Laplace pressure driven single-droplet jumping on structured surfaces

Xiao Yan, Yimeng Qin, Feipeng Chen, Guanlei Zhao, Soumyadip Sett, Muhammad Jahidul Hoque, Kazi Fazle Rabbi, Xueqian Zhang, Zi Wang, Longnan Li, Feng Chen, Jie Feng, Nenad Miljkovic

Research output: Contribution to journalArticlepeer-review

Abstract

Droplet transport on, and shedding from, surfaces is ubiquitous in nature and is a key phenomenon governing applications including biofluidics, self-cleaning, anti-icing, water harvesting, and electronics thermal management. Conventional methods to achieve spontaneous droplet shedding enabled by surface-droplet interactions suffer from low droplet transport velocities and energy conversion efficiencies. Here, by spatially confining the growing droplet and enabling relaxation via rationally designed grooves, we achieve single-droplet jumping of micrometer and millimeter droplets with dimensionless jumping velocities v∗ approaching 0.95, significantly higher than conventional passive approaches such as coalescence-induced droplet jumping (v∗ ≈ 0.2-0.3). The mechanisms governing single-droplet jumping are elucidated through the study of groove geometry and local pinning, providing guidelines for optimized surface design. We show that rational design of grooves enables flexible control of droplet-jumping velocity, direction, and size via tailoring of local pinning and Laplace pressure differences. We successfully exploit this previously unobserved mechanism as a means for rapid removal of droplets during steam condensation. Our study demonstrates a passive method for fast, efficient, directional, and surface-pinning-Tolerant transport and shedding of droplets having micrometer to millimeter length scales.

Original languageEnglish (US)
JournalACS Nano
Early online dateOct 14 2020
DOIs
StateE-pub ahead of print - Oct 14 2020

Keywords

  • condensation
  • groove
  • micro/nanostructured
  • pinning
  • single-droplet jumping
  • superhydrophobic

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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