Binary liquid mixtures in porous solids.

The technique of nuclear magnetic resonance cryoporometry has been used to study the behavior of binary liquid mixtures of water and decane in porous sol-gel silicas. It was observed that the water preferentially adsorbed onto the silica surface and so was able to displace the decane from the pores.

Pore surface exploration by NMR.

A carefully chosen set of experimental techniques applied to porous media characterization provides results that can be much greater than the sum of the individual parts. The inter-relation and complementarity of a number of techniques will be considered. NMR cryoporometry provides a valuable method of pore size measurement. An NMR method that is more widely used to assess pore dimensions relies on relaxation time analysis of a liquid that fills the pores and the enhanced relaxation that occurs in a liquid at the solid/liquid interface. Thermoporometry, a method based on the application of Differential Scanning Calorimetry (DSC), is closely related to cryoporometry, but employs a different set of assumptions to evaluate pore size distributions. Comparison of the results obtained on the same samples using all these methods together with gas adsorption serves to validate the methods and provide significantly more information about surface-fluid interaction and the behavior of nano-scale material within pores than each method employed in isolation. Technique developments will be discussed and applications of these methods to ideal silicas will be used to illustrate their power, particularly in combination.