The plastron on superhydrophobic surfaces has seldom

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the plastron on superhydrophobic surfaces has seldom been reported [38-40]. In the present study, the superhydrophobic T-3 coating was immersed in water to a depth of 5 cm for 24 h, and its effect on the plastron stability was observed. We observed a stable plastron layer for an immersion time of up to 8 h, and the shiny appearance of the plastron gradually started to dim after 16 and 24 h of immersion ( Fig. 8 ). This decay in the plastron is due to the diffusion of the trapped air into the water (Laplace pressure), which causes the water to intrude into the rough structure [41]. However, after continuous immersion in water for 48 h, the silvery plastron layer had completely disappeared from the superhydrophobic T-3 coating surface. After removal from the water, a thin water layer was observed on the
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Page 13 of 28 Accepted Manuscript coating surface (complete wetting); conversely, after drying at 60 °C for 1 h, the superhydrophobic state was recovered. Zhang et al. [42] also observed the static, hydraulic, pressure-driven transformation of the superhydrophobic state of lotus leaves into a complete wetting state. However, the superhydrophobicity of the lotus leaves was regained by simple nitrogen flushing. 4. Conclusions An optically transparent and superhydrophobic coating on glass was prepared by the simple one-step sol-gel processing of long-chain FAS. The coating exhibited a rough, wrinkled, hill-like surface morphology, and the water drops assumed a spherical shape on this surface with a contact angle of 169° and a sliding angle of less than 5°. A stable plastron was observed on the superhydrophobic surface under the application of hydraulic pressure [43]. The prepared superhydrophobic coating exhibited an excellent self-cleaning performance and such optically transparent superhydrophobic coatings are essential for self-cleaning applications. The superhydrophobic wetting state was preserved under the impact of a high- speed water jet, however, the coating showed poor mechanical durability and easily got scratched by 9B grade hard pencil. Though the coating was transparent, superhydrophobic and showed self-cleaning properties, it lacks the mechanical properties. Usually, the superhydrophobic coatings are not mechanically stable due to its high surface roughness which gets easily damaged during mechanical rubbing [44]. There is huge scope in improving the hardness of the superhydrophobic coatings. In present sol-gel system, the inclusion of different micro/-nanoparticles in the sol-gel matrix can contribute to enhance
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Page 14 of 28 Accepted Manuscript the mechanical stability of the coating [45]. The further experiments are under process in our laboratory. Acknowledgements: We greatly appreciate the support of the National Natural Science Foundation of China (21101056, 21105021). The research was also supported by KETEP 20124030200120 and 20133030010890.
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Page 15 of 28 Accepted Manuscript References 1. Liu, Y.;Moevius, L.;Xu, X.;Qian, T.;Yeomans, J.M. and Wang, Z., Pancake bouncing on superhydrophobic surfaces. Nat Phys, 2014. 10 (7): p. 515 519.
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  • Fall '19
  • The Land, Surface tension, Contact angle, superhydrophobic coatings

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