Molecular origins of mechanical properties in hybrid glasses
Abstract/Contents
- Abstract
- Hybrid organic-inorganic glasses are materials wherein organic and inorganic chemical components are intermixed and covalently bound at the molecular scale. This class of materials has great potential to enable and enhance a range of new technologies given their unique properties. To date, hybrid glasses have been used in a diverse range of applications including protective coatings, adhesion promoting films, ultra-low-k dielectrics, and optical waveguides. The successful integration of hybrid glasses requires that they possess sufficient mechanical properties to withstand often harsh processing and operating conditions. This dissertation presents results from several investigations of how molecular structure controls elastic and fracture properties of hybrid glasses. Two major sol-gel derived hybrid glass systems are discussed. The first is oxycarbosilane (OCS) glasses processed from small organosilane precursors. The second system is ZrOx/epoxysilane hybrids. For the OCS glasses, the primary focus of this work was to develop the capability to generate accurate molecular models of these materials and to simulate their mechanical properties using molecular dynamics as well as a novel fracture model that uses the mathematics of graph theory to predict the 3-D cohesive fracture path at the atomic scale. Using these computational tools, the impact of network connectivity on elastic stiffness and cohesive fracture energy has been elucidated. Also, the exceptionally high stiffness of OCS materials processed from 1,3,5-benzene precursors predicted by computational modeling is discussed. For the ZrOx/epoxysilane materials, linear elastic fracture mechanics experiments were done to characterize the fracture resistance of these glasses under monotonic, static, and cyclic loading conditions. The effects of glass composition, substrate composition, and silane crosslinking on the critical fracture energy were investigated. Additionally, plasticity-driven cyclic mechanical fatigue was observed, providing the first evidence of the importance of fatigue phenomena to hybrid glasses.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2010 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Oliver, Mark Stephen |
|---|---|
| Associated with | Stanford University, Department of Materials Science and Engineering |
| Primary advisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Cai, Wei |
| Thesis advisor | Dubois, Geraud |
| Advisor | Cai, Wei |
| Advisor | Dubois, Geraud |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Mark Stephen Oliver. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2010. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2010 by Mark Stephen Oliver
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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