The characterization of macroporous solids: An overview of the methodology

This paper summarizes the principal aims, content and conclusions of a document recently submitted to IUPAC, as a Technical Report, by the IUPAC Working Group on “Liquid intrusion and alternative methods for the characterization of macroporous materials” and to be published in full in Pure and Applied Chemistry. The initial goal of the group was to list, examine and compare the methods presently used to characterize macroporous structures. In addition to mercury porosimetry, the most popular experimental techniques include the intrusion of various non-wetting and wetting liquids, capillary condensation, liquid permeation, imaging and image analysis. The statistical reconstruction of porous materials and the use of macroporous reference materials are also examined. A particular aim is to evaluate the status of mercury porosimetry, since the use of mercury raises a number of safety and environmental issues. The scope and limitations of each method are examined in the context of the scientific and technological requirements and the applicability of some new and unfamiliar methods is also discussed. Finally, an indication is given of the likely direction of future developments in the methodology of macropore characterization.