title: Interaction of single water molecules with silanols in mesoporous silica.
abstract: Deep Inelastic Neutron Scattering measurements of water confined in mesoporous silica have been carried out. The experiment has been performed at room temperature on dry and on hydrated samples in order to investigate the interaction between the protons and the silanol groups of the confining surface. With this aim we could control the hydration of the pores in such a way as to adsorb 3.0 water molecules per nm(2), corresponding to a 1 to 1 ratio with the silanol groups of the surface. DINS measurements directly measure the mean kinetic energy and the momentum distribution of the protons. A detailed analysis of the hydrated sample has been performed in order to separate the contributions of the protons in the system, allowing us to determine the arrangement of water molecules on the silanol groups. We find that the hydrogen bond of the water proton with the oxygen of the silanol group is much stronger than the hydrogen bonds of bulk water.
authors.affiliation: Indiana University Cyclotron Facility, Bloomington, IN 47408-1398, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Pantalei
authors.forename: Roberto
authors.initials: R
authors.lastname: Senesi
authors.forename: Carla
authors.initials: C
authors.lastname: Andreani
authors.forename: Piero
authors.initials: P
authors.lastname: Sozzani
authors.forename: Angiolina
authors.initials: A
authors.lastname: Comotti
authors.forename: Silvia
authors.initials: S
authors.lastname: Bracco
authors.forename: Mario
authors.initials: M
authors.lastname: Beretta
authors.forename: Paul E
authors.initials: PE
authors.lastname: Sokol
authors.forename: George
authors.initials: G
authors.lastname: Reiter
mesh_terms: D015394:Molecular Structure; D016062:Porosity; D011789:Quantum Theory; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D012821:Silanes; D014867:Water; C082343:silanol; D012822:Silicon Dioxide