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Full-Text Articles in Engineering
Vapor Deposition Of Self-Wrinkling Polymer Films, Robert N. Enright
Vapor Deposition Of Self-Wrinkling Polymer Films, Robert N. Enright
Doctoral Dissertations
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 …
Post-Wrinkling Behaviors In Layered Elastic Polymers, Anesia D. Auguste
Post-Wrinkling Behaviors In Layered Elastic Polymers, Anesia D. Auguste
Doctoral Dissertations
Surface instabilities include a variety of different modes such as wrinkles, folds, and creases. Such surface instabilities have been used in numerous contexts including changing the wetting, optical, and mechanical properties of different material surfaces for applications in flexible electronics, tissue engineering and biosensors. Interesting surface morphologies can arise due to differences in pre-strain, stiffness, and thickness between the film and substrate; however, the effects of these differences are not well understood. We have developed an experimental system, complemented by finite element simulations, to systematically vary the pre-stretch of the substrate, modulus contrast and thickness contrast to study the transitions …
Effect Of Processing History And Material Properties On The Growth Of Wrinkle Amplitude, Yu-Cheng Chen
Effect Of Processing History And Material Properties On The Growth Of Wrinkle Amplitude, Yu-Cheng Chen
Doctoral Dissertations
Wrinkling has been employed by many organisms to form unique topography, such as fingerprints, gut villi, and surface of flower petal cells. The wavy wrinkle structure provides friction enhancement, surface area increase, optical, and wetting properties improvement. Inspired by Nature, scientists have created wrinkles synthetically and proposed numerous uses for them. However, wrinkling surfaces encounters limitations on achieving massive area and high amplitude-to-wavelength ratio (aspect ratio). The three phase contact line wrinkling technique creates well-defined wrinkles in a continuous fashion, and has great potential to scale-up for massive production. In addition to the velocity dependent adhesion force, we find the …