Effects of temperature, pore dimensions and adsorbate on the transition from pore blocking to cavitation in an ink-bottle pore

• Evolution of hysteresis loop with temperature, pore dimensions and adsorbate.
• Fused hysteresis loop of IUPAC and de Boer types.
• Double maxima in excess isotherms under supercritical conditions.

We have carried out comprehensive GCMC molecular simulations to study the effects of temperature (ranging from sub-critical to supercritical), cavity and neck dimensions, and adsorbate on the transition from pore blocking to cavitation in slit shaped ink-bottle pores. Varying these parameters affects, not only the position and the size of the hysteresis loop, but also its shape, which can change from H1, typical for pore blocking, to H1 or H2 combined with Type C (in the de Boer classification). The combined loops can either be fused loops or appear as two separate loops, one of which is of Type H1 and the other Type C. Another highlight of our simulation study is the double maxima in the adsorption isotherm at a supercritical temperature which results from the sigmoidal shape in the plot of bulk gas density versus pressure and the compression of the adsorbate in the confined space at high pressures.