Toughening materials with polymers in molecular-scale confinement
Abstract/Contents
- Abstract
- This work explores the mechanical and fracture properties of polymers in the extreme limits of molecular confinement, where a stiff inorganic phase confines polymer chains to dimensions far smaller than their bulk radius of gyration. We show that polymers confined at molecular length scales dissipate energy through a novel, confinement-induced toughening mechanism that involves the bridging and pullout of individual polymer chains. This mechanism contrasts with toughening processes in bulk and weakly-confined polymers and describes behavior that cannot be explained by existing entanglement-based theories of polymer deformation and fracture. We support the confined molecular bridging mechanism with a model that quantifies the nanomechanical processes occurring on the length scale of individual polymer chains. We show that the toughening is controlled by the molecular size and the degree of confinement, but is ultimately limited by the strength of individual molecules. This represents a fundamental limit on the ability of polymers to toughen nanocomposite materials. These insights overturn traditional expectations of how the toughness of a composite would change with increasing confinement of a constituent polymer phase. As the length scales of nanoscale devices and nanostructured materials continue to shrink, this unique property of confined polymers can increasingly be used in device and nanocomposite design.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Isaacson, Scott G |
|---|---|
| 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 | Nix, William D |
| Thesis advisor | Salleo, Alberto |
| Advisor | Nix, William D |
| Advisor | Salleo, Alberto |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Scott G. Isaacson. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Scott Gregory Isaacson
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