Using molecular simulations, we have investigated heat transfer across the solid-fluid interface of a silica wafer in contact with water vapor. Our results show that the thermal or Kapitza resistance decreases significantly, as the surface becomes more hydrophilic. This is primarily due to increases in adsorption and absorption at the surface, which enhances the intermolecular collision frequency at the interface. Increasing this frequency also reduces the dependence of thermal transport on variations in the interfacial temperature and pressure. Decreasing the density diminishes the intermolecular collision frequency thus increasing the thermal resistance. (C) 2008 Elsevier B.V. All rights reserved.