Nanofilm with Directional Wetting and Adhesion Properties

Description:

The Naval Research Laboratory (NRL) and Pennsylvania State University have developed a nanofilm comprised of structured poly-(p-xylyene) (PPX) with directional wetting, adhesion, and droplet transport properties. The direction and extent of adhesion and wetability is adjusted through the formation of the PPX nanorods, which are fabricated with commercially available vapor deposition equipment. The result is a pattern of columns oriented at a non-perpendicular angle and a nanoscale surface roughness with unidirectional wetting properties. The film allows for water droplets to be pinned to the surface in several directions, including vertically. However, when the film is rotated to the release position, the microscale droplets are transported off the film smoothly and without deformation. The nanofilm’s ability to unidirectionally transport water droplets allows for numerous microfluidic and lab on chip applications. NRL has all rights to this technology.

Advantages/Features Include:

Directional transpost of fluid droplets on fluidic channels
Adhesion along one direction, release of water along opposite direction
Hydrophobic, contact angle equal to or greater than 90 degrees
Smooth microscale droplet motion
Decreased drag in release direction
PPX nanotubes are easily fabricated by a bottom up vapor-phase technique

Applications Include:

Microfluidic pumpless devices
Hydro turbine friction control
Antifouling surfaces
Biomedical coatings
Ice formation control
Moisture barriers
Anti-friction layers
Microelectronics cooling

References:

"An Engineered Anisotropic Nanofilm with Unidirectional Wetting Properties," Nature Materials 2010, 12, 1023-1028.
"Controlling the Wettability and Adhesion of Nanostructured Poly-(p-xylyene) Films," Langmuir 2007, 23, 11391-11395.

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Contact:

Naval Research Laboratory
Technology Transfer Office, Code 1004
techtran@research.nrl.navy.mil

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