caa a22 4500 530098768 20181217030326.0 cr unu---uuuuu 181026e20141113xx s 000 0 eng 10.3929/ethz-b-000093216 doi 10.1038/srep07029 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/93216 Morphing and vectoring impacting droplets by means of wettability-engineered surfaces [Elektronische Daten] [Thomas M. Schutzius, Gustav; id_orcid 0000-0003-0658-6084 Graeber, Mohamed Elsharkawy, James Oreluk, Constantine M. Megaridis] Sci Rep Open access ethresearch Driven by its importance in nature and technology, droplet impact on solid surfaces has been studied for decades. To date, research on control of droplet impact outcome has focused on optimizing pre-impact parameters, e.g., droplet size and velocity. Here we follow a different, post-impact, surface engineering approach yielding controlled vectoring and morphing of droplets during and after impact. Surfaces with patterned domains of extreme wettability (high or low) are fabricated and implemented for controlling the impact process during and even after rebound —a previously neglected aspect of impact studies on non-wetting surfaces. For non-rebound cases, droplets can be morphed from spheres to complex shapes —without unwanted loss of liquid. The procedure relies on competition between surface tension and fluid inertial forces, and harnesses the naturally occurring contact-line pinning mechanisms at sharp wettability changes to create viable dry regions in the spread liquid volume. Utilizing the same forces central to morphing, we demonstrate the ability to rebound orthogonally-impacting droplets with an additional non-orthogonal velocity component. We theoretically analyze this capability and derive a We−.25 dependence of the lateral restitution coefficient. This study offers wettability-engineered surfaces as a new approach to manipulate impacting droplet microvolumes, with ramifications for surface microfluidics and fluid-assisted templating applications. Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0 ethresearch Applied physics ethresearch fluid dynamics ethresearch Fluid dynamics ethresearch Schutzius Thomas M. joint author Graeber Gustav; id_orcid 0000-0003-0658-6084 joint author Elsharkawy Mohamed joint author Oreluk James joint author Megaridis Constantine M. joint author Scientific Reports London : Nature Publishing Group 4, p. 7029 2045-2322 http://hdl.handle.net/20.500.11850/93216 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/93216 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Schutzius Thomas M. joint author ETHRESEARCH 700 1- Graeber Gustav; id_orcid 0000-0003-0658-6084 joint author ETHRESEARCH 700 1- Elsharkawy Mohamed joint author ETHRESEARCH 700 1- Oreluk James joint author ETHRESEARCH 700 1- Megaridis Constantine M. joint author ETHRESEARCH 773 0- Scientific Reports London : Nature Publishing Group 4, p. 7029 2045-2322 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access