In this paper, we provide a theory for the Wenzel and the Cassie-Baxter states of an electrolyte drop on charged surfaces. An electric double layer (EDL) develops when the electrolyte drop comes in contact with the charged surface. Therefore, the EDL free energy affects these states by triggering a hydrophilicity-inducing tendency. Consequently, an originally hydrophilic condition leads to a superhydrophilic Wenzel state, and an originally hydrophobic condition leads to a less hydrophobic Wenzel state. For the Cassie-Baxter state, this gives rise to the most remarkable situation of a hydrophilic (as compared to the original) Cassie-Baxter state.
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http://dx.doi.org/10.1103/PhysRevE.86.011603 | DOI Listing |
Langmuir
November 2024
Wide Range Flight Engineering Science and Applications Center, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
The wetting transition behaviors of polymeric droplets on microcavity surfaces are familiar and play a vital role in micromanufacturing, microfluidics, and printing industries. Despite previous research indicating that microcavity surfaces can precisely control the droplet wetting state, the understanding of the complex effects of droplet spreading, surface morphology, and property of polymeric droplet on wetting transitions remains incomplete. The air-liquid interfaces (ALIs) typically arise from the entrapped air beneath the droplet on microcavity surfaces, adopting a metastable wetting state caused by either bubble escape or dissolution.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Pl. 1, 76344 Eggenstein-Leopoldshafen, Germany.
Variations from equilibrium Young's angle, known as contact angle hysteresis (CAH), are frequently observed upon droplet deposition on a solid surface. This ubiquitous phenomenon indicates the presence of multiple local surface energy minima for the sessile droplet. Previous research primarily explains CAH via considering macroscopic roughness, such as topographical defects, which alter the effective interfacial energy between the fluid phase and the solid phase, thereby shifting the global surface energy minimum.
View Article and Find Full Text PDFAdv Mater
January 2025
Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulju-gun, Ulsan, 44919, Republic of Korea.
Water-repellent superhydrophobic surfaces are ubiquitous in nature. The fundamental understanding of bio/bio-inspired structures facilitates practical applications surmounting metastable superhydrophobicity. Typically, the hierarchical structure and/or reentrant morphology have been employed hitherto to suppress the Cassie-Baxter to Wenzel transition (CWT).
View Article and Find Full Text PDFLangmuir
July 2024
State Key Laboratory of Engines, Tianjin University, Tianjin 300350, China.
The water-repellence properties of superhydrophobic surfaces make them promising for many applications. However, in some extreme environments, such as high humidities and low temperatures, condensation on the surface is inevitable, which induces the loss of surface superhydrophobicity. In this study, we propose a freezing-melting strategy to achieve the dewetting transition from the Wenzel state to the Cassie-Baxter state.
View Article and Find Full Text PDFAdv Sci (Weinh)
September 2024
Dept. of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Uusimaa, 02150, Finland.
Superhydrophobic surfaces (SHS) exhibit a pronounced ability to resist wetting. When immersed in water, water does not penetrate between the microstructures of the SHS. Instead, a thin layer of trapped gas remains, i.
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