Investigation of the role of nanochannels on dynamics of anodic aluminum oxide (AAO) microcantilevers in different gas environments
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2023-01-12
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Abstract
Microcantilevers have made a revolutionary impact in the field of physical, chemical, and biological sensors as the most rudimentary form of MEMS devices. An oscillating microcantilever beam is unique in its versatility to study the effects of flow and gas dynamics at micro/nanoscales. When exposed to various ambient conditions at resonance, its dynamics alter and are typically reflected in frequency, dynamic amplitude, and the Q-factor changes. The physical characteristics of the surface play a crucial role in its dynamics. Anodic aluminum oxide (AAO) shows great potential to be used for microcantilever fabrication due to its inherent, uniform nanoporous surface. The AAO-based microcantilevers provide a low Young`s modulus and a high surface area for the interaction of molecules with the surface, all thanks to their porous surface. This research explores a new AAO platform having nanochannels with both ends of the pores open. The role of nanostructures affecting sensitivity to detect analytes has been exploited to an extent in the past. However, the subtle roles of flow regimes across nanoporous or nanostructured surface modifications remain to be investigated. In the presence of gas flow, the nanoporous surface is expected to induce a non-continuum flow regime. In this study, resonating AAO nano-channeled microcantilevers were used as physical sensors to explore the effect of the non-continuum flow regime on the dynamic properties of the cantilevers. The resonance frequency shifts and quality factor changes of different AAO microcantilevers in different flow rates and gases were investigated, showing a nonlinear trend as the pore diameter increases. More interestingly, the resonance frequency increased with respect to the flow velocity, while more energy dissipated. Also, the dynamic properties of the oscillators were tracked via phase portraits to observe the intricate inter/mutual dependency of displacement and velocity of the oscillating beam at resonance conditions. Keywords: AAO, Nanochannel, gas sensors, phase portraits
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Andalib, D. (2023). Investigation of the role of nanochannels on dynamics of anodic aluminum oxide (AAO) microcantilevers in different gas environments (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.