Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces
Type
ArticleKAUST Department
Biological and Environmental Sciences and Engineering (BESE) DivisionWater Desalination and Reuse Research Center (WDRC)
KAUST Grant Number
BAS/1/1070-01-01BAS/1/1070-01-03
BAS/1/1070-01-02
Date
2017-06-05Permanent link to this record
http://hdl.handle.net/10754/624900
Metadata
Show full item recordAbstract
Omniphobic surfaces, i.e. which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact, and preventing applications in harsh environments. There is, thus, a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nano-texturing rather than via chemical make-up, with notable success having been achieved for silica surfaces with doubly reentrant micropillars. However, we found a critical limitation of microtextures comprising of pillars that they undergo catastrophic wetting transitions (apparent contact angles, θr → 0° from θr > 90°) in the presence of localized physical damages/defects or on immersion in wetting liquids. In response, a doubly reentrant cavity microtexture is introduced, which can prevent catastrophic wetting transitions in the presence of localized structural damage/defects or on immersion in wetting liquids. Remarkably, our silica surfaces with doubly reentrant cavities could exhibited apparent contact angles, θr ≈ 135° for mineral oil, where the intrinsic contact angle, θo ≈ 20°. Further, when immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising of doubly reentrant cavities might enable applications of conventional materials without chemical modifications, especially in scenarios that are prone to localized damages or immersion in wetting liquids, e.g. hydrodynamic drag reduction and membrane distillation.Citation
Domingues E, Arunachalam S, Mishra H (2017) Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces. ACS Applied Materials & Interfaces. Available: http://dx.doi.org/10.1021/acsami.7b03526.Sponsors
The authors thank KAUST Baseline Research Funding (BAS/1/1070-01-01), Center Affiliated Fund (BAS/1/1070-01-03) and Start-up funds (BAS/1/1070-01-02).Publisher
American Chemical Society (ACS)ISSN
1944-82441944-8252
PubMed ID
28580784Additional Links
http://pubs.acs.org/doi/abs/10.1021/acsami.7b03526ae974a485f413a2113503eed53cd6c53
10.1021/acsami.7b03526
Scopus Count
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