title: Pure silica chabazite molecular spring: a structural study on water intrusion-extrusion processes.
abstract: Water intrusion-extrusion isotherms performed at room temperature on hydrophobic pure silica chabazite show that the water-Si-CHA system displays real spring behavior. However, differences in pressure-volume diagrams are observed between the first and the other intrusion-extrusion cycles, indicating that some water molecules interact with the inorganic framework after the first intrusion. (29)Si and especially (1)H solid-state NMR showed the creation of new defect sites upon the intrusion-extrusion of water and the existence of two kinds of water molecules trapped in the supercage of Si-CHA: a first layer of water strongly hydrogen bonded with the silanols of the framework and a subsequent layer of liquidlike physisorbed water molecules undergoing interaction with the first layer. This hydrogen bonding scheme is also supported by X-ray powder diffraction.
authors.affiliation: Laboratoire de Matériaux à Porosité Contrôlée, UMR CNRS 7016, ENSCMu, UHA, 3 rue Alfred Werner, 68093 Mulhouse Cedex, France.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Trzpit
authors.forename: Séverinne
authors.initials: S
authors.lastname: Rigolet
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Paillaud
authors.forename: Claire
authors.initials: C
authors.lastname: Marichal
authors.forename: Michel
authors.initials: M
authors.lastname: Soulard
authors.forename: Joël
authors.initials: J
authors.lastname: Patarin