Applied Surface Science, Vol.345, 36-43, 2015
Hemolymph drop impact outcomes on surfaces with varying wettability
Insect fouling from coagulated hemolymph and exoskeleton parts is a major challenge in the aerospace industry for the next generation of aerodynamic surfaces, which will employ laminar flow that requires extremely smooth surfaces. However, the wetting physics and dynamics of hemolymph (insect blood) on surfaces are not well understood. The present study seeks to gain a fundamental insight on the effect of surface wetting characteristics and dynamics resulting from a hemolymph drop impact, the first such study. In particular, hemolymph drops extracted from Acheta domesticus were dispensed from a range of heights to vary the kinetic impact on surfaces, which had widely varying water wetting behavior (from superhydrophilic to superhydrophobic). The impact dynamics were investigated with high-speed imaging while the dried residues were studied with optical microscopy. It was found that a superhydrophobic surface (based on thermoplastic with silica nano-particles) was able to significantly reduce hemolymph drop spreading, and even provide complete rebound when impacting on inclined surfaces. (C) 2015 Elsevier B.V. All rights reserved.