Static and dynamic characterization of robust superhydrophobic surfaces built from nano-flowers on silicon micro-post arrays

Longquan Chen, Zhiyong Xiao, Philip C H Chan, Yi-Kuen Lee

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Superhydrophobic nano-flower surfaces were fabricated using MEMS technology and microwave plasma-enhanced chemical vapor deposition (MPCVD) of carbon nanotubes on silicon micro-post array surfaces. The nano-flower structures can be readily formed within 1-2 min on the micro-post arrays with the spacing ranging from 25 to 30 μm. The petals of the nano-flowers consisted of clusters of multi-wall carbon nanotubes. Patterned nano-flower structures were characterized using various microscopy techniques. After MPCVD, the apparent contact angle (160 ± 0.2°), abbreviated as ACA (defined as the measured angle between the apparent solid surface and the tangent to the liquid-fluid interface), of the nano-flower surfaces increased by 139% compared with that of the silicon micro-post arrays. The measured ACA of the nano-flower surface is consistent with the predicted ACA from a modified Cassie-Baxter equation. A high-speed CCD camera was used to study droplet impact dynamics on various micro/nanostructured surfaces. Both static testing (ACA and sliding angle) and droplet impact dynamics demonstrated that, among seven different micro/nanostructured surfaces, the nano-flower surfaces are the most robust superhydrophobic surfaces. © 2010 IOP Publishing Ltd.
Original languageEnglish (US)
Pages (from-to)105001
JournalJournal of Micromechanics and Microengineering
Issue number10
StatePublished - Sep 1 2010
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): SA-C0040/UK-C0016
Acknowledgements: The authors would like to express the sincerest gratitude to Professor Robert H Austin from Princeton University for his helpful discussion and suggestions. They acknowledge Professor Tong-Xi Yu's Impact Dynamics Laboratory for providing the high-speed CCD camera for the study of droplet impact dynamics. They are also grateful to Dr Hongkai Wu for the silanization treatment of the silicon substrate and micro-post array surfaces, and the staff at the Nanoelectronic Fabrication Facility and the Material Characterization and Preparation Facility. The research was partially supported by a grant from Hong Kong Research Grants Council (ref no. 615907) and partially supported by a grant from King Abdullah University of Science and Technology (KAUST award no. SA-C0040/UK-C0016).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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