A simple model of adsorption by swelling porous materials: application of a density functional approach

We apply a density functional approach to describe adsorption of fluids by swelling porous materials. We investigate adsorption at supercritical tempe ratures, and discuss possible changes in the phase behaviour of the fluid w hich result from the volume changes of the pores during the adsorption proc ess. In particular, we show that the swelling may cause splitting of the ca pillary condensation hysteresis loop into two branches; the first of them i s connected with the capillary condensation in a 'collapsed' pore and the s econd one is a result of the swelling.