Symmetric and asymmetric meniscus collapse in wetting transition on submerged structured surfaces

Pengyu Lv, Yahui Xue, Hao Liu, Yipeng Shi, Peng Xi, Hao Lin, Huiling Duan

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The wetting transition from the Cassie-Baxter to the Wenzel state is a phenomenon critically pertinent to the functionality of microstructured superhydrophobic surfaces. This work focuses on the last stage of the transition, when the liquid-gas interface touches the bottom of the microstructure, which is also known as the "collapse" phenomenon. The process was examined in situ on a submerged surface patterned with cylindrical micropores using confocal microscopy. Both symmetric and asymmetric collapses were observed. The latter significantly shortens the progression of the metastable state prior to the collapse when compared with the former and hence may affect the lifespan of superhydrophobicity. Further experiments identified that asymmetric collapse were induced by impurities due to prior use of the structure. The problem is thus of broad relevance, since endurance through cycles is a practical requirement for these functional surfaces. Finally, the use of hierarchical structures is proposed as a remedy. The embedded self-cleaning mechanism serves to effectively remove the impurities, so as to avoid the triggering mechanism for asymmetric collapses.

Original languageEnglish (US)
Pages (from-to)1248-1254
Number of pages7
JournalLangmuir
Volume31
Issue number4
DOIs
Publication statusPublished - Feb 3 2015

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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