Recoverable underwater superhydrophobicity from a fully wetted state via dynamic air spreading

Yiping Zhao; Zhao Xu; Lu Gong; Shu Yang; Hongbo Zeng; Chunju He; Dengteng Ge; Lili Yang

doi:10.1016/j.isci.2021.103427

Recoverable underwater superhydrophobicity from a fully wetted state via dynamic air spreading

iScience. 2021 Nov 11;24(12):103427. doi: 10.1016/j.isci.2021.103427. eCollection 2021 Dec 17.

Authors

Yiping Zhao^{1

2}, Zhao Xu^{1

2}, Lu Gong³, Shu Yang⁴, Hongbo Zeng³, Chunju He¹, Dengteng Ge², Lili Yang¹

Affiliations

¹ State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
² Institute of Functional Materials, Donghua University, Shanghai 201620, China.
³ Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
⁴ Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadelphia, PA 19104, USA.

Abstract

Maintaining the superhydrophobicity underwater offers drag resistance reduction, antifouling, anti-corrosion, noise reduction, and gas collection for boat hulls and submarine vehicles. However, superhydrophobicity typically does not last long underwater since the Cassie state is metastable. Here, we report a reversible and localized recovery of superhydrophobicity from the fully wetted state via air bubble spreading. Composed of sparse fluorinated chained nanoparticles, the submerged surface shows super-low energy barrier for bubble attachment. Especially the recovered plastron exhibits excellent longevity. Based on a simplified, truncated nanocone model, the dynamic spreading of bubbles is analyzed considering two basic parameters, i.e., surface geometric structure and surface energy (which appeared as intrinsic water contact angle). Numerical simulation results via COMSOL confirms the effect of geometric structure on bubble spreading. This investigation will not only offer new insights for the design of robust recoverable superhydrophobic surfaces but also broaden the applications of superhydrophobic coatings.

Keywords: Materials science; Nanomaterials; Surface chemistry.