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 language | English (US) |
|---|---|
| Pages (from-to) | 2333-2340 |
| Number of pages | 8 |
| Journal | International Heat Transfer Conference |
| Volume | 2018-August |
| State | Published - Jan 1 2018 |
| Event | 16th International Heat Transfer Conference, IHTC 2018 - Beijing, China Duration: Aug 10 2018 → Aug 15 2018 |
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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 journal › Conference article
}
TY - JOUR
T1 - Coalescence-induced droplet jumping on atmospheric-mediated superhydrophobic surfaces
AU - Yan, Xiao
AU - Chen, Feng
AU - Sett, Soumyadip
AU - Feng, Lezhou
AU - Oh, Junho
AU - Cha, Hyeongyun
AU - Li, Longnan
AU - Huang, Zhiyong
AU - Miljkovic, Nenad
PY - 2018/1/1
Y1 - 2018/1/1
N2 - 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.
AB - 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.
KW - Coalescence-induced droplet jumping
KW - Coatless Superhydrophobicity
KW - Condensation
KW - Hydrocarbons
KW - Manufacturing
KW - Nano/Micro
KW - VOCs
KW - Volatile Organic Compounds
UR - http://www.scopus.com/inward/record.url?scp=85060381379&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85060381379&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:85060381379
VL - 2018-August
SP - 2333
EP - 2340
JO - International Heat Transfer Conference
JF - International Heat Transfer Conference
SN - 2377-424X
ER -