Water-Barrier Properties of Mixed Bis[trimethoxysilylpropyl]amine and Vinyltriacetoxysilane Films

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• 作者：Yimin Wang ; Erik Watkins ; Jan Ilavsky ; Tammy L. Metroke ; Peng Wang ; Byeongdu Lee ; Dale W. Schaefer
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：June 28, 2007
• 年：2007
• 卷：111
• 期：25
• 页码：7041 - 7051
• 全文大小：3294K
• 年卷期：v.111,no.25(June 28, 2007)
• ISSN：1520-5207

文摘

X-ray and neutron reflectivity were employed to elucidate the morphologies of bis[trimethoxysilylpropyl]amine silane (A) and vinyltriacetoxysilane (V) mixed films on Si wafers at different A/V ratios, and theresponse of these films to saturated water vapor. Due to its insensitivity to chemical composition, X-rayreflectivity was used to assess the film density, whereas neutron reflectivity was used to probe water absorptionand chemical change on exposure to water. NMR was employed to determine the reaction mechanism in neatAV mixtures and stoichiometry of the initial reaction. X-ray reflectivity reveals about 30% void volume inthe films with the least void volume detected near stoichiometry. Grazing incidence small-angle scattering(GISAXS) shows that the void volume is at the molecular level, with no distinct pores. Neutron reflectivityon D₂O-conditioned films shows that silane film is not an effective water barrier with about 30 vol % waterbeing absorbed with only a slight thickness increase. Most water is physically absorbed in the void spacewith the least amount being absorbed near the stoichiometric A/V ratio. The scattering length density of thefilms almost returns to the virgin state after re-dry following D₂O vapor exposure. The film thickness, however,remains at the water-vapor-conditioned state. The slight increase in scattering length density and irreversiblethickness change after re-dry indicate some reaction with water during D₂O conditioning. A D-rich layer isalso observed at the air side surface in D₂O-conditioned films regardless of A/V ratio.