A new method for the investigation of porous structures using mercury porosimetry

The influence of wetting angle hysteresis on volume hysteresis and retention of mercury in porous solids was considered. Although different explanations are possible (as explained in the paper), the resulting effect for cylindrical pores in the examined sample of active carbon was that the advancing angle θ_A = 162°, and the effective value of the receding angle θ_R = 90°. The rise of the mercury volume (V_m) intruded in the second run after the preceding reduction of pressure (p) to zero corresponds with a formation of spherical caps at the orifice of pores. The dependence of V_m on p in such a case has been called local hysteresis and it has been used to evaluate the true θ_A, the number of pores with a radius corresponding to the pressure of intrusion and their mean length.