Coalescence-induced droplet jumping on atmospheric-mediated superhydrophobic surfaces

Xiao Yan, Feng Chen, Soumyadip Sett, Lezhou Feng, Junho Oh, Hyeongyun Cha, Longnan Li, Zhiyong Huang, Nenad Miljkovic

Research output: Contribution to journalConference article

Abstract

Coalescence-induced droplet jumping has received much attention over the past decade due to its ability to passively remove microscale droplets thereby enhancing condensation heat transfer, anti-icing, self-cleaning, and energy harvesting performance. However, droplet-jumping relies on surface superhydrophobicity, which results from the joint contributions of surface roughness and low-surface-energy conformal coatings such as alkyl and perfluorinated molecules. In spite of fantastic laboratory scale demonstrations, jumping-droplet surfaces fail to gain traction in real-life applications due to poor durability of the low surface energy coatings required to achieve superhydrophobicity. Here, we demonstrate that by exposing rationally designed intrinsically hydrophilic copper-based hierarchically structured CuO surfaces to ambient air, robust superhydrophobicity enabling coalescence-induced droplet jumping can be achieved. The as-prepared CuO surfaces experienced a transition from superhydrophilic to superhydrophobic with final apparent advancing contact angle and roll-off angle of >160° and <10°, respectively. X-ray photoelectron spectroscopy (XPS) confirmed that the wettability transition from wetting to non-wetting arises due to adsorption of airborne volatile organic compounds (VOCs) on the high-aspect-ratio and high-surface-area nanostructures. Due to the permanent and reliable source of VOCs in ambient air, the superhydrophobicity was shown to be retrievable after organic solvent and plasma cleaning. Most importantly, high-speed optical microscopy revealed the presence of stable coalescence-induced droplet jumping during atmospheric water vapor condensation. Our work not only promises an economic and facile way of fabricating superhydrophobic surfaces without the need for application of low-surface-energy chemistries, it also develops a platform for the development of next-generation durable superhydrophobic surfaces that can self-heal in the presence of ambient air.

Original languageEnglish (US)
Pages (from-to)2333-2340
Number of pages8
JournalInternational Heat Transfer Conference
Volume2018-August
StatePublished - Jan 1 2018
Event16th International Heat Transfer Conference, IHTC 2018 - Beijing, China
Duration: Aug 10 2018Aug 15 2018

Fingerprint

Coalescence
coalescing
Interfacial energy
surface energy
Volatile Organic Compounds
volatile organic compounds
Volatile organic compounds
cleaning
Wetting
Condensation
Cleaning
air
condensation
Air
coatings
Coatings
ice formation
Traction (friction)
Energy harvesting
traction

Keywords

  • Coalescence-induced droplet jumping
  • Coatless Superhydrophobicity
  • Condensation
  • Hydrocarbons
  • Manufacturing
  • Nano/Micro
  • VOCs
  • Volatile Organic Compounds

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Coalescence-induced droplet jumping on atmospheric-mediated superhydrophobic surfaces. / Yan, Xiao; Chen, Feng; Sett, Soumyadip; Feng, Lezhou; Oh, Junho; Cha, Hyeongyun; Li, Longnan; Huang, Zhiyong; Miljkovic, Nenad.

In: International Heat Transfer Conference, Vol. 2018-August, 01.01.2018, p. 2333-2340.

Research output: Contribution to journalConference article

Yan, X, Chen, F, Sett, S, Feng, L, Oh, J, Cha, H, Li, L, Huang, Z & Miljkovic, N 2018, 'Coalescence-induced droplet jumping on atmospheric-mediated superhydrophobic surfaces', International Heat Transfer Conference, vol. 2018-August, pp. 2333-2340.
Yan X, Chen F, Sett S, Feng L, Oh J, Cha H et al. Coalescence-induced droplet jumping on atmospheric-mediated superhydrophobic surfaces. International Heat Transfer Conference. 2018 Jan 1;2018-August:2333-2340.
Yan, Xiao ; Chen, Feng ; Sett, Soumyadip ; Feng, Lezhou ; Oh, Junho ; Cha, Hyeongyun ; Li, Longnan ; Huang, Zhiyong ; Miljkovic, Nenad. / Coalescence-induced droplet jumping on atmospheric-mediated superhydrophobic surfaces. In: International Heat Transfer Conference. 2018 ; Vol. 2018-August. pp. 2333-2340.
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AU - Cha, Hyeongyun

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