Using anisotropic microscale topography to reduce the retention of water on aluminum

COLL 23

Andrew D. Sommers, asommers@uiuc.edu and Anthony M. Jacobi, a-jacobi@uiuc.edu. Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801
In this research, a method for fabricating controlled micro-scale, anisotropic topographical features on aluminum is described for the purpose of exploiting those features to affect the surface wettability. Our experimental data have shown that droplets placed on these micro-grooved aluminum surfaces using a micro-syringe exhibit an increased apparent contact angle, and for droplets condensed on these etched surfaces, up to a 50% reduction in the volume needed for the onset of droplet sliding is manifest. This water repellency is accomplished by the underlying anisotropic surface morphology which manipulates the droplet geometry and creates and exploits discontinuities in the three-phase contact line. In an effort to provide guidance for the development of these surfaces, a semi-empirical model for droplet retention on micro-grooved aluminum surfaces will also be presented.