Capillary Condensation of Water between Rinsed Mica Surfaces

Abstract

In previous studies of capillary condensation of water between mica surfaces using the surface force apparatus (SFA) it has not been possible to obtain agreement with the Kelvin equation. The condensates in these studies exhibited refractive index values larger than that of bulk water and often deposited residues of involatile material upon evaporation. We report a study of capillary condensation of water between mica surfaces which have been rinsed in dilute acid solution prior to mounting in the SFA. The refractive indices of water condensates between such surfaces are equal to that of bulk water, and no visible deposits of involatile material remain upon evaporation. The equilibrium meniscus curvatures of the condensates agree with theoretical values calculated from the Kelvin equation.