title: 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 ρ(𝐫) and local compressibility χ(𝐫) of a simple liquidsolvent 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 χ(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 χ(𝐫) exhibits a 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.
authors.affiliation: Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom.
authors.forename: Blesson
authors.initials: B
authors.lastname: Chacko
authors.affiliation: H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom.
authors.forename: Robert
authors.identifier: 0000000261432160
authors.initials: R
authors.lastname: Evans
authors.affiliation: Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom.
authors.forename: Andrew J
authors.identifier: 0000000247062204
authors.initials: AJ
authors.lastname: Archer