POROSIMETRY OF FRACTAL SURFACES

Many naturally occurring types of particles are known to have surfaces that can be described by fractal dimensions. Although these results have been obtained almost exclusively from molecular adsorption measurements, mercury porosimetry is another technique that has been used to determine the dimensions of fractal surfaces. In this paper, we first examine and compare two methods for extracting the fractal dimension from the derivative of an intrusion curve; by fitting to a power law and by calculating the local dimension from the derivative. These methods are then applied to simulated inhomogeneous surfaces containing cylindrical pores with radii belonging to a distribution which is a sum of two power law functions. Potentially, the local fractal dimension yields the ratio of the component pore volumes of a mixture, as well as more accurate fractal dimensions. However, this technique is very sensitive to uncertainties in the porosimetry data, as is illustrated by results for two coal samples. © 1993 by Academic Press, Inc.