June 07, 2016 Volume 12 Issue 21

Designfax weekly eMagazine

Subscribe Today!
image of Designfax newsletter


View Archives


Manufacturing Center
Product Spotlight

Modern Applications News
Metalworking Ideas For
Today's Job Shops

Tooling and Production
Strategies for large
metalworking plants

Wings: Graphene de-icer coating does double duty

Rice University scientists have advanced their graphene-based de-icer to serve a dual purpose. The new material still melts ice from wings and wires when conditions get too cold. But if the air is above 7 deg F, ice won't form at all.

The Rice lab of chemist James Tour gave its de-icer superhydrophobic (water-repelling) capabilities that passively prevent water from freezing above 7 deg F. The tough film that forms when the de-icer is sprayed on a surface is made of atom-thin graphene nanoribbons that are conductive, so the material can also be heated with electricity to melt ice and snow in colder conditions.

Rice scientists have modified their graphene-based de-icer to resist the formation of ice well below the freezing point and added superhydrophobic capabilities. The robust film is intended for use in extreme environments as well as on aircraft, power lines, and ships. [Illustration courtesy of the Tour Group]





The material can be spray-coated, making it suitable for large applications like aircraft, power lines, radar domes, and ships, according to the researchers. The study was published in May in the American Chemical Society journal ACS Applied Materials and Interfaces.

"We've learned to make an ice-resistant material for milder conditions in which heating isn't even necessary, but having the option is useful," Tour said. "What we now have is a very thin, robust coating that can keep large areas free of ice and snow in a wide range of conditions."

Tour, lead authors Tuo Wang, a Rice graduate student, and Yonghao Zheng, a Rice postdoctoral researcher, and their colleagues tested the film on glass and plastic.

Test samples show a graphene nanoribbon-based film developed at Rice University with both passive and active de-icing properties. When the film at left is heated without an application of lubricants, ice melts but water droplets remain on the surface. With lubricants, at right, ice begins to melt and slides off. The material may be suitable for de-icing and anti-icing applications in extreme environments. [Images courtesy of the Tour Group]





Materials are superhydrophobic if they have a water-contact angle larger than 150 degrees. The term refers to the angle at which the surface of the water meets the surface of the material. The greater the beading, the higher the angle. An angle of 0 degrees is basically a puddle, while a maximum angle of 180 degrees defines a sphere just touching the surface.

The Rice films use graphene nanoribbons modified with a fluorine compound to enhance their hydrophobicity. They found that nanoribbons modified with longer perfluorinated chains resulted in films with a higher contact angle, suggesting that the films are tunable for particular conditions, Tour said.

Warming test surfaces to room temperature and cooling again had no effect on the film's properties, he said.

The researchers discovered that below 7 deg F, water would condense within the structure's pores, causing the surface to lose both its superhydrophobic and ice-phobic properties. At that point, applying at least 12 V of electricity warmed them enough to retain its repellant properties.

Applying 40 V to the film brought it to room temperature, even if the ambient temperature was -25 deg F. Ice allowed to form at that temperature melted after 90 seconds of resistive heating.

The researchers found that while effective, the de-icing mode did not remove water completely, as some remained trapped in the pores between linked nanoribbon bundles. Adding a lubricant with a low melting point (-61 deg F) to the film made the surface slippery, sped de-icing, and saved energy.

Co-authors of the paper are Rice alumnus Abdul-Rahman Raji, now a postdoctoral researcher at the University of Cambridge, and Rice graduate students Yilun Li and William Sikkema. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science.

Source: Rice University

Published June 2016

Rate this article

[Wings: Graphene de-icer coating does double duty]

Very interesting, with information I can use
Interesting, with information I may use
Interesting, but not applicable to my operation
Not interesting or inaccurate

E-mail Address (required):


Type the number:

Copyright © 2016 by Nelson Publishing, Inc. All rights reserved. Reproduction Prohibited.
View our terms of use and privacy policy