Hydrophobicity and geometry: Water at curved graphitic-likesurfaces and within model pores in self-assembled monolayers

Abstract

In this work we perform molecular dynamics simulations of water in contact with simple modelhydrophobic surfaces and pores in order to test the role of local geometry on hydrophobicity. Specif-ically, we study different quantities like orientational ordering, density fluctuations and water residencetimes (autocorrelation functions) around graphene sheets, at the exterior of single-walled carbon nano-tubes, at alkane-like self-assembled monolayers (SAMs) and at pores of different sizes carved in suchSAMs. We show that in the case of the convex graphitic-like surfaces, the cuvature does not affect thelocal hydrophobicity. However, significant curvature dependence will be made evident for the concavesurfaces of the pores carved in the SAMs. The geometrically induced dehydration that occurs as the poresize reaches the subnanometric regime might be operative in realistic settings like protein binding siteswhich require water remotion upon ligand binding.