Generalization of Kelvin's Equation for Compressible Liquids in Nano-Confinement
Yiming Chen, Timothy E. Wetzel, Gregory L. Aranovich, and Marc D. Donohue. Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218
Kelvin's equation for a compressible liquid in nano-confinement 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.