Evaporation-Triggered Wetting Transition for Water Droplets upon Hydrophobic Microstructures

Tsai, Peichun and Lammertink, Rob G.H. and Wessling, Matthias and Lohse, Detlef (2010) Evaporation-Triggered Wetting Transition for Water Droplets upon Hydrophobic Microstructures. Physical Review Letters, 104 (11). p. 116102. ISSN 0031-9007

Preview

PDF
1211Kb

Abstract:	When placed on rough hydrophobic surfaces, water droplets of diameter larger than a few millimeters can easily form pearls, as they are in the Cassie-Baxter state with air pockets trapped underneath the droplet. Intriguingly, a natural evaporating process can drive such a Fakir drop into a completely wetting (Wenzel) state. Our microscopic observations with simultaneous side and bottom views of evaporating droplets upon transparent hydrophobic microstructures elucidate the water-filling dynamics and suggest the mechanism of this evaporation-triggered transition. For the present material the wetting transition occurs when the water droplet size decreases to a few hundreds of micrometers in radius. We present a general global energy argument which estimates the interfacial energies depending on the drop size and can account for the critical radius for the transition
Item Type:	Article
Copyright:	© American Physical Society
Faculty:	Science and Technology (TNW)
Research Group:	Physics of Fluids (POF) Membrane Science and Technology (MST)
Link to this item:	http://purl.utwente.nl/publications/79182
Official URL:	http://dx.doi.org/10.1103/PhysRevLett.104.116102
Export this item as:	BibTeX EndNote HTML Citation Reference Manager

Repository Staff Only: item control page

Metis ID: 265509