Facile creation of hierarchical PDMS microstructures with extreme underwater superoleophobicity for anti-oil application in microfluidic channels

Dong Wu, Si-Zhu Wu, Qi-Dai Chen, Shuai Zhao, Hao Zhang, Jian Jiao, Jeffrey A. Piersol, Jian-Nan Wang, Hong-Bo Sun, Lei Jiang

Research output: Contribution to journalReview ArticleResearchpeer-review

99 Citations (Scopus)

Abstract

Composition modification and surface microstructures have been widely utilized in interface science to improve the surface performance. In this paper, we observed a significant improvement of oil contact angle (CA) from 66 ± 2° to 120 ± 4° by introducing a radical silanol group on a flat PDMS surface through oxygen plasma pretreatment. By combining surface microstructures and plasma modification, we produced three kinds of superoleophobic surfaces: 20 μm pitch micropillar arrays, 2.5 μm pitch micropillar arrays and gecko foot-like hierarchical microstructures. Among them, the hierarchical surface with high surface roughness showed extreme underwater superoleophobicity, which featured ultrahigh CA (175 ± 3°) and ultrasmall sliding angle (<1°). Quantitative measurements demonstrated that these superoleophobic surfaces exhibited distinct adhesive behaviors, by which they were interpreted as Wenzel's, Cassie's and the Lotus state, respectively. A microfluidic channel with superoleophobic microstructures was further created by novel curve-assisted imprint lithography, and the characterization based on anti-oil contamination applications was carried out and discussed. We believe that the superoleophobic surfaces will power broad applications in oil microdroplet transportation, anti-oil channels and droplet microfluidic systems.

Original languageEnglish
Pages (from-to)3873-3879
Number of pages7
JournalLab on a Chip
Volume11
Issue number22
DOIs
Publication statusPublished - 21 Nov 2011
Externally publishedYes

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