Graphene composite may keep wings ice-free

January 25, 2016
Rice University scientists embedded graphene nanoribbon-infused epoxy in a section of helicopter blade to test its ability to remove ice through Joule heating. Credit: Tour Group/Rice University

A thin coating of graphene nanoribbons in epoxy developed at Rice University has proven effective at melting ice on a helicopter blade.

The coating by the Rice lab of chemist James Tour may be an effective real-time de-icer for aircraft, , transmission lines and other surfaces exposed to winter weather, according to a new paper in the American Chemical Society journal ACS Applied Materials and Interfaces.

In tests, the lab melted centimeter-thick ice from a static helicopter rotor blade in a minus-4-degree Fahrenheit environment. When a small voltage was applied, the coating delivered electrothermal heat - called Joule heating - to the surface, which melted the ice.

The nanoribbons produced commercially by unzipping nanotubes, a process also invented at Rice, are highly conductive. Rather than trying to produce large sheets of expensive graphene, the lab determined years ago that nanoribbons in composites would interconnect and conduct electricity across the material with much lower loadings than traditionally needed.

Previous experiments showed how the nanoribbons in films could be used to de-ice radar domes and even glass, since the films can be transparent to the eye.

Lab tests at Rice University on a section of a helicopter rotor chilled to minus-4 degrees Fahrenheit show that a thin coat of nanoribbon-infused epoxy can be used as a de-icer. The composite, imbedded between an abrasion shield and the blade in the sample above, heated when electricity was applied, melting the ice. The material may be suitable for keeping aircraft, wind turbines and transmission lines free of ice. Credit: Tour Group/Rice University

"Applying this composite to wings could save time and money at airports where the glycol-based chemicals now used to de-ice aircraft are also an environmental concern," Tour said.

In Rice's lab tests, nanoribbons were no more than 5 percent of the composite. The researchers led by Rice graduate student Abdul-Rahman Raji spread a thin coat of the composite on a segment of rotor blade supplied by a helicopter manufacturer; they then replaced the thermally conductive nickel abrasion sleeve used as a leading edge on . They were able to heat the composite to more than 200 degrees Fahrenheit.

For wings or blades in motion, the thin layer of water that forms first between the heated composite and the surface should be enough to loosen ice and allow it to fall off without having to melt completely, Tour said.

The lab reported that the remained robust in temperatures up to nearly 600 degrees Fahrenheit.

As a bonus, Tour said, the coating may also help protect aircraft from lightning strikes and provide an extra layer of electromagnetic shielding.

Explore further: Researchers create sub-10-nanometer graphene nanoribbon patterns

More information: Abdul-Rahman O. Raji et al. Composites of Graphene Nanoribbon Stacks and Epoxy for Joule Heating and Deicing of Surfaces, ACS Applied Materials & Interfaces (2016). DOI: 10.1021/acsami.5b11131

Related Stories

Graphene nanoribbons an ice-melting coat for radar

December 16, 2013

(Phys.org) —Ribbons of ultrathin graphene combined with polyurethane paint meant for cars is just right for deicing sensitive military radar domes, according to scientists at Rice University.

Smart anti-icing system for rotor blades

December 1, 2014

In very cold climate zones, the wind can blow with tremendous force. But wind turbines have rarely been built in these regions up to now. The risk of ice formation on the rotor blades is just too high. But now, an energy-efficient ...

Toward roads that de-ice themselves

December 16, 2015

As winter approaches, stores, cities and homeowners are stocking up on salt, gravel and sand in anticipation of slippery roads. But this annual ritual in colder climates could soon become unnecessary. Researchers report in ...

Recommended for you

Neuromorphic computing mimics important brain feature

August 18, 2016

(Phys.org)—When you hear a sound, only some of the neurons in the auditory cortex of your brain are activated. This is because every auditory neuron is tuned to a certain range of sound, so that each neuron is more sensitive ...

'Artificial atom' created in graphene

August 22, 2016

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom - for this reason, such electron ...

Picoscale precision though ultrathin film piezoelectricity

August 10, 2016

Piezoelectricity (aka the piezoelectric effect) occurs within certain materials – crystals (notably quartz), some ceramics, bone, DNA, and a number of proteins – when the application of mechanical stress or vibration ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

ab3a
not rated yet Jan 25, 2016
"As a bonus, Tour said, the coating may also help protect aircraft from lightning strikes and provide an extra layer of electromagnetic shielding."

Really? I figure a lightning strike might very well delaminate the composite. Lightning has a very strong surface effect due to the massive currents involved. Temperatures will rise ridiculously high as the various components are ionized.

This is speculation. I'll wait for lightning tests by the FAA before I believe it. (Yes, as part of aircraft certification, the FAA insists that a very large Electrical discharge be done to simulate lightning)
Zurg
not rated yet Jan 26, 2016
Just wondering if an airfoil leading edge at 200 degrees affects a wing's aerodynamic qualities? Obviously a research next step...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.