Kelvin equation capillary rise

Pore radii and pore volume distributions can be calculated on the basis of the classical Kelvin equation which can be adapted to various pore shapes. For t materials the corrected Kelvin equation according to Broekhoff and de Boer leads to better quantitative results. The Broekhoff-de Boer theory also explains why stable adsorption on the inner walls of pores is possible up to a certain critical thickness of the adsorbed layer, without giving rise to immediate capillary condensation of the gas. 

Although the Kelvin equation (3) has been confirmed i for small water drops by the Millikan method ( 2.VII F), the results with other liquids are very puzzling and have not been satisfactorily explained they seem to indicate a value of or about 100 times that for a flat surface, but. this seems likely to be due to experimental errors. The effect of electric charge on the drops seems improbable, since Shereshefsky found a similar result with capillary tubes. Cohan and Mayer, with capillaries of 2 radius, giving a rise of 255 cm., found, however, that both a and density were normal for water and toluene. 

Nearly all of the analysis of mesoporosity starts with the Kelvin-Cohan [14] formulation. Foster [15] proposed the Kelvin equation for the effect of vapor pressure on capillary rise but did not anticipate its use for very small capillaries where the adsorbate thickness is a significant geometrical perturbation. Cohan formulation subtracts the adsorbate film thickness from the radius of the pore to yield the modified Kelvin equation... 

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