$ exhibits structure which reflects the incipient gas-liquid interfaces that develop. We argue that our model system provides a means to understanding the basic physics of solvent mediated interactions between nanostructures, and between objects such as proteins in water, that possess hydrophobic and hydrophilic patches.

arXiv comment19 pages, 21 figures

References in corpus (14)

• The molecular structure of the interface between water and a hydrophobic substrate is liquid-vapor like
• Pathways to dewetting in hydrophobic confinement
• The Local Compressibility of Liquids near Non-Adsorbing Substrates: A Useful Measure of Solvophobicity and Hydrophobicity?
• Thin film evolution equations from (evaporating) dewetting liquid layers to epitaxial growth
• Critical Drying of Liquids
• Quantifying density fluctuations in water at a hydrophobic surface: evidence for critical drying
• Non-analytic curvature contributions to solvation free energies: influence of drying
• Solvent mediated interactions between model colloids and interfaces: A microscopic approach
• Depletion potentials near geometrically structured substrates
• Dynamical density functional theory for the dewetting of evaporating thin films of nanoparticle suspensions exhibiting pattern formation
• Solvent mediated interactions close to fluid-fluid phase separation: microscopic treatment of bridging in a soft core fluid
• Solvation force for long ranged wall-fluid potentials
• The phase behaviour and structure of a fluid confined between competing (solvophobic and solvophilic) walls
• Bridging transitions for spheres and cylinders

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