Enhanced Laplace Pressures for Functional Surfaces: Wicking, Switchability, and Selectivity
Name
Adv Materials Inter - 2022 - Wilke - Enhanced Laplace Pressures for Functional Surfaces Wicking Switchability and.pdf
Description
Published version
Size
1.1 MB
Format
Adobe PDF
Checksum (MD5)
4bda4c3a64d166af57f568482b8a4595
Author(s)
Wilke, Kyle L
Song, Youngsup
Lu, Zhengmao
Wang, Evelyn N
Date Issued
February 2023
Journal
Advanced Materials Interfaces
Publisher
Wiley
Citation
Wilke, Kyle L, Song, Youngsup, Lu, Zhengmao and Wang, Evelyn N. 2023. "Enhanced Laplace Pressures for Functional Surfaces: Wicking, Switchability, and Selectivity." Advanced Materials Interfaces, 10 (4).
Version
Final published version
Abstract
Wetting functionalities of rough surfaces are largely determined by the Laplace pressure generated across liquid–gas interfaces formed within surface structures. Typically, rough wetting surfaces create negative Laplace pressures, enabling capillary wicking, while rough non‐wetting surfaces create positive Laplace pressures, exhibiting fluid repellency. Here, with microfabricated reentrant structures, it is shown that the same surface can exhibit either a negative or positive Laplace pressure, regardless of its intrinsic wettability. This material‐independent Laplace pressure duality enables or enhances a range of wetting functionalities including wicking, switchability, and selectivity. On the same surface, capillary rise, capillary dip, and the combination of the two which leads to further enhancement of the total sustainable capillary height and Laplace pressure, the driving force for wicking is demonstrated. Further, active switching of wetting states between the hemiwicking and the repellent Cassie state on reentrant structures is shown. Moreover, with a water‐hexane mixture system, selective wetting of reentrant structures are demonstrated, that is, water can be selectively wicked or repelled in the presence of hexane, and vice versa. These functionalities are achieved, which would typically require complex chemical coatings, solely using surface structures, thus largely expanding the design space for a wide range of thermofluidic applications.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1002/admi.202201967
