Thesis
Study of wrinkle structures formed on PDMS fibers
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/100404
Abstract
In recent years, wrinkle structures have been used in many applications, such as sensors, transistors, photomasks and stretchable electronics. The common periodically wrinkled devices are usually fabricated on a piece of solid planar polymer which has good stretch abilities, for example, polydimethylsiloxane (PDMS). In order to form the wrinkle structure, a stiff thin layer with higher Young’s modulus needs to be created on a soft substrate under pre-strain. There are two common methods to generate the stiff layer. The first method is sputter coating of a metal on the soft substrate and the second method is to transform a thin layer of soft substrate into a harder material by chemical or photochemical reaction. In this work, instead of planar substrates, we created the periodic wrinkle structures on PDMS cylindrical fibers which can be used as optical stress sensors. Wrinkles were formed by UV/ozone treatment which resulted in the study of the pre-strain ratio and UV exposure time on the wrinkle wavelength and amplitude. It was found that under the same UV exposure time, wrinkle wavelength decreased as the pre-strain ratio increased. For the same pre-strain ratio, the wrinkle wavelength increased with increasing UV exposure time. Further, the wrinkle wavelength created on the PDMS fibers was found as a function of the fiber diameter. Control experiments performed on thin planar PDMS substrates showed an increase in wrinkle amplitude and wavelength as a function of the substrate thickness too. This work has established experimental and analytical studies of wrinkles wavelength and amplitude, as well as the controllable manufacturing parameters, such as pre-strain ratio, UV exposure time and diameter of the substrates. All these characteristics are described in a set of modified analytical equations. The following text describes how the manufacturing parameters have significant influence in wrinkles wavelength and amplitude.
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Details
- Title
- Study of wrinkle structures formed on PDMS fibers
- Creators
- Jian Geng
- Contributors
- Lei Li (Chair)MICHAEL R. KESSLER (Committee Member)RAHUL P PANAT (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 77
- Identifiers
- 99900525096401842
- Language
- English
- Resource Type
- Thesis