Temperature effects on the hydrophobic force between two graphene-like surfaces in liquid water

Abstract

Water-mediated, effective, long-range interaction between two hydrophobic surfaces immersed in water is of great importance in natural phenomena. We perform the molecular dynamics simulations to investigate the effect of temperature on the attractive force between two graphene-like hydrophobic surfaces in SPC/E water. We systematically calculate the force between two hydrophobic surfaces at different inter-wall separations (d) and subsequently determine the correlation lengths at different temperatures. A significant change in the strength of the attractive hydrophobic force is observed with the variation of temperature. The correlation length of effective hydrophobic force increases on lowering the temperature. We also examine the temperature effects on the behavior of confined water molecules by computing the density and orientational profiles. The analyses of these profiles suggest that the layering of water molecules induced by surfaces decreases with increase in temperature of the system. Critical dewetting distance ( $$\hbox {d}_{c}$$ ), where drying transition phenomenon occurs, shifts to the lower value of d upon cooling. Synopsis: The correlation length of effective hydrophobic force increases on lowering the temperature of the system. Critical de-wetting distance ( $$d_{c}$$ ), where drying transition phenomenon occurs, shifts to lower value of inter-wall separation (d) upon cooling.