title: Probing the geometry and interconnectivity of pores in organic aerogels using hyperpolarized 129XE NMR spectroscopy.
abstract: Hyperpolarized (HP) 129Xe NMR was used for the first time to probe the geometry and interconnectivity of pores in RF aerogels and to correlate them with the [resorcinol]/[catalyst] (R/C) ratio. We have demonstrated that HP 129Xe NMR is an ideal method for accurately measuring the volume-to-surface-area (Vg/S) ratios for soft mesoporous materials without using any geometric models. The Vg/S parameter, which is related both to the geometry and the interconnectivity of the porous space, has been found to correlate strongly with the R/C ratio and exhibits an unusually large span: an increase in the R/C ratio from 50 to 500 results in about 5-fold rise in Vg/S. Unlike conventional techniques, HP 129Xe NMR spectroscopy probes the geometry and interconnectivity of the nano- or mesopores in soft materials, providing new insights into the pore structure.
authors.affiliation: Steacie Institute for Molecular Sciences, National Research Council, Ottawa, Ontario, Canada.
authors.forename: I L
authors.initials: IL
authors.lastname: Moudrakovski
authors.forename: L-Q
authors.initials: LQ
authors.lastname: Wang
authors.forename: T
authors.initials: T
authors.lastname: Baumann
authors.forename: J H
authors.initials: JH
authors.lastname: Satcher
authors.forename: G J
authors.initials: GJ
authors.lastname: Exarhos
authors.forename: C I
authors.initials: CI
authors.lastname: Ratcliffe
authors.forename: J A
authors.initials: JA
authors.lastname: Ripmeester