Bioinspired Underwater Respirable Superhydrophobic Skin with a Microcone-Nanoparticle Structure for Sustainable Drag...

Area of Science:

• Materials Science
• Fluid Dynamics
• Surface Chemistry

Background:

• Superhydrophobic (SH) surfaces reduce flow resistance using gas-liquid interfaces in applications like microfluidics and shipping.
• Maintaining an air layer (plastron) on SH surfaces underwater for drag reduction and restoring it after wetting remains a significant challenge.

Purpose of the Study:

• To develop an underwater respirable skin (URS) with a microcone-nanoparticle structure inspired by water spiders.
• To investigate the drag reduction and plastron restoration capabilities of the developed URS.
• To analyze the trade-offs between drag reduction and plastron restoration.

Main Methods:

• Fabrication of URS with varying geometric parameters using laser microfabrication and chemical vapor deposition.
• Experimental testing to measure drag reduction rates.
• Air jetting to assess plastron restoration from a fully wetted state.
• Theoretical and numerical analysis to understand underlying mechanisms.

Main Results:

• The URS demonstrated complete plastron restoration from a fully wetted state in 11.6 seconds.
• A drag reduction rate of 15.7% ± 0.2% was achieved.
• Theoretical and numerical findings indicated a conflicting relationship between drag reduction and plastron restoration.

Conclusions:

• The developed URS shows promise for marine vehicle coatings, offering sustainable drag reduction.
• The study provides insights into balancing plastron restoration and drag reduction for underwater applications.
• This research offers new methodologies for designing advanced drag reduction surfaces.