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Surface science is a multidisciplinary subject which affects us on a daily basis. Surfaces are of particular interest because the chemical bonding and atomic structure is different at the surface compared to the bulk properties of a material. This interface is of great significance because it is where charge exchange, or new chemical bonds occur. One essential aspect of surface science is surface wettability, which can be harnessed to produce self-cleaning surfaces. This very lucrative notion, where surfaces with low adhesion to liquids, can result in quick and autonomous shedding, has inspired a multitude of device fabrication and implementation. Over the past decade, several self-cleaning surfaces have been fabricated from superhydrophobic surfaces, which depends on a stable interface between solid, liquid and gas. These surfaces, however, are restricted in their applications and fail to operate upon mechanical damage or nonhomogeneous fabrication processes. Recent advances in wettability science have produced omniphobic lubricant-infused surfaces (OLIS). These surfaces are created by tethering a liquid to a surface, providing a stable liquid interface, which results in excellent aqueous and organic liquid repellency, and high robustness toward physical damage. This thesis will encompass an overview of the classical models for surface wettability, new models for liquid mobility, the criteria required to obtain OLIS, as well as some of the biomedical engineering applications fabricated from this technology. Herein, a novel manufacturing process was developed to produce smooth channeled polymeric microfluidic devices from rough 3D printed molds. Additionally, we integrated OLIS technology with electroconductive sensors to create high surface area electroactive material with self-cleaning properties, ideal to combat non-specific adhesion of biomolecules. Furthermore, our fabrication methods are inexpensive and have the potential to be easily integrated into manufacturing processes to create highly functional microfluidic devices, optimal for lab-on-chip diagnostic platforms. / Thesis / Master of Applied Science (MASc) / Recent advances in wettability science have produced omniphobic lubricant-infused surfaces (OLIS) inspired by the Nepenthes pitcher plant. These surfaces are created by tethering a liquid to a surface, providing a stable liquid interface, which results in excellent aqueous and organic liquid repellency, as well high robustness toward physical damage and high pressure dispensing scenarios. The motivation for this thesis is to expand on the applications for OLIS devices. Herein, a novel manufacturing process was developed to produce smooth channeled polymeric microfluidic devices from rough 3D printed molds. Additionally, we integrated OLIS technology with electroconductive sensors to create high surface area electroactive material with self-cleaning properties, ideal to combat non-specific adhesion of biomolecules.

The goal of this thesis is the development of scalable, low cost synthesis of metal oxide nanostructures based electrodes and to correlate the chemical modifications with their energy conversion performance. Methods in energy conversion in this thesis have focused on two aspects; a potentiometric chemical sensor was used to determine the analytical concentration of some components of the analyte solution such as dopamine, glucose and glutamate molecules. The second aspect is to fabricate a photo-electrochemical (PEC) cell. The biocompatibility, excellent electro-catalytic activities and fast electron transfer kinetics accompanied with a high surface area to volume ratio; are properties of some metal oxide nanostructures that of a potential for their use in energy conversion. Furthermore, metal oxide nanostructures based electrode can effectively be improved by the physical or a chemical modification of electrode surface. Among these metal oxide nanostructures are cobalt oxide (Co3O4), zinc oxide (ZnO), and bismuth-zincvanadate (BiZn2VO6) have all been studied in this thesis. Metal oxide nanostructures based electrodes are fabricated on gold-coated glass substrate by low temperature (< 100 0C) wet chemicalapproach. X-ray diffraction, x-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption and photoluminescence were used to investigate the optical properties of the nanostructures. The resultant modified electrodes were tested for their performance as chemical sensors and for their efficiency in PEC activities. Efficient chemically modified electrodes were demonstrated through doping with organic additives like anionic, nonionic or cationic surfactants. The organic additives are showing a crucial role in the growth process of metal oxide nanocrystals and hence can beused to control the morphology. These organic additives act also as impurities that would significantly change the conductivity of the electrodes. However, no organic compounds dependence was observed to modify the crystallographic structure. The findings in this thesis indicate the importance of the use of controlled nanostructures morphology for developing efficient functional materials.

<p>Energy storage devices have become an integral part of the digital infrastructure of the 21st century. Li-ion batteries are a widely used chemical form of energy storage devices comprising components with varied chemical, mechanical and electrochemical properties. Over long-term usage, the anode and cathode experience spatially heterogeneous Li reaction, mechanical degradation, and reversible capacity loss. The small particle size and environmental sensitivity of materials used in Li-ion battery materials make investigating electrodes' electrochemical and mechanical properties an arduous task. Nevertheless, understanding the effect of electrochemical fatigue load (during the battery's charging and discharging process) on composite electrodes' mechanical stability is imperative to design and manufacture long-lasting energy storage devices.</p><p>Due to the low-symmetry lattice, Lithium Nickel Manganese Cobalt Oxide (NMC) cathode materials exhibit direction-dependent (anisotropic) mechanical properties. In this Dissertation, we first measure the anisotropic elastic stiffness of NMC cathode material using nano-indentation. We also determine the effect of Ni stoichiometry on the indentation modulus, hardness, and fracture toughness of NMC materials. The complete information on the mechanical properties of cathode materials will enable accurate computational results and the design of robust cathodes.</p><p>Further, using operando optical experiments, we report that NMC porous composite cathode experiences asynchronous reactions only during the 1st charging process. Non-uniform carbon binder network coverage across the cathode and Li concentration-dependent material properties of NMC results in the initial asynchronous phenomenon. The information on the degree of electrochemical conditioning of Li-ion battery cathode obtained from optical microscopy can test the consistency of product quality in the industrial manufacturing process. We also investigate the effects of non-uniform reactions on active material’s local morphology change and study the evolution of particle network over long-term cycling. Reported data from experiments depicts that in the early cycles, individual particles’ characteristics significantly influence the degree of damage across the cathode.</p><p>However, the interaction with neighboring particles becomes more influential in later cycles. Computational modeling uses a multiphysics-based theoretical framework to explain the interplay between electrochemical activity and mechanical damage. The methodology, theoretical framework, and experimental procedure detailed here will enable the design of efficient composite electrodes for long-lasting batteries.</p>