Abstract
Biphilic surfaces show great promise for water harvesting, dehumidification, and condensation applications. Capable of manipulating the nucleation and growth of the condensate droplets while maintaining low surface-condensate adhesion, a carefully designed biphilic surface not only allows for coalescence-induced droplet jumping, but also shows good flooding-resistance. However, the complex and costly fabrication, usually consisting of incorporating hydrophilic spots onto a hydrophobic substrate, hinders the wide-spread utilization of biphilic surfaces. Here we use laser ablation followed by thermal oxidation to fabricate CuO hierarchical biphilic surfaces on Cu substrates. The fabricated surfaces do not need additional chemical modification, as the prepared samples spontaneously transitioned from superhydrophilic to superhydrophobic due to the deposition of the airborne volatile organic compounds (VOCs). Interestingly, the dependence of the nanowire features on the curvature of the micro-topography enables local roughness variation and wetting gradients on a three-dimensional curved surface. The hilltops of the micro-cones are hydrophilic due to the presence of sparse and short nanowires, while in the valleys and ridges, the dense high-aspect-ratio nanowires together with the adsorbed airborne VOCs results in local superhydrophobicity. The as-prepared surfaces are globally superhydrophobic showing a water advancing contact angle above 160°. Condensation experiments under optical microscopy reveal that condensate prefers to nucleate at the hilltop hydrophilic areas, while droplets forming within the hydrophobic valleys show good mobility. Durable dropwise condensation and coalescence-induced droplet jumping are achieved on the CuO hierarchical surface, with ≈ 80% enhancement of the water harvesting rate over the conventional Cu hydrophobic surfaces in atmospheric water vapor condensation conditions.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2125-2132 |
| 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
- Biphilic
- Condensation
- Manufacturing
- Nano/Micro
- Roughness Variation
- Water Harvesting
ASJC Scopus subject areas
- Fluid Flow and Transfer Processes
- Condensed Matter Physics
- Mechanical Engineering
Cite this
Atmosphere-mediated and roughness-variation-induced biphilic surfaces. / Yan, Xiao; Chen, Feng; Li, Hang; Sett, Soumyadip; Li, Longnan; Huang, Zhiyong; Bo, Hanliang; Miljkovic, Nenad.
In: International Heat Transfer Conference, Vol. 2018-August, 01.01.2018, p. 2125-2132.Research output: Contribution to journal › Conference article
}
TY - JOUR
T1 - Atmosphere-mediated and roughness-variation-induced biphilic surfaces
AU - Yan, Xiao
AU - Chen, Feng
AU - Li, Hang
AU - Sett, Soumyadip
AU - Li, Longnan
AU - Huang, Zhiyong
AU - Bo, Hanliang
AU - Miljkovic, Nenad
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Biphilic surfaces show great promise for water harvesting, dehumidification, and condensation applications. Capable of manipulating the nucleation and growth of the condensate droplets while maintaining low surface-condensate adhesion, a carefully designed biphilic surface not only allows for coalescence-induced droplet jumping, but also shows good flooding-resistance. However, the complex and costly fabrication, usually consisting of incorporating hydrophilic spots onto a hydrophobic substrate, hinders the wide-spread utilization of biphilic surfaces. Here we use laser ablation followed by thermal oxidation to fabricate CuO hierarchical biphilic surfaces on Cu substrates. The fabricated surfaces do not need additional chemical modification, as the prepared samples spontaneously transitioned from superhydrophilic to superhydrophobic due to the deposition of the airborne volatile organic compounds (VOCs). Interestingly, the dependence of the nanowire features on the curvature of the micro-topography enables local roughness variation and wetting gradients on a three-dimensional curved surface. The hilltops of the micro-cones are hydrophilic due to the presence of sparse and short nanowires, while in the valleys and ridges, the dense high-aspect-ratio nanowires together with the adsorbed airborne VOCs results in local superhydrophobicity. The as-prepared surfaces are globally superhydrophobic showing a water advancing contact angle above 160°. Condensation experiments under optical microscopy reveal that condensate prefers to nucleate at the hilltop hydrophilic areas, while droplets forming within the hydrophobic valleys show good mobility. Durable dropwise condensation and coalescence-induced droplet jumping are achieved on the CuO hierarchical surface, with ≈ 80% enhancement of the water harvesting rate over the conventional Cu hydrophobic surfaces in atmospheric water vapor condensation conditions.
AB - Biphilic surfaces show great promise for water harvesting, dehumidification, and condensation applications. Capable of manipulating the nucleation and growth of the condensate droplets while maintaining low surface-condensate adhesion, a carefully designed biphilic surface not only allows for coalescence-induced droplet jumping, but also shows good flooding-resistance. However, the complex and costly fabrication, usually consisting of incorporating hydrophilic spots onto a hydrophobic substrate, hinders the wide-spread utilization of biphilic surfaces. Here we use laser ablation followed by thermal oxidation to fabricate CuO hierarchical biphilic surfaces on Cu substrates. The fabricated surfaces do not need additional chemical modification, as the prepared samples spontaneously transitioned from superhydrophilic to superhydrophobic due to the deposition of the airborne volatile organic compounds (VOCs). Interestingly, the dependence of the nanowire features on the curvature of the micro-topography enables local roughness variation and wetting gradients on a three-dimensional curved surface. The hilltops of the micro-cones are hydrophilic due to the presence of sparse and short nanowires, while in the valleys and ridges, the dense high-aspect-ratio nanowires together with the adsorbed airborne VOCs results in local superhydrophobicity. The as-prepared surfaces are globally superhydrophobic showing a water advancing contact angle above 160°. Condensation experiments under optical microscopy reveal that condensate prefers to nucleate at the hilltop hydrophilic areas, while droplets forming within the hydrophobic valleys show good mobility. Durable dropwise condensation and coalescence-induced droplet jumping are achieved on the CuO hierarchical surface, with ≈ 80% enhancement of the water harvesting rate over the conventional Cu hydrophobic surfaces in atmospheric water vapor condensation conditions.
KW - Biphilic
KW - Condensation
KW - Manufacturing
KW - Nano/Micro
KW - Roughness Variation
KW - Water Harvesting
UR - http://www.scopus.com/inward/record.url?scp=85060366027&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85060366027&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:85060366027
VL - 2018-August
SP - 2125
EP - 2132
JO - International Heat Transfer Conference
JF - International Heat Transfer Conference
SN - 2377-424X
ER -