Park, Simon S.Wong, Danny2018-09-142018-09-142018-09-06http://hdl.handle.net/1880/107731Hydrogen gas is a common byproduct in industrial processes. It is also frequently used in practical applications such as fuel cell vehicles. It has no smell and no taste, but it may pose immediate safety risks because it is combustible in air. It is also un wanted in manufacturing processes as it causes hydrogen-assisted cracking. Sensitive and selective gas sensors are critical to rapidly detect and minimize potential hazards. In this study, we propose a multi-modal hydrogen sensor that combines electrochemical and resonance-based sensing approaches using both quartz tuning forks (QTF) and quartz crystal microbalances (QCM). Near-field electrospinning is used to deposit uniform, semi-conductive nanofibers connecting the two prongs of a QTF. Electrospinning parameters are also optimized on QCM to maximize sensing performance. The most important parameters include polymer concentration, additive concentration and tip-to-collector distance. Treated multi-walled carbon nanotubes (MWCNT), platinum nanoparticles and polyaniline (PANI) are used as the sensing materials with polyethylene oxide (PEO) being used as an electrospinning guide. The effects of intensive pulsed light (IPL) for welding the nanofibers to the platinum coated surfaces are also investigated. The attached sensing materials caused the resonance frequency to shift due to increased stiffness but provided increased surface area for selective adsorption and allowed for electrical impedance changes to be measured. The resonance frequency and electrical impedance both decrease when exposed to hydrogen gas. The sensing methods are combined to develop sensitive gas sensors that are selective to hydrogen compared to a multitude of other gases. Models are developed to back calculate the hydrogen concentration based on the sensor response. The development of these sensors lead to new methods for compact multi-modal sensing.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.hydrogen sensingnear field electrospinningnanofibersquartz tuning forkquartz crystal microbalanceANOVAChemistry--PolymerEngineering--ChemicalMaterials ScienceEngineering--Mechanicalmaster thesis10.11575/PRISM/32907