Solid and liquid repellent coatings for universal fouling prevention

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Bolstering the efficiency of renewable energy sources in a major global challenge. A dust-covered solar cell, a wind turbine locked by ice, or a hydroelectric dam clogged by marine foulants all suffer from interfacial adherents that drastically reduce performance. One strategy for preventing the buildup of fouling substances is the use of anti-fouling coatings that effectively resist the adhesion of a given foulant. However, the efficacy of current repellent systems is limited, and no available technologies are capable of preventing a wide range of different fouling substances. Materials whose repellency is generalizable to many different foulants, including various solids, liquids, and organisms, would be highly desirable, but improvements in the fundamental understanding of fouling are needed for their development. In recent years, novel properties have been developed that effectively prevent the adhesion of specific foulants via interfacial polymer mechanics. These developments have yet to be incorporated into models of adhesion, and more work is needed to understand how these new interfacial phenomenon interact with one another, and how effective they are at repelling multiple types of foulants concomitantly.This research program will develop new, fundamental knowledge elucidating how foulants adhere to surfaces, and how this adhesion can be prevented in a rational, unified manner via polymer mechanics. To understand fouling in general, specific foulant systems will be investigated, including ice, barnacles, plastics (during 3D printing), molten metals (during casting), and dried mud. Each of these foulants represents at least one engineering application where the accretion of the foulant drastically hinders optimal performance. And for each application, currently a different strategy has been adopted to help mitigate the fouling. For example, ice accretion is typically mitigated by water-repellent coatings, and biofouling is lessened by biocidal paints. Neither solution is effective at repelling the other foulant, but in Arctic waters both biological attachment and ice accumulation are problematic for naval vessels. Rather than approaching fouling myopically, this research program investigates fouling from a general perspective. Instead of surface chemistry, the recent mechanics-based phenomena of interfacial cavitation, interfacial slippage, and interfacial toughness will be utilized to reduce the foulant adhesion. These three properties can all be realized in plasticized polymers, which will serve as a model anti-fouling system for these studies. A generalizable framework that incorporates these new properties will be developed to explain the anti-fouling behavior of plasticized polymers. Using this framework, materials will be developed that can effectively repel several different types of foulants simultaneously.