TY - JOUR
T1 - Counterintuitive Wetting Transitions in Doubly Reentrant Cavities as a Function of Surface Make-Up, Hydrostatic Pressure, and Cavity Aspect Ratio
AU - Arunachalam, Sankara
AU - Ahmad, Zain
AU - Das, Ratul
AU - Mishra, Himanshu
N1 - KAUST Repository Item: Exported on 2020-10-09
Acknowledged KAUST grant number(s): BAS/1/1070-01-01
Acknowledgements: 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.
PY - 2020/10/7
Y1 - 2020/10/7
N2 - 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
AB - 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
UR - http://hdl.handle.net/10754/665494
UR - https://onlinelibrary.wiley.com/doi/10.1002/admi.202001268
U2 - 10.1002/admi.202001268
DO - 10.1002/admi.202001268
M3 - Article
SN - 2196-7350
SP - 2001268
JO - Advanced Materials Interfaces
JF - Advanced Materials Interfaces
ER -