title: Adsorption in periodically ordered mesoporous organosilica materials studied by in situ small-angle X-ray scattering and small-angle neutron scattering.
abstract: Modified periodically ordered mesoporous organosilica materials were prepared starting from a recently introduced type of sol-gel precursor, containing both organic moieties and hydrolyzable Si-OR groups. In order to thoroughly characterize the mesoporosity and its accessibility, different probe gases were used in conventional gas adsorption experiments. Furthermore, in situ small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) were applied to study the mesoporosity and the sorption processes, taking advantage of scattering contrast matching conditions. Thereby, the materials were characterized not only by different probe molecules but also at different temperatures (nitrogen at 77 K, dibromomethane at 290 K and perfluoropentane at 276 K). The comparison between the standard and in situ SAXS/SANS adsorption experiments revealed valuable information about the porosity and microstructure of the materials. It is demonstrated that the organic moieties are homogeneously distributed; that is, they do not phase-separate from silica on the nanometer scale.
authors.affiliation: Physical Chemistry Department, University of Giessen, 35392 Giessen, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Mascotto
authors.forename: Dirk
authors.initials: D
authors.lastname: Wallacher
authors.forename: Andreas
authors.initials: A
authors.lastname: Kuschel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Polarz
authors.forename: Gerald A
authors.initials: GA
authors.lastname: Zickler
authors.forename: Andreas
authors.initials: A
authors.lastname: Timmann
authors.forename: Bernd M
authors.initials: BM
authors.lastname: Smarsly