One-step process for dual-scale ratchets with enhanced mobility of Leidenfrost droplets

Cong Liu, Kuan Sun, Chenguang Lu, Junpeng Su, Libao Han, Zuankai Wang, Yahua Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

9 Citations (Scopus)


Hypothesis: Droplet depositing onto hot surfaces above the so-called Leidenfrost temperature will float on a cushion of its own vapor. The vapor flow below the drop could be rectified by asymmetric surface textures, resulting the self-propelled droplet motion. Asymmetric structures like ratchets are used to rectify Leidenfrost droplet movement. Hence, it is possible to enhance the droplet mobility using surfaces with combined asymmetric macro/micro-structures. Experiments: Continuous scale-like microcraters stacked end-to-end were fabricated on steel surfaces by wire electrical discharge machining (WEDM). The crater orientation always vectored towards the machining direction (MD), which oriented the droplet motion. Further, by integrating micro and macro-ratchets, dual-scale ratchets were constructed by one-step process using WEDM. The travelling velocities of Leidenfrost droplets on dual-scale and traditional single-scale ratchets were compared and the enhanced mechanism on dual-scale ratchets was analyzed. Findings: One-step process was developed to fabricate transport platforms for Leidenfrost droplets, that continuous scale-like microcraters formed simultaneously on the macroratchets. The highest droplet travelling velocity was achieved compared to previous research. Further study shows that the enhanced drop mobility is attributed to the dual-scale roughness which endows a larger propelling force. This finding presents a high-efficiency method to fabricate transport platforms for Leidenfrost droplets.

Original languageEnglish
Pages (from-to)229-234
Number of pages6
JournalJournal of Colloid and Interface Science
Publication statusPublished - 1 Jun 2020
Externally publishedYes


  • Directional transport
  • Dual-scale roughness
  • Leidenfrost droplet
  • Wire electrical discharge machining

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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