The buckling of stiff film on a substrate had been of great interest as this response happen spontaneously and is self-organizing. This provides an unconventional, scalable and easy way to fabrication surfaces with tunable structures from the range of nanometers to micrometers. We optimized a process to fabricate stretchable electrodes by transferring wrinkled gold onto elastomer. We tested their electrochemical sensing functionality through detection of glucose concentration with or without strain. Results showed that the stretchable electrodes provide high sensitivity for the detection of glucose (860 ± 60 µA/mM.cm2), comparable to electrodes before transfer. The current detected was also consistent under strain. Investigation of the resistance indicates that the electrode configuration under strain is important as current running parallel to direction of strain is much more affected under tension. We also developed a fast and facile process to fabricate surfaces that consisted of wrinkles and nanoparticles. Using such surfaces, we tested the omniphobicity effect of hierarchical structures consisting of wrinkles and nanoparticles. Results show that all the fluorinated structured surfaces were hydrophobic, ranging from water contact angle of 125° for wrinkled surfaces to 155° for hierarchical surfaces. The surfaces that were either wrinkled or decorated with nanoparticles were oleophilic with low hexadecane contact angles (~26° and ~55° respectively). The combination of both structures achieved oleophobicity of more than 110°. The effectiveness of nanoparticles for low surface tension liquid were due to its re-entrant like structure. The omniphobic surfaces were also shown to be repellent to blood (>135°), making it a potential material for use medical devices. / Thesis / Master of Applied Science (MASc) / Wrinkling is a phenomenon often seen in real life, such as on the skin of a dried plum or human. It is possible to fabricate such wrinkles through having a stiff thin film adhered to an elastic foundation and compressing the foundation. The wrinkles are useful for fabrication of stretchable electrodes as their structure allows the film to stretch without breaking through unfolding. Here, we fabricated stretchable electrodes by transferring such wrinkled structures onto elastic foundation. These stretchable electrodes are shown to be able to detect the concentration of glucose in solution even when stretched. These electrodes are important for creating wearable devices that can monitor glucose levels or other substance continuously. Wrinkles also work as part of hierarchical structure which are helpful for trapping air beneath droplets of fluids. Here we incorporate wrinkles with nanoparticles which helps to make surfaces repellent to both water and oil. Such a function is important for self-cleaning surfaces and can also be used for patterning of surfaces for selective deposition of fluid.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/24286 |
| Date | January 2018 |
| Creators | Chan, Yuting |
| Contributors | Soleymani, Leyla, Engineering Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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