In contrast variation techniques the interaction between the carbon surface and the fluid phase plays a major role. A relative density function p(q) can be constructed from the ratio of the SAXS response with and without the adsorbed fluid to visualize the pore filling. For n-hexane vapor, the dispersion interaction ensures complete filling of the narrow pores, while larger pores are unpopulated. The value of q at which p(q) vanishes for n-hexane coincides with the critical size of this molecule. For water vapor at 50% relative humidity cluster formation and the degree of filling depend on the extent of oxidation. In the highly oxidized sample, a cooperative mechanism enhances the filling even of larger pores. This is an abstract of a paper presented at the 231th ACS National Meeting (Atlanta, GA 3/26-30/2006).
ASJC Scopus subject areas
- Chemical Engineering(all)