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Author ORCID Identifier

https://orcid.org/0000-0003-2975-364X

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2023

Month Degree Awarded

February

First Advisor

Laura C. Bradley

Second Advisor

Alfred J. Crosby

Subject Categories

Materials Science and Engineering | Polymer and Organic Materials | Polymer Chemistry

Abstract

Initiated chemical vapor deposition is used to grow polymer films on substrates of various three-dimensional shapes which exhibit wrinkling during film growth, termed self-wrinkling. Self-wrinkling avoids separate film growth and compression steps and more-closely mimics processes observed in nature. The self-wrinkling process is elucidated on flat elastic substrates, revealing control over the amount of compressive stress by changing deposition conditions. Next, a study of films grown on liquid substrates with interface profiles that either resemble cylinders or contain repeating concave cones, saddles, and bowls affirms the principle that the wrinkle roundness increases with interface curvature. The selection of high versus low stress generating conditions allows for the choice of the wrinkle pattern to be directed by either the stress concentration at boundaries or the substrate curvature. Experiments confirm the observation from simulations by other authors that on the inside of a torus, the lowest energy ridge wrinkle state is oriented around the major axis. The ability to control the character of wrinkle patterns via changes to the local and global substrate shape provides a route to generate materials with contrived surface topography. Next, an interaction between the growing film and substrate was harnessed to create surfaces with dual-scale labyrinth wrinkles. Small wrinkles form from a composite film-substrate skin layer, and large wrinkles form from a growing homopolymer film. The process affords engineers the ability to independently control the two wavelengths. In concert, the results presented in this dissertation provide roadmaps to generate a wide range of wrinkle shapes and understand how to harness and control compressive stress generation in polymer films grown by chemical vapor deposition.

DOI

https://doi.org/10.7275/31944518

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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