The possibility of forming a hydrophobic metallic interface is shown when it is micrometrically textured. On such surface obtained by gold coating the polymer honeycomb template, the apparent contact angle of water was observed to be close to or greater than 90 degrees . The metal hydrophobicity is explained by trapping air inside pores of pattern according to the Cassie-Baxter wetting model. The agreement between calculated and observed values of the apparent contact angle justifies the applicability of this model in the present case. Formation of the acute local (Young) angle on the pore surface is provided by its concave form.
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http://dx.doi.org/10.1016/j.jcis.2006.06.016 | 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
October 2024
Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtzplatz 1, Eggenstein-Leopoldshafen 76344, Germany.
Artificial microtextures adopted to achieve adhesion reduction help avoid the vulnerability associated with chemical coatings. Most current microtextures strongly rely on biological inspiration or designers' physical intuition. There are also manufacturing challenges due to the complex geometrical configurations.
View Article and Find Full Text PDFLangmuir
October 2024
Department of Chemical Engineering, University of Liège, B6A, Allée du Six Août 13, 4000 Liège, Belgium.
Numerous applications of nanoporous materials require their pores to be filled with liquids. In spite of its huge technological importance, the conditions for the wetting of nanometer-sized pores and its phenomenology are still poorly understood. We report on capillary rise experiments with water in carbon xerogels, with synchrotron small-angle scattering used to follow the process in situ at the nanometer scale.
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