(330w) Thermoporometric Investigation Of Solvent-Surface Interactions In Nanoporous Inorganic Membranes

Thermoporometry provides a useful tool for characterizing nanoporous materials by relating the freeze/melt behavior of a confined probe liquid, typically water, to the pore size distribution using a relationship analogous to the Gibbs-Thompson equation. Near the pore wall, liquid-surface interactions arising from van der Waals, electrostatic, and structural forces, as well as adsorption, can yield an unfreezable liquid surface film that spans multiple molecular layers. In small nanopores (< 20 nm), the presence of this film reduces the measured pore size of the nanomaterial. In this work, a new technique is described where thermoporometry is used to detect liquid-surface interactions in nanoporous alumina, titania, and zirconia membranes using a host of solvent probe molecules including water, cyclohexane, and 1-octanol (i.e. a polar, an apolar cyclic, and an alkanol molecule, respectively). Particular emphasis is placed on characterizing these interactions and relating them to membrane solvent permeability to determine how surface forces influence fluid transport at the nanoscale.