Superhydrophobic Coatings in Marine Applications: Drag Reduction and Corrosion Protection

J. Mead, K. Zheng, J. Zhang, E.K.H. Dodiuk, S. Kenig, C. Barry, H. Sun
University of Massachusetts Lowell,
United States

Keywords: superhydrophobic, corrosion, drag reduction

Summary:

Superhydrophobic surfaces have strong water repellency, with static water contact angles above 150° and sliding angles below 10°. Marine related underwater applications have obtained growing attention because, when immersed underwater, an air layer or air plastron is formed between the external liquid medium and the superhydrophobic surface. This air plastron gives these surfaces unique behaviors, such as drag reduction and corrosion protection. The reduced drag coefficient and corrosion protection from superhydrophobic surfaces could provide higher speeds for amphibious vehicles, increased fuel efficiency, and reduced maintenance costs. In this work, a superhydrophobic coating that can be easily applied to existing surfaces and has good durability was studied for its drag reduction and corrosion protection behavior. Superhydrophobic coatings with different topographies were fabricated using a silica filler and a polymer binder by spray coating steel surfaces. The topography was characterized using a variety of surface analysis such as scanning electron microscopy, laser confocal microscopy, and fluorescent microscopy. The effect of processing on the topography was related to the corrosion protection and drag reduction behavior.