Generalization of Kelvin's equation for compressible liquids in nanoconfinement

The Kelvin equation for a compressible liquid in nanoconfinement is written in a form that takes into account not only Laplace's pressure, but also the oscillatory compression pressure. This leads to a simple analytical equation for pressure in nanocapillaries. The corrected equation is used to analyze properties of aqueous systems, including the oscillatory structural forces between attractive surfaces and inert surfaces, repulsive hydration forces between hydrophilic surfaces, and attractive hydrophobic forces between hydrophobic surfaces. Relative vapor pressure in a nanocapillary also is discussed. (c) 2006 Elsevier Inc. All rights reserved.