Water droplet bouncing on a hierarchical superhydrophobic surface fabricated by hydrothermal synthesis and ultraprecision machining

Yexiang Fu, Fuwang Zhao, Zejia Zhao, Hui Tang, Suet To, Ching Hsiang Cheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review


The ability of a water droplet to bounce on a superhydrophobic surface is an important indication of the surface wetting properties. In this study, a method integrating hydrothermal synthesis with ultraprecision machining (UPM) is reported for fabricating a hierarchical NiO-FAS-17 coated copper microgroove surface. Contact angles and water droplet bouncing behaviors were tested to evaluate the hydrophobicity of sample surfaces. Large contact angles over 160° and small contact angle hysteresis not exceeding 5° were recorded, showing good water repellency for the NiO-FAS-17 coating. The droplet bouncing results presented a larger first rebound height and stronger tendency of droplet break-up on the hierarchical NiO-FAS-17 coated microgroove surface in comparison with the NiO-FAS-17 coated flat surface, indicating a better hydrophobicity of the hierarchical surface. This reveals that the hydrophobicity of a surface can be enhanced by introducing UPM fabricated microgroove patterns into nanostructured surfaces that already possess good hydrophobicity.

Original languageEnglish
JournalJournal of Adhesion Science and Technology
Publication statusAccepted/In press - 2022


  • hierarchical structures
  • hydrothermal
  • superhydrophobic
  • ultraprecision machining
  • Water droplet bouncing

ASJC Scopus subject areas

  • Chemistry(all)
  • Mechanics of Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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