Be it the bacterial/viral settlement on doorknobs or the adhesion of ice on car windshields, the unwanted attachment of solid contaminants on surfaces in our environment can present a significant economic and societal burden. Surfaces that are able to resist or shed solids can find applications in the de-icing of airplane wings, preventing marine fouling of ship hulls, eradicating bacterial and viral contamination within hospitals, controlling wax and asphaltene accumulation within crude oil pipelines, and inhibiting scale and frost formation on heat exchanger surfaces. These endless applications encompass foulants which can possess a wide range of moduli (few Pa to few GPa), length scales (few nm2 to several m2) and modes of adhesion. In this work, surface design strategies against a broad range of inorganic and biological foulants will be discussed including ice, frost, snow, Gram-positive and Gram-negative bacteria, and SARS-CoV-2 (the virus responsible for the ongoing COVID-19 pandemic). Performance over application areas ranging from a few μm2 to several m2 will be displayed with a focus on application-oriented testing, scalability and longevity.
This work introduces ice as a model foulant and discuss strategies to minimize the forces required to release ice from different surfaces. In Chapter 2, a novel class of de-icing materials are introduced that exhibit a low interfacial toughness (LIT) with ice, resulting in systems for which the forces required to remove large areas of ice (a few square centimeters or greater) are both low and independent of the iced area. Chapter 3 further shows that these LIT coatings can be used to facilitate shedding of snow, a foulant which can possess a wide range of physical properties. Chapter 4 then transitions into controlling the nucleation and growth of ice/frost on a surface introducing a new class of surfaces that is both anti-icing and icephobic. Chapter 5 introduces the world of biological fouling where we describe a new class of solid surfaces based on naturally occurring antimicrobial molecules which are capable of rapid disinfection (>3-log reduction within few minutes) of a variety of current and emerging pathogens while maintaining persistent efficacy over several months and under extreme environmental duress. We show that these surfaces possess broad spectrum antimicrobial efficacy against E. coli, MRSA, P. aeruginosa and SARS-CoV-2, concluding with their application in burn wound dressings, in vitro and in vivo. Overall, this work highlights the design of state-of-the-art surfaces at the forefront of their field and dives into their performance under different application environments. These patented surfaces have already attracted interest in industry for various residential, transportation, healthcare, renewable energy, military and naval applications.PHDMacromolecular Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169866/1/adhyani_1.pd
