A long-standing quest in material science has been the development of non-wettable superhydrophobic films based on a single organic material, without the requirement of fluorination or silane treatment. Here, such films and coatings, which are developed using colloidal gels of fullerite C and C nanocrystals, are described. It is illustrated that despite the high surface energy of these van der Waals molecular crystals their gelation can create films having self-affine fractal surfaces with multiscale roughness. Water droplets on resulting surfaces of fullerite films bead like a pearl resting in a Fakir state with contact angle exceeding 150°. The films are extremely water repellent and non-wettable; when submerged in water they stay dry up to 3 h even at a water depth of two feet and exhibit the plastron effect. A series of experiments are presented to provide comprehensive inspection of water droplet dynamics on these films. These include rolling, bouncing, squeezing, freezing, melting, evaporating; along with acidic and alkaline tests. Non-wettable films of such materials are unique as fullerites get photosensitized instantaneously generating extremely high yields (≈100%) of singlet oxygen ( O ) that can destroy viruses and bacteria; thereby enabling their use in rheology, water purification, and medicinal devices.
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http://dx.doi.org/10.1002/adma.202102108 | DOI Listing |
ACS Appl Bio Mater
July 2022
Acoustoelectronics Laboratory, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72, Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria.
Nowadays, the tremendous progress of nanotechnologies and materials science facilitates the fabrication of universal and multifunctional superhydrophobic surfaces on a large scale. Yet, integrating icephobic and anti-bioadhesive properties in an individual water-repellent functional coating, for addressing the difficulties faced by cryobiologists, aircraft, and seacraft manufacturers, is quite tricky but feasible if using nonpolar soot nanoparticles, whose fragility, however, impedes their industrial applicability. Here, we advance the current state-of-the-art to an extent, permitting the introduction of economically affordable and ultradurable non-wettable soot-based coatings.
View Article and Find Full Text PDFPolymers (Basel)
December 2021
Department of Mechanical Engineering, Korea National University of Transportation, Chungju 27469, Korea.
An initial drop shape can alter the bouncing dynamics and significantly decrease the residence time on superhydrophobic surfaces. Elliptical footprint drops show asymmetric dynamics owing to a pronounced flow driven by the initial drop shape. However, the fundamental understanding of the effect of viscosity on the asymmetric dynamics has yet to be investigated, although viscous liquid drop impact on textured surfaces is of scientific and industrial importance.
View Article and Find Full Text PDFLangmuir
September 2021
Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
The present study investigates the impact and freezing behavior of the droplets of surfactant solutions on non-wettable coatings at very low temperatures of -10 to -30 °C. Our goal is to elucidate the critical role of concentration, molecular weight, and ionic nature of surfactants on these phenomena. To achieve this goal, we used sodium dodecyl sulfate (anionic), hexadecyltrimethylammonium bromide (cationic), and -decanoyl--methylglucamine (nonionic) at four concentrations ranging from 0 to 2 × CMC (critical micelle concentration).
View Article and Find Full Text PDFAdv Mater
August 2021
NanoScience Technology Center, University of Central Florida, Orlando, FL, 32826, USA.
A long-standing quest in material science has been the development of non-wettable superhydrophobic films based on a single organic material, without the requirement of fluorination or silane treatment. Here, such films and coatings, which are developed using colloidal gels of fullerite C and C nanocrystals, are described. It is illustrated that despite the high surface energy of these van der Waals molecular crystals their gelation can create films having self-affine fractal surfaces with multiscale roughness.
View Article and Find Full Text PDFMaterials (Basel)
July 2020
School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China.
Liquid food adhesion on containers has increased food waste and pollution, which could be effectively alleviated with a superhydrophobic surface. In this research, the superhydrophobic coating was fabricated with edible soybean wax on different substrates by a spraying method. The coated surface showed excellent superhydrophobicity due to its microstructure formed by self-roughening, which could repel a variety of viscous liquid food with the apparent contact angle of 159 ± 2°.
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