Absence of an evaporation-driven wetting transition on omniphobic surfaces

Susarrey Arce, A. and Gomez Marin, A. and Nair, H. and Lefferts, L. and Gardeniers, J.G.E. and Lohse, D. and Houselt van, A. (2012) Absence of an evaporation-driven wetting transition on omniphobic surfaces. Soft matter, 8 (38). 9765 - 9770. ISSN 1744-683X

PDF
Restricted to UT campus only: Request a copy
355Kb

Abstract:	Surfaces that exhibit contact angles close to 180° for both polar and non-polar solvents are rare. Here we report the fabrication of such “omniphobic” surfaces by photolithography. We investigate their stability against a so-called wetting transition during evaporation of millimetric water droplets by systematically varying the shape and surface roughness of the micropillars on the surface. We show that a low edge curvature of the top of the micropillars strongly delays the transition, while it completely disappears when the surface roughness is increased. We compare these experimental findings with existing models that describe the Cassie–Baxter to Wenzel transition and conclude that new models are needed which include the hurdle of an energy barrier for the wetting transition. Our results reveal that by increasing the roughness of the micropillars we do not affect the apparent equilibrium contact angle of the droplets. The dynamic robustness of the surface is, however, dramatically enhanced by an increase of the surface roughness.
Item Type:	Article
Copyright:	© 2012 Royal Society of Chemistry
Faculty:	Science and Technology (TNW)
Research Group:	Mesoscale Chemical Systems (MCS) Catalytic Processes and Materials (CPM) Physics of Fluids (POF)
Link to this item:	http://purl.utwente.nl/publications/81376
Official URL:	http://dx.doi.org/10.1039/C2SM25746G
Export this item as:	BibTeX EndNote HTML Citation Reference Manager

Show download statistics for this publication

Repository Staff Only: item control page

Metis ID: 288011