Coating Resistance to Biofouling Inception for Freshwater Vehicles

P. Malm, G. Krishnan, R. Loth, A. Steele, I. Bayer
University of Virginia, US

Keywords: biofluidics, biofouling, coatings, hydrophobicity, turbulent flow, laminar flow


Preventing biofouling in natural bodies of freshwater is important for a wide variety of applications. The relationship between surface properties and antifouling has been the subject of many recent studies, with primary focus on long-term exposure across weeks and months. The current study focuses on short-term exposure and the inception of biofouling, with specific focus on the extension of laminar flow across low-speed freshwater vehicles as a mechanism to reduce drag. Adhered particles cause earlier transition to turbulence with a larger operative surface roughness than a respectively clean coating; eliminating adherence prevents turbulent wake regions from forming behind particles and provides an extension of effective laminar flow. The current study’s novelty is the focus on short-term biofouling elements, as opposed to matured biofilms and long-term macrofouling Polytetrafluoroethylene (Teflon) was chosen for comparison to traditional polyurethane coatings for its hydrophobic properties based on static contact angle. Digital microscopy followed a dynamic freshwater environment to determine if bioparticles adhered with sufficient height (5μm) to cause turbulent trips.