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

Lee BJ, Zhang Z, Baek S, Kim S, Kim D, Yong K - Sci Rep (2016)

Bottom Line: Among diverse approaches for drag reduction, superhydrophobic surfaces have been mainly researched due to their high drag reducing efficiency.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.

View Article: PubMed Central - PubMed

Affiliation: Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, POSTECH (Pohang University of Science and Technology), Pohang, 790-784 Korea.

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.

No MeSH data available.


(a) Scheme for the fabrication process of a SiC/Si hierarchical structure. (b,c) Top and cross-sectional SEM images of SiC nanowire arrays. (d,e) Top and cross-sectional SEM images of Si micropost arrays. (f–h) Top, magnified and cross-sectional SEM images of SiC/Si hierarchical structures. (i) XRD patterns of as-prepared SiC/Si hierarchical structures.
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f1: (a) Scheme for the fabrication process of a SiC/Si hierarchical structure. (b,c) Top and cross-sectional SEM images of SiC nanowire arrays. (d,e) Top and cross-sectional SEM images of Si micropost arrays. (f–h) Top, magnified and cross-sectional SEM images of SiC/Si hierarchical structures. (i) XRD patterns of as-prepared SiC/Si hierarchical structures.

Mentions: A SiC nanowires arraywith high density was synthesized by carbothermal reduction of WO3 and graphite on a NiO-catalyzed p-type Si substrate5559. As shown in Fig. 1b, the SiC nanowire arrays had rough and randomly aligned interlocked net structures with a high aspect ratio of 20–50 nm diameter and were tens of micrometers in length. Also the SiC nanowires were stacked layer upon layer with a uniform thickness of ~20 μm (Fig. 1c). The growth of highly dense, long and stacked SiC nanowires was based on solid-liquid-solid (SLS) mechanism, in which the Si substrate is used as a Si source material for SiC nanowires formation. Carbothermal reduction of WO3 and graphite produces COx gases, which are used as a carbon source for the growth of SiC. Then, the reaction between SiOx and COx produces SiC, which nucleates on the surface and grows into SiC nanowires.


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

Lee BJ, Zhang Z, Baek S, Kim S, Kim D, Yong K - Sci Rep (2016)

(a) Scheme for the fabrication process of a SiC/Si hierarchical structure. (b,c) Top and cross-sectional SEM images of SiC nanowire arrays. (d,e) Top and cross-sectional SEM images of Si micropost arrays. (f–h) Top, magnified and cross-sectional SEM images of SiC/Si hierarchical structures. (i) XRD patterns of as-prepared SiC/Si hierarchical structures.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837397&req=5

f1: (a) Scheme for the fabrication process of a SiC/Si hierarchical structure. (b,c) Top and cross-sectional SEM images of SiC nanowire arrays. (d,e) Top and cross-sectional SEM images of Si micropost arrays. (f–h) Top, magnified and cross-sectional SEM images of SiC/Si hierarchical structures. (i) XRD patterns of as-prepared SiC/Si hierarchical structures.
Mentions: A SiC nanowires arraywith high density was synthesized by carbothermal reduction of WO3 and graphite on a NiO-catalyzed p-type Si substrate5559. As shown in Fig. 1b, the SiC nanowire arrays had rough and randomly aligned interlocked net structures with a high aspect ratio of 20–50 nm diameter and were tens of micrometers in length. Also the SiC nanowires were stacked layer upon layer with a uniform thickness of ~20 μm (Fig. 1c). The growth of highly dense, long and stacked SiC nanowires was based on solid-liquid-solid (SLS) mechanism, in which the Si substrate is used as a Si source material for SiC nanowires formation. Carbothermal reduction of WO3 and graphite produces COx gases, which are used as a carbon source for the growth of SiC. Then, the reaction between SiOx and COx produces SiC, which nucleates on the surface and grows into SiC nanowires.

Bottom Line: Among diverse approaches for drag reduction, superhydrophobic surfaces have been mainly researched due to their high drag reducing efficiency.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.

View Article: PubMed Central - PubMed

Affiliation: Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, POSTECH (Pohang University of Science and Technology), Pohang, 790-784 Korea.

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.

No MeSH data available.