title: Postsynthesis stabilization of free-standing mesoporous silica films.
abstract: Mixed ammonia-water vapor postsynthesis treatment provides a simple and convenient method for stabilizing mesostructured silica films. X-ray diffraction, transmission electron microscopy, nitrogen adsorption/desorption, and solid-state NMR (13C, 29Si) were applied to study the effects of mixed ammonia-water vapor at 90 degrees C on the mesostructure of the films. An increased cross-linking of the silica network was observed. Subsequent calcination of the silica films was seen to cause a bimodal pore-size distribution, with an accompanying increase in the volume and surface area ratios of the primary (d = 3 nm) to secondary (d = 5-30 nm) pores. Additionally, mixed ammonia-water treatment was observed to cause a narrowing of the primary pore-size distribution. These findings have implications for thin film based applications and devices, such as sensors, membranes, or surfaces for heterogeneous catalysis.
authors.affiliation: Department of Chemistry & Centre for Nanotechnology and Biomaterials, The University of Queensland, Qld 4072, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Vogel
authors.forename: C
authors.initials: C
authors.lastname: Dobe
authors.forename: A
authors.initials: A
authors.lastname: Whittaker
authors.forename: G
authors.initials: G
authors.lastname: Edwards
authors.forename: J D
authors.initials: JD
authors.lastname: Riches
authors.forename: M
authors.initials: M
authors.lastname: Harvey
authors.forename: M
authors.initials: M
authors.lastname: Trau
authors.forename: P
authors.initials: P
authors.lastname: Meredith
mesh_terms: D000327:Adsorption; D000641:Ammonia / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission / Q000379:methods; D009584:Nitrogen / Q000737:chemistry; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D014867:Water; D012822:Silicon Dioxide; D000641:Ammonia; D009584:Nitrogen