Fighting Freezing Rain: Effects of Surface Texturing and Temperature on Droplet Impact

Reduction of droplet-to-surface contact time and area has a wide variety of industrial benefits and is a primary focus of anti-icing technology. It is known that contact dynamics may be affected to some degree by surface texture, droplet radius, variations in the hydrophobic coating, and temperature variation of the droplet or surface, among other factors. The team is dedicated to quantifying the influence of these factors and assessing how strongly they each affect droplet impact. In this study, poly(1H,1H,2H,2H-perfluorodecyl acrylate) (pPFDA) is deposited via initiated chemical vapor deposition (iCVD) on a smooth silicon surface as well as femtosecond lasers roughened aluminum surfaces. The surfaces are each imaged at the millimeter scale to quantify roughness. The coated substrates are placed on a peltier device at varying temperatures, and droplet impacts are then measured and evaluated at a high framerate to yield kinetic information. The roughened surfaces saw a large reduction in contact time and a much more elastic collision between the droplet and the surface. Droplets adhered to chilled surfaces more strongly, and this effect was enhanced on rougher surfaces.