title: Structures of water molecules at solvent/silica interfaces.
abstract: The adsorption of water at solvent/silica interfaces was studied using IR-visible sum frequency generation (SFG) vibrational spectroscopy. We discovered a water layer between toluene and silica with no detectable free OHs. The water layer without free OHs showed resistance against further adsorption of water molecules. This "water-resistant" water surface was very stable at room temperature and did not become a regular water layer with free OH over a period of 12 h in water-saturated toluene. However, this special structure of water was not observed at heptane/silica interfaces, at which free OHs were observed. The study indicates that interactions between solvents and water molecules can significantly change the interfacial water properties.
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yang
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Li
authors.forename: Murray R
authors.initials: MR
authors.lastname: Gray
authors.forename: Keng C
authors.initials: KC
authors.lastname: Chou
mesh_terms: D000327:Adsorption; D015394:Molecular Structure; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D014050:Toluene / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D012997:Solvents; D014867:Water; D014050:Toluene; D012822:Silicon Dioxide