When 12:00 PM - 2:30 PM May 03, 2021
Where virtual
Add event to calendar vCal

PhD Dissertation Defense: "Design and applications of surfaces for solid fouling control"

Abhishek Dhyani (Tuteja)

Whether it is 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 solar panels, 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 with 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). Application areas ranging from a few μm2 to several m2 will be displayed with a focus on application-oriented testing, scalability and longevity.

In collaboration with Mechanical Engineering at UM, this work introduces a novel class of de-icing materials 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 cm
2) are both low and independent of the iced area. We further demonstrate that coatings made of such materials allow ice to be shed readily from large areas (~1 square meter) merely by self-weight. We then proceed to show that these LIT coatings can also be used to facilitate shedding of snow, a foulant with a wide range of physical properties. We show this by applying these coatings on 8m2 solar panels and observing field test performance in wintery Alaska over several months. We also discuss strategies in controlling the nucleation and growth of ice/frost on a surface, introducing a new class of surfaces that are both anti- icing and ice shedding.

This work then transitions into the world of biological fouling and introduces the contrast in modern day disinfection between instant and persistent antimicrobials and surfaces. In collaboration with Michigan Medicine, we describe a new class of solid surfaces based on naturally occurring antimicrobial molecules which are capable of rapid disinfection (>3-log reduction within a 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 can be applied to a myriad of substrates and possess broad spectrum antimicrobial efficacy against E. coli, MRSA, P. aeruginosa and SARS-CoV-2. The thesis concludes with the application of these developed surfaces in burn wound dressings, showing orders of magnitude improvement in antimicrobial performance over current infection prevention materials, both 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.