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Azimi Dijvejin, Zahra

University of British Columbia

Metamaterials are artificially engineered materials with unique properties that are not found in nature. They have potential applications in various fields, and their development has opened up new avenues of research in physics, materials science, and engineering. Here, I designed and fabricated kirigami, a 2D mechanical metamaterial, and microwave sensing metamaterials for applications such as antifouling surfaces and sensors. The combination of the out-of-plane deformation of kirigami structures and the fast, on-demand detection of changes in microwave radiation properties of electrical metamaterials were utilized. This thesis presents two key contributions to the use of metamaterials. First, the development of a suspended kirigami surface, a flexible and deformable mechanical metamaterial that reduces the adhesion strength of various foulants including ice, mud, epoxy adhesive, and wax. Such surfaces can even be applied on complex curved geometries. Second, the investigation of electrical microwave sensors (electrical metamaterials) and their inclusion within coatings that exhibit low interfacial toughness with ice, for smart, hybrid de-icing applications. My work first revealed that both the ice adhesion strength and interfacial toughness of some materials are inversely dependent on temperature. Next, I utilized embedded heaters to modulate the surface temperature and tailor the interface properties of ice on the coating. Moreover, embedded microwave metamaterials were used to detect icing and de-icing accurately, which would help optimize the electrical energy expended during de-icing. Finally, my work explores the combination of electrical and mechanical metamaterials for strain or humidity sensing. Heterogeneous kirigami structures and an array of electrical metamaterials are designed and optimized for strain sensing. The amount of strain applied to the kirigami sheet can be correlated to the response of the electrical metamaterials as they rotate out of plane on the kirigami hinges. I extended this concept for humidity sensing by developing a kirigami structure fabricated from a humidity-absorbing material, nylon 6-6. In this case, the kirigami deforms out-of-plane in response to a humidity difference on the two sides of the kirigami sheet, demonstrating the potential of using metamaterials for humidity sensing applications. Overall, this thesis demonstrates the engineering potential of combined mechanical/electrical metamaterials.

Text

2023-07-12

Attribution 4.0 International

http://hdl.handle.net/2429/85239

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by/4.0/