Limits...
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.


Related in: MedlinePlus

(a) Digital image of superhydrophobicSiC/Si hierarchical structures submerged in water. (b) Schematic images for total reflections at the water-air interface of SiC/Si hierarchical structures. (c) Schematic images for the diffusion process of the air interlayer in water. (d) Relative intensity transitions and τd values of SiC nanowire arrays, Si micropost arrays and SiC/Si hierarchical structures when submerged in water at the depth of 15 cm. (e) Relative intensity transitions of SiC/Si hierarchical structures at 4 different immersion depths (5, 10, 15 and 20 cm). (f) Graph of τdvs the immersion depth of the submerged surfaces.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4837397&req=5

f3: (a) Digital image of superhydrophobicSiC/Si hierarchical structures submerged in water. (b) Schematic images for total reflections at the water-air interface of SiC/Si hierarchical structures. (c) Schematic images for the diffusion process of the air interlayer in water. (d) Relative intensity transitions and τd values of SiC nanowire arrays, Si micropost arrays and SiC/Si hierarchical structures when submerged in water at the depth of 15 cm. (e) Relative intensity transitions of SiC/Si hierarchical structures at 4 different immersion depths (5, 10, 15 and 20 cm). (f) Graph of τdvs the immersion depth of the submerged surfaces.

Mentions: The as-prepared superhydrophobic SiC nanowire arrays and SiC/Si hierarchical structures showed a visual change when they were submerged in water (Fig. 3a). When the incident angle of light is greater than a critical angle (θc = 48° for the water/air interface) of total reflectance, the air interlayer reflects all the incident light and submerged surfaces look mirror-like and silvery (Fig. 3b).


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) Digital image of superhydrophobicSiC/Si hierarchical structures submerged in water. (b) Schematic images for total reflections at the water-air interface of SiC/Si hierarchical structures. (c) Schematic images for the diffusion process of the air interlayer in water. (d) Relative intensity transitions and τd values of SiC nanowire arrays, Si micropost arrays and SiC/Si hierarchical structures when submerged in water at the depth of 15 cm. (e) Relative intensity transitions of SiC/Si hierarchical structures at 4 different immersion depths (5, 10, 15 and 20 cm). (f) Graph of τdvs the immersion depth of the submerged surfaces.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: (a) Digital image of superhydrophobicSiC/Si hierarchical structures submerged in water. (b) Schematic images for total reflections at the water-air interface of SiC/Si hierarchical structures. (c) Schematic images for the diffusion process of the air interlayer in water. (d) Relative intensity transitions and τd values of SiC nanowire arrays, Si micropost arrays and SiC/Si hierarchical structures when submerged in water at the depth of 15 cm. (e) Relative intensity transitions of SiC/Si hierarchical structures at 4 different immersion depths (5, 10, 15 and 20 cm). (f) Graph of τdvs the immersion depth of the submerged surfaces.
Mentions: The as-prepared superhydrophobic SiC nanowire arrays and SiC/Si hierarchical structures showed a visual change when they were submerged in water (Fig. 3a). When the incident angle of light is greater than a critical angle (θc = 48° for the water/air interface) of total reflectance, the air interlayer reflects all the incident light and submerged surfaces look mirror-like and silvery (Fig. 3b).

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.


Related in: MedlinePlus