Molecular Dynamics Simulation of the Structure and Hydroxylation of Silica Glass Surfaces

Authors

  • Jincheng Du,

    1. Center for Glass Research, New York State College of Ceramics, Alfred University, Alfred, New York 14802
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    • *Member, American Ceramic Society.

  • Alastair N. Cormack

    Corresponding author
    1. Center for Glass Research, New York State College of Ceramics, Alfred University, Alfred, New York 14802
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    • *Member, American Ceramic Society.


  • R. E. Youngman—contributing editor

  • Supported by NSF Industry-University Center for Glass Research (CGR), Alfred University.

  • Presented at the ACerS Glass and Optical Materials (GOMD) fall meeting, October 12–15, 2003, Corning, NY.

†Author to whom correspondence should be addressed. e-mail: cormack@ceramics.alfred.edu

Abstract

The surface structure of silica glasses has been simulated using molecular dynamics. The surface hydroxyl concentration was estimated to be 4.5/nm2, based on surface defect statistics. Hydroxyl-silica potentials were developed and used to study the hydroxylation of silica surface. It is found that the energy of chemisorption of water declines in the sequence: three coordinated silicon (Si3) and non-bridging oxygen (NBO) on separate sites, Si3 and NBO on combined sites, two- and three-membered rings. Partial hydroxylation of the most reactive sites, which leads to an OH coverage of 2.5/nm2, was studied. Structural relaxation after hydroxylation was observed.

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