Selective liquid directional steering enabled by dual-scale reentrant ratchets

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

8 Scopus Citations
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  • Chao Zhang
  • Wei Wang
  • Zhaokun Wang
  • Zuankai Wang

Related Research Unit(s)


Original languageEnglish
Article number025504
Journal / PublicationInternational Journal of Extreme Manufacturing
Issue number2
Online published27 Apr 2023
Publication statusPublished - Jun 2023



Achieving well-controlled directional steering of liquids is of great significance for both fundamental study and practical applications, such as microfluidics, biomedicine, and heat management. Recent advances allow liquids with different surface tensions to select their spreading directions on a same surface composed of macro ratchets with dual reentrant curvatures. Nevertheless, such intriguing directional steering function relies on 3D printed sophisticated structures and additional polishing process to eliminate the inevitable microgrooves-like surface deficiency generated from printing process, which increases the manufacturing complexity and severally hinders practical applications. Herein, we developed a simplified dual-scale structure that enables directional liquid steering via a straightforward 3D printing process without the need of any physical and chemical post-treatment. The dual-scale structure consists of macroscale tilt ratchet equipped with a reentrant tip and microscale grooves that decorated on the whole surface along a specific orientation. Distinct from conventional design requiring the elimination of microgrooves-like surface deficiency, we demonstrated that the microgrooves of dual-scale structure play a key role in delaying or promoting the local flow of liquids, tuning of which could even enable liquids select different spreading pathways. This study provides a new insight for developing surfaces with tunable multi-scale structures, and also advances our fundamental understanding of the interaction between liquid spreading dynamics and surface topography. © 2023 The Author(s). Published by IOP Publishing Ltd on behalf of the IMMT.

Research Area(s)

  • dual-scale structures, liquid spreading, reentrant ratchet

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