To address the debates on whether superhydrophobic coatings can reduce fluid drag for underwater motions, we have achieved an underwater drag-reducing effect of large superhydrophobic submarine models with a feature size of 3.5 cm × 3.7 cm × 33.0 cm through sailing experiments of submarine models, modified with and without superhydrophobic surface under similar power supply and experimental conditions. The drag reduction rate reached as high as 15%. The fabrication of superhydrophobic coatings on a large area of submarine model surfaces was realized by immobilizing hydrophobic copper particles onto a precross-linked polydimethylsiloxane (PDMS) surface. The pre-cross-linking time was optimized at 20 min to obtain good superhydrophobicity for the underwater drag reduction effect by investigating the effect of pre-cross-linking on surface wettability and water adhesive property. We do believe that superhydrophobic coatings may provide a promising application in the field of drag-reducing of vehicle motions on or under the water surface.
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http://dx.doi.org/10.1021/la504451k | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Colour Science and Textile Chemistry Research Center, College of Textiles and Clothing, Qingdao University, Qingdao, Shandong 266071, China.
Superhydrophobic fabrics suffer from being commonly penetrated by moisture after laundering, seriously deteriorating their water repellency after air drying. Numerous researchers have successfully recovered superhydrophobicity by drying in fluid ovens; however, high energy consumption and equipment dependence limit practical applications. Herein, the superhydrophobic photothermal self-healing cotton fabric (SPS cotton fabric) was fabricated by depositing a composite layer of cellulose nanocrystal-MXene (C-MXene) and polyacrylate (PA) coatings on the cotton cloth.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Jožef Stefan Institute, Department of Physical and Organic Chemistry, Jamova c. 39, SI-1000 Ljubljana, Slovenia.
The study aimed to develop a superhydrophobic coating on the aluminium alloy 2024-T3 surface. The desired surface roughness and low surface energy were achieved with SiO nanoparticles, synthesised via the Stöber method and modified with alkyl silane (AS) or perfluoroalkyl silane (FAS). To enhance particle adhesion to the alloy substrate, nanoparticles were incorporated into a hybrid sol-gel coating composed of tetraethyl orthosilicate, methyl methacrylate, and 3-methacryloxypropyl trimethoxysilane.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Occupational Health Engineering, Faculty of Health, Qazvin University of Medical Sciences, Qazvin, Iran.
The purpose of this research is to investigate the potential of chemical modification to improve the hydrophobic properties and thermal stability of bamboo fibers and to evaluate the sound absorption performance of raw and modified fibers. To achieve this goal, bamboo fibers were modified using stearic acid coatings and aluminum hydroxide nanoparticles. The results showed that the modification of fibers with stearic acid (STA) can improve the contact angle and hydrophobicity of bamboo fibers, so that for modified fibers with a concentration of 0.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
School of Engineering, University of Liverpool, Liverpool, L69 3GH, United Kingdom.
Hypothesis: We hypothesise that superhydrophobic surfaces can achieve effective interfacial slip and drag reduction even under non-Newtonian, shear-thinning fluid flows. Unlike Newtonian fluids, where slip is primarily influenced by viscosity and surface tension, we anticipate that the shear-thinning nature of these fluids may enhance slip length and drag reduction.
Experiments And Numerical Analysis: The superhydrophobic surfaces used in this study, featuring a dual-scale random topography, were fabricated via a spray coating process, and low-concentration xanthan gum solutions (50-250 ppm) were used as model shear-thinning fluids of low elasticity.
Nanomaterials (Basel)
January 2025
Qiqihar Inspection and Testing Center, Qiqihar 161006, China.
Superhydrophobic paper-based functional materials have emerged as a sustainable solution with a wide range of applications due to their unique water-repelling properties. Inspired by natural examples like the lotus leaf, these materials combine low surface energy with micro/nanostructures to create air pockets that maintain a high contact angle. This review provides an in-depth analysis of recent advancements in the development of superhydrophobic paper-based materials, focusing on methodologies for modification, underlying mechanisms, and performance in various applications.
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