Uni-directional liquid spreading on asymmetric nanostructured surfaces
Top Cited Papers
- 28 March 2010
- journal article
- Published by Springer Science and Business Media LLC in Nature Materials
- Vol. 9 (5), 413-417
- https://doi.org/10.1038/nmat2726
Abstract
Controlling surface wettability and liquid spreading on patterned surfaces is of significant interest for a broad range of applications, including DNA microarrays, digital lab-on-a-chip, anti-fogging and fog-harvesting, inkjet printing and thin-film lubrication. Advancements in surface engineering, with the fabrication of various micro/nanoscale topographic features, and selective chemical patterning on surfaces, have enhanced surface wettability and enabled control of the liquid film thickness and final wetted shape. In addition, groove geometries and patterned surface chemistries have produced anisotropic wetting, where contact-angle variations in different directions resulted in elongated droplet shapes. In all of these studies, however, the wetting behaviour preserves left-right symmetry. Here, we demonstrate that we can harness the design of asymmetric nanostructured surfaces to achieve uni-directional liquid spreading, where the liquid propagates in a single preferred direction and pins in all others. Through experiments and modelling, we determined that the spreading characteristic is dependent on the degree of nanostructure asymmetry, the height-to-spacing ratio of the nanostructures and the intrinsic contact angle. The theory, based on an energy argument, provides excellent agreement with experimental data. The insights gained from this work offer new opportunities to tailor advanced nanostructures to achieve active control of complex flow patterns and wetting on demand.Keywords
This publication has 29 references indexed in Scilit:
- Multilayer liquid spreading on superhydrophilic nanostructured surfacesApplied Physics Letters, 2009
- Water droplet lubrication between hydrophilic and hydrophobic surfacesJournal of Physics: Conference Series, 2007
- Imbibition by polygonal spreading on microdecorated surfacesNature Materials, 2007
- Anisotropic wetting on tunable micro-wrinkled surfacesSoft Matter, 2007
- Nanoporosity-Driven Superhydrophilicity: A Means to Create Multifunctional Antifogging CoatingsLangmuir, 2006
- Non-sticking dropsReports on Progress in Physics, 2005
- Dewetting of conducting polymer inkjet droplets on patterned surfacesNature Materials, 2004
- Ultrahydrophobic Surfaces. Effects of Topography Length Scales on WettabilityLangmuir, 2000
- Liquid Morphologies on Structured Surfaces: From Microchannels to MicrochipsScience, 1999
- Contact Angles for Liquid Drops at a Model Heterogeneous Surface Consisting of Alternating and Parallel Hydrophobic/Hydrophilic StripsLangmuir, 1996