Bio-inspired dewetted surfaces based on SiC/Si interlocked structures for enhanced-underwater stability and regenerative-drag reduction capability.

By Junghan Lee,Kijung Yong,Sangkuk Kim,Seunghyun Baek,Donghyung Kim,Zhuo Zhang

doi:10.1038/srep24653

By Junghan Lee, Kijung Yong + Show 4 more

Open Access

https://doi.org/10.1038/srep24653

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Abstract

Drag reduction has become a serious issue in recent years in terms of energy conservation and environmental protection. Among diverse approaches for drag reduction, superhydrophobic surfaces have been mainly researched due to their high drag reducing efficiency. However, due to limited lifetime of plastron (i.e., air pockets) on superhydrophobic surfaces in underwater, the instability of dewetted surfaces has been a sticking point for practical applications. This work presents a breakthrough in improving the underwater stability of superhydrophobic surfaces by optimizing nanoscale surface structures using SiC/Si interlocked structures. These structures have an unequaled stability of underwater superhydrophobicity and enhance drag reduction capabilities,with a lifetime of plastron over 18 days and maximum velocity reduction ratio of 56%. Furthermore, through photoelectrochemical water splitting on a hierarchical SiC/Si nanostructure surface, the limited lifetime problem of air pockets was overcome by refilling the escaping gas layer, which also provides continuous drag reduction effects.

Highlights

Structures, have been reported to enhance the lifetime of the air interlayer[53,54]
In all different Fg s, the superhydrophobic surfaces and SLIPS showed the highest velocities while the superhydrophilic surfaces had the lowest ones. These results indicate that the superhydrophobic surfaces and SLIPS had drag reducing properties while superhydrophilic surfaces had drag enhancement properties
Regenerative drag reducing surfaces have been successfully developed by combining superhydrophobicity and solar water splitting

Summary

Introduction

Structures, have been reported to enhance the lifetime of the air interlayer[53,54]. In this study we have developed new SiC/Si interlocked hierarchical structures using a carbothermal reduction based synthesis method[55]. Compared to previously reported structures, our surface drastically improved the lifetime of the air interlayer and showed the highest stability of underwater superhydrophobicity due to its unique networking structure[47,56]. The underwater superhydrophobicity was successfully restored by the PEC reaction of the SiC/Si interlocked net structures and provided a regenerative drag reduction capability as a results. Our study presents a novel hierarchical interlocked net structure with a high gas capture capability and presents an unprecedented method for providing a continuously regenerating drag reduction property

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Results

Conclusion