Counterintuitive Wetting Transitions in Doubly Reentrant Cavities as a Function of Surface Make-Up, Hydrostatic Pressure, and Cavity Aspect Ratio

dc.contributor.authorArunachalam, Sankara
dc.contributor.authorAhmad, Zain
dc.contributor.authorDas, Ratul
dc.contributor.authorMishra, Himanshu
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentEnvironmental Science and Engineering
dc.contributor.departmentEnvironmental Science and Engineering Program
dc.date.accepted2020-08-20
dc.date.accessioned2020-11-24T12:42:43Z
dc.date.available2020-11-24T12:42:43Z
dc.date.issued2020-11-20
dc.date.published-online2020-11-20
dc.date.published-print2020-11
dc.date.submitted2020-07-17
dc.description.abstractSurfaces that entrap air underwater serve numerous practical applications, such as mitigating cavitation erosion and reducing frictional drag. These surfaces typically rely on perfluorinated coatings. However, the non-biodegradability and fragility of the coatings limit practical applications. Thus, coating-free, sustainable, and robust approaches are desirable. Recently, a microtexture comprising doubly reentrant cavities (DRCs) has been demonstrated to entrap air on immersion in wetting liquids. While this is a promising approach, insights into the effects of surface chemistry, hydrostatic pressure, and cavity dimensions on wetting transitions in DRCs remain unavailable. In response, Cassie-to-Wenzel transitions into circular DRCs submerged in water are investigated and compared with those in cylindrical “simple” cavities (SCs). It is found that at low hydrostatic pressures (≈50 Pa), DRCs with hydrophilic (θo ≈ 40°) and hydrophobic (θo ≈ 112°) make-ups fill within 105 and 107 s, respectively, while SCs with hydrophilic make-up fill within <10−2 s. Under elevated hydrostatic pressure (P ≤ 90 kPa), counterintuitively, DRCs with hydrophobic make-up fill dramatically faster than the commensurate SCs. This comprehensive report should provide a rational framework for harnessing microtexturing and surface chemistry toward coating-free liquid repellency.
dc.description.sponsorshipS.A. and Z.A. contributed equally to this work. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST) under the award number BAS/1/1070-01-01. The authors thank Mr. Ulrich Buttner and Mr. Ahad A. Sayed from the KAUST Core Labs for their assistance with the microfabrication. The authors thank Dr. Wei Xu for helping with the confocal measurements and Mr. Edelberto Manalastas for his assistance in the fabrication of the pressure chamber for the confocal experiments. The authors thank Ms. Jamilya Nauruzbayeva for processing confocal images using Imaris software and proofreading the manuscript. The authors also thank Dr. Meng Shi (KAUST) and Dr. Yair Kaufman (University of California Santa Barbara) for fruitful discussions.
dc.eprint.versionPublisher's Version/PDF
dc.identifier.citationArunachalam, S., Ahmad, Z., Das, R., & Mishra, H. (2020). Counterintuitive Wetting Transitions in Doubly Reentrant Cavities as a Function of Surface Make-Up, Hydrostatic Pressure, and Cavity Aspect Ratio. Advanced Materials Interfaces, 7(22), 2070121. doi:10.1002/admi.202001268
dc.identifier.doi10.1002/admi.202001268
dc.identifier.doi10.1002/admi.202070121
dc.identifier.issn2196-7350
dc.identifier.issn2196-7350
dc.identifier.issue22
dc.identifier.journalAdvanced Materials Interfaces
dc.identifier.pages2070121
dc.identifier.urihttp://hdl.handle.net/10754/666098
dc.identifier.volume7
dc.publisherWiley
dc.relation.urlhttps://onlinelibrary.wiley.com/doi/10.1002/admi.202070121
dc.rightsThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.titleCounterintuitive Wetting Transitions in Doubly Reentrant Cavities as a Function of Surface Make-Up, Hydrostatic Pressure, and Cavity Aspect Ratio
dc.typeArticle
display.details.left<span><h5>License</h5>http://creativecommons.org/licenses/by/4.0/<br><br><h5>Type</h5>Article<br><br><h5>Authors</h5><a href="https://repository.kaust.edu.sa/search?query=orcid.id:0000-0003-3685-3913&spc.sf=dc.date.issued&spc.sd=DESC">Arunachalam, Sankara</a> <a href="https://orcid.org/0000-0003-3685-3913" target="_blank"><img src="https://repository.kaust.edu.sa/server/api/core/bitstreams/82a625b4-ed4b-40c8-865a-d6a5225a26a4/content" width="16" height="16"/></a><br><a href="https://repository.kaust.edu.sa/search?query=orcid.id:0000-0002-4462-7716&spc.sf=dc.date.issued&spc.sd=DESC">Ahmad, Zain</a> <a href="https://orcid.org/0000-0002-4462-7716" target="_blank"><img src="https://repository.kaust.edu.sa/server/api/core/bitstreams/82a625b4-ed4b-40c8-865a-d6a5225a26a4/content" width="16" height="16"/></a><br><a href="https://repository.kaust.edu.sa/search?query=orcid.id:0000-0003-1008-0086&spc.sf=dc.date.issued&spc.sd=DESC">Das, Ratul</a> <a href="https://orcid.org/0000-0003-1008-0086" target="_blank"><img src="https://repository.kaust.edu.sa/server/api/core/bitstreams/82a625b4-ed4b-40c8-865a-d6a5225a26a4/content" width="16" height="16"/></a><br><a href="https://repository.kaust.edu.sa/search?query=orcid.id:0000-0001-8759-7812&spc.sf=dc.date.issued&spc.sd=DESC">Mishra, Himanshu</a> <a href="https://orcid.org/0000-0001-8759-7812" target="_blank"><img src="https://repository.kaust.edu.sa/server/api/core/bitstreams/82a625b4-ed4b-40c8-865a-d6a5225a26a4/content" width="16" height="16"/></a><br><br><h5>KAUST Department</h5><a href="https://repository.kaust.edu.sa/search?spc.sf=dc.date.issued&spc.sd=DESC&f.department=Water Desalination and Reuse Research Center (WDRC),equals">Water Desalination and Reuse Research Center (WDRC)</a><br><a href="https://repository.kaust.edu.sa/search?spc.sf=dc.date.issued&spc.sd=DESC&f.department=Biological and Environmental Sciences and Engineering (BESE) Division,equals">Biological and Environmental Sciences and Engineering (BESE) Division</a><br><a href="https://repository.kaust.edu.sa/search?spc.sf=dc.date.issued&spc.sd=DESC&f.department=Environmental Science and Engineering,equals">Environmental Science and Engineering</a><br><a href="https://repository.kaust.edu.sa/search?spc.sf=dc.date.issued&spc.sd=DESC&f.department=Environmental Science and Engineering Program,equals">Environmental Science and Engineering Program</a><br><br><h5>KAUST Grant Number</h5>BAS/1/1070-01-01<br><br><h5>Online Publication Date</h5>2020-11-20<br><br><h5>Print Publication Date</h5>2020-11<br><br><h5>Date</h5>2020-11-20<br><br><h5>Submitted Date</h5>2020-07-17</span>
display.details.right<span><h5>Abstract</h5>Surfaces that entrap air underwater serve numerous practical applications, such as mitigating cavitation erosion and reducing frictional drag. These surfaces typically rely on perfluorinated coatings. However, the non-biodegradability and fragility of the coatings limit practical applications. Thus, coating-free, sustainable, and robust approaches are desirable. Recently, a microtexture comprising doubly reentrant cavities (DRCs) has been demonstrated to entrap air on immersion in wetting liquids. While this is a promising approach, insights into the effects of surface chemistry, hydrostatic pressure, and cavity dimensions on wetting transitions in DRCs remain unavailable. In response, Cassie-to-Wenzel transitions into circular DRCs submerged in water are investigated and compared with those in cylindrical “simple” cavities (SCs). It is found that at low hydrostatic pressures (≈50 Pa), DRCs with hydrophilic (θo ≈ 40°) and hydrophobic (θo ≈ 112°) make-ups fill within 105 and 107 s, respectively, while SCs with hydrophilic make-up fill within <10−2 s. Under elevated hydrostatic pressure (P ≤ 90 kPa), counterintuitively, DRCs with hydrophobic make-up fill dramatically faster than the commensurate SCs. This comprehensive report should provide a rational framework for harnessing microtexturing and surface chemistry toward coating-free liquid repellency.<br><br><h5>Citation</h5>Arunachalam, S., Ahmad, Z., Das, R., & Mishra, H. (2020). Counterintuitive Wetting Transitions in Doubly Reentrant Cavities as a Function of Surface Make-Up, Hydrostatic Pressure, and Cavity Aspect Ratio. Advanced Materials Interfaces, 7(22), 2070121. doi:10.1002/admi.202001268<br><br><h5>Acknowledgements</h5>S.A. and Z.A. contributed equally to this work. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST) under the award number BAS/1/1070-01-01. The authors thank Mr. Ulrich Buttner and Mr. Ahad A. Sayed from the KAUST Core Labs for their assistance with the microfabrication. The authors thank Dr. Wei Xu for helping with the confocal measurements and Mr. Edelberto Manalastas for his assistance in the fabrication of the pressure chamber for the confocal experiments. The authors thank Ms. Jamilya Nauruzbayeva for processing confocal images using Imaris software and proofreading the manuscript. The authors also thank Dr. Meng Shi (KAUST) and Dr. Yair Kaufman (University of California Santa Barbara) for fruitful discussions.<br><br><h5>Publisher</h5><a href="https://repository.kaust.edu.sa/search?spc.sf=dc.date.issued&spc.sd=DESC&f.publisher=Wiley,equals">Wiley</a><br><br><h5>Journal</h5><a href="https://repository.kaust.edu.sa/search?spc.sf=dc.date.issued&spc.sd=DESC&f.journal=Advanced Materials Interfaces,equals">Advanced Materials Interfaces</a><br><br><h5>DOI</h5><a href="https://doi.org/10.1002/admi.202001268">10.1002/admi.202001268</a><br><a href="https://doi.org/10.1002/admi.202070121">10.1002/admi.202070121</a><br><br><h5>Additional Links</h5>https://onlinelibrary.wiley.com/doi/10.1002/admi.202070121</span>
kaust.acknowledged.supportUnitCore Labs
kaust.acknowledged.supportUnitKAUST Core Lab
kaust.grant.numberBAS/1/1070-01-01
kaust.personArunachalam, Sankara
kaust.personAhmad, Zain
kaust.personDas, Ratul
kaust.personMishra, Himanshu
orcid.authorArunachalam, Sankara::0000-0003-3685-3913
orcid.authorAhmad, Zain::0000-0002-4462-7716
orcid.authorDas, Ratul::0000-0003-1008-0086
orcid.authorMishra, Himanshu::0000-0001-8759-7812
orcid.id0000-0001-8759-7812
orcid.id0000-0003-1008-0086
orcid.id0000-0002-4462-7716
orcid.id0000-0003-3685-3913
refterms.dateFOA2020-11-24T12:43:19Z
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