Reactions and Interfacial Behaviors of the Water–Amorphous Silica System from Classical and Ab Initio Molecular Dynamics Simulations Metadata

Title

• Main Title Reactions and Interfacial Behaviors of the Water–Amorphous Silica System from Classical and Ab Initio Molecular Dynamics Simulations

Creator

• Author: Rimsza, Jessica M.
  Creator Type: Personal

Contributor

• Chair: Du, Jincheng
  Contributor Type: Personal
  Contributor Info: Major Professor
• Committee Member: Reidy, Richard F., 1960-
  Contributor Type: Personal
• Committee Member: Shepherd, Nigel Dexter
  Contributor Type: Personal
• Committee Member: Xia, Zhenhai, 1963-
  Contributor Type: Personal
• Committee Member: Brostow, Witold, 1934-
  Contributor Type: Personal

Publisher

• Name: University of North Texas
  Place of Publication: Denton, Texas
  Additional Info: www.unt.edu

Date

• Creation: 2016-05

Language

• English

Description

• Content Description: Due to the wide application of silica based systems ranging from microelectronics to nuclear waste disposal, detailed knowledge of water-silica interactions plays an important role in understanding fundamental processes, such as glass corrosion and the long term reliability of devices. In this dissertation, atomistic computer simulation methods have been used to explore and identify the mechanisms of water-silica reactions and the detailed processes that control the properties of the water-silica interfaces due to their ability to provide atomic level details of the structure and reaction pathways. The main challenges of the amorphous nature of the silica based systems and nano-porosity of the structures were overcome by a combination of simulation methodologies based on classical molecular dynamics (MD) simulations with Reactive Force Field (ReaxFF) and density functional theory (DFT) based ab initio MD simulations. Through the development of nanoporous amorphous silica structure models, the interactions between water and the complex unhydroxylated internal surfaces identified the unusual stability of strained siloxane bonds in high energy ring structure defects, as well as the hydroxylation reaction kinetics, which suggests the difficulty in using DFT methods to simulate Si-O bond breakage with reasonable efficiency. Another important problem addressed is the development of silica gel structures and their interfaces, which is considered to control the long term residual dissolution rate in borosilicate glasses. Through application of the ReaxFF classical MD potential, silica gel structures which mimic the development of interfacial layers during silica dissolution were created A structural model, consisting of dense silica, silica gel, and bulk water, and the related interfaces was generated, to represent the dissolution gel structure. High temperature evolution of the silica-gel-water (SGW) structure was performed through classical MD simulation of the system, and growth of the gel into the water region occurred, as well as the formation of intermediate range structural features of dense silica. Additionally, hydroxylated silica monomers (SiO4H4) and longer polymerized silica chains were formed in the water region, indicating that glass dissolution is occurring, even at short time frames. The creation of the SGW model provides a framework for a method of identifying how interfacial structures which develop at glass-water interfaces can be incorporated into atomistic models for additional analysis of the dissolution of silicates in water.
• Physical Description: x, 214 pages : illustrations

Subject

• Keyword: dissolution
• Keyword: silica
• Keyword: classical molecular dynamics
• Keyword: simulation
• Keyword: materials science and engineering
• Keyword: reactive force field
• Library of Congress Subject Headings: Silica.
• Library of Congress Subject Headings: Molecular dynamics.
• Library of Congress Subject Headings: Water.
• Library of Congress Subject Headings: Silica gel.

Collection

• Name: UNT Theses and Dissertations
  Code: UNTETD

Institution

• Name: UNT Libraries
  Code: UNT

Rights

• Rights Access: public
• Rights Holder: Rimsza, Jessica M.
• Rights License: copyright
• Rights Statement: Copyright is held by the author, unless otherwise noted. All rights Reserved.

Resource Type

• Thesis or Dissertation

Format

• Text

Identifier

• Accession or Local Control No: submission_155
• Archival Resource Key: ark:/67531/metadc849660

Degree

• Degree Name: Doctor of Philosophy
• Degree Level: Doctoral
• Academic Department: Department of Materials Science and Engineering
• College: College of Engineering
• Degree Discipline: Materials Science and Engineering
• Degree Publication Type: disse
• Degree Grantor: University of North Texas

Note

• Embargo Note: Item would be restricted to campus view only for 5 years. Start date for restriction period is the first day of the month immediately following graduation month: June 1 (May graduation), September 1 (August graduation), or January 1 of following year (December graduation). Embargo expired on 2021-05-01.