Simulation study of hysteresis of argon adsorption in a conical pore and a constricted cylindrical pore.

ABSTRACT

We present a detailed simulation study of the hysteresis loop in conical pores and in cylindrical pores with periodic constrictions to understand how the non-uniformity of the pore diameter along the pore axis would affect the hysteresis loop. The shape and size of the loop in the conical pores (with and without closed ends) are modified by the cone angle because of the change in the curvature of the menisci at the pore ends. In periodically constricted cylindrical pores, the shape and size of the hysteresis loop are not significantly altered by the pore length or by the presence of a closed end because condensation and evaporation in this type of pore occur in the individual pore sections. Similar hysteresis loops have been found in experimental studies, suggesting that structures of the type modelled here occur in real materials.