Self-removal of condensed water on the legs of water striders

Qianbin Wang, Xi Yao, Huan Liu, David Quere, Lei Jiang

Research output: Contribution to journalArticleResearchpeer-review

124 Citations (Scopus)

Abstract

The ability to control drops and their movements on phobic surfaces is important in printing or patterning, microfluidic devices, and water-repellent materials. These materials are always micro-/nanotextured, and a natural limitation of repellency occurs when drops are small enough (as in a dew) to get trapped in the texture. This leads to sticky Wenzel states and destroys the superhydrophobicity of the material. Here, we show that droplets of volume ranging from femtoliter (fL) to microliter (µL) can be self-removed from the legs of water striders. These legs consist of arrays of inclined tapered setae decorated by quasi-helical nanogrooves. The different characteristics of this unique texture are successively exploited as water condenses, starting from self-penetration and sweeping effect along individual cones, to elastic expulsion between flexible setae, followed by removal at the anisotropic leg surface. We envision that this antifogging effect at a very small scale could inspire the design of novel applicable robust water-repellent materials for many practical applications.
Original languageEnglish
Pages (from-to)9247-9252
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number30
DOIs
Publication statusPublished - 28 Jul 2015
Externally publishedYes

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