Microcavity-array superhydrophobic surfaces: Limits of the model

Superhydrophobic surfaces formed of microcavities can be designed with specific desired advancing and receding contact angles using a new model described by us in prior work. Here, we discuss the limits of validity of the model, and explore the application of the model to surfaces fabricated with sm...

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Bibliographic Details
Published in:Journal of applied physics 2013-11, Vol.114 (17), p.174911
Main Authors: Salvadori, M. C., Oliveira, M. R. S., Spirin, R., Teixeira, F. S., Cattani, M., Brown, I. G.
Format: Article
Language:English
Subjects:
Applied physics
Contact
Contact angle
Holes
Hydrophobic surfaces
Hydrophobicity
Microcavities
Pressurized water
Submerging
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Summary:Superhydrophobic surfaces formed of microcavities can be designed with specific desired advancing and receding contact angles using a new model described by us in prior work. Here, we discuss the limits of validity of the model, and explore the application of the model to surfaces fabricated with small cavities of radius 250 nm and with large cavities of radius 40 μm. The Wenzel model is discussed and used to calculate the advancing and receding contact angles for samples for which our model cannot be applied. We also consider the case of immersion of a sample containing microcavities in pressurized water. A consideration that then arises is that the air inside the cavities can be dissolved in the water, leading to complete water invasion into the cavities and compromising the superhydrophobic character of the surface. Here, we show that this effect does not destroy the surface hydrophobia when the surface is subsequently removed from the water.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4829003