Limiting Tensile Strength of Capillary-Condensed Liquids

Abstract

Condensation of vapours into mesoporous adsorbents occurs spontaneously at pressures less than their saturation vapour pressure. The thermophysical properties of the resulting capillary liquids, density, thermal expansivity, isothermal compressibility and heat capacity are similar to those of the corresponding bulk liquid. However, the liquid-vapour interface may be highly curved resulting in a large tension or negative pressure within the capillary liquid. Since the liquid is thermodynamically stable, homogenous nucleation of the vapour phase is suppressed but increasing the tension may eventually lead to its rupture by spinodal decomposition. Conditions under which vapours condense into small pores and the requisite adsorbent properties will be discussed. Experimental results for several vapours and adsorbents will be presented.