Multi-functional protective coatings for plastics using open-air spray plasma deposition
Abstract/Contents
- Abstract
- Transparent plastics are increasingly important to emerging technologies such as light-weight transportation, flexible electronics, and display technologies. However, due to the low surface hardness, plastics can be easily scratched and degraded which significantly reduce their optical qualities and lifetimes. In this dissertation, I will focus on the development of durable functional protective coatings for plastics and new understandings of their mechanical properties including adhesion, stiffness, and moisture-assisted cracking behavior. I will demonstrate two scalable processing strategies for synthesizing these coatings, namely, spray deposition of sol-gel precursors and open-air plasma deposition. Firstly, I will focus on the processing of an organosilicate-based bilayer coating with unprecedented combination of adhesion and stiffness using open-air spray and plasma depositions. The bilayer coating exhibited a > 90% transparency in the visible wavelengths, 8-fold the adhesion energy and 4-fold the Young's modulus of commercial sol-gel polysiloxane coatings. The coating deposition rate, elastic modulus, hardness and adhesion to poly methyl methacrylate (PMMA) substrates will be discussed and correlated to the molecular structures and chemical compositions of the coatings. Secondly, I will demonstrate the molecular design strategies for engineering coating's deformation rate sensitivity and fracture resistance in a moist environment. With increasing non-hydrolysable organic network connectivity, the mechanical behavior of the coatings can vary from almost perfectly elastic to increasingly viscoelastic in a controlled fashion. The related fracture resistance was also found to be significantly improved. New insights into the fundamental molecular-scale relaxation and cracking mechanisms of the coatings will also be highlighted. Finally, I will describe a novel and versatile dual-source deposition method involving ultrasonic spraying and open-air plasma deposition for making durable multifunctional nanocomposite coatings. Previous work for making nanocomposites focused on incorporating nanoparticles by either in-situ growth in the matrix or by dispersing into the matrix precursor before deposition. However, in this new method, the nanoparticles and coating matrix are independently deposited which eliminate the potential difficulties associated with preparing high mass fraction composites with well-dispersed nanoparticles. The capability of incorporating several different functional nanoparticles into durable coating matrix with good nanoparticle dispersity, uniformity and strong matrix-nanoparticle interfacial interactions will be highlighted. The effect of nanoparticle concentration, size, and film thicknesses on coatings surface morphology, optical properties and mechanical properties will also be discussed.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2019; ©2019 |
| Publication date | 2019; 2019 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Ding, Yichuan |
|---|---|
| Degree supervisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Salleo, Alberto |
| Thesis advisor | Stebbins, Jonathan Farwell |
| Degree committee member | Salleo, Alberto |
| Degree committee member | Stebbins, Jonathan Farwell |
| Associated with | Stanford University, Department of Materials Science and Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Yichuan Ding. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2019. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2019 by Yichuan Ding
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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