Super-light graphene and ceramic metamaterial possesses high strength, other attributes

August 10, 2017 by Emil Venere, Purdue University
A new composite material combines ultra-lightweight with flame-resistance, super-elasticity and other attributes that could make it ideal for various applications. Here, the material is viewed with a scanning electron microscope, while its flame resistance is put to the test. Credit: Purdue University photo

A new featherweight, flame-resistant and super-elastic "metamaterial" has been shown to combine high strength with electrical conductivity and thermal insulation, suggesting potential applications from buildings to aerospace.

The composite combines nanolayers of a ceramic called aluminum oxide with , which is an extremely thin sheet of carbon. Although both the ceramic and graphene are brittle, the new metamaterial has a honeycomb microstructure that provides super-elasticity and structural robustness. Metamaterials are engineered with features, patterns or elements on the scale of nanometers, or billionths of a meter, providing new properties for various potential applications.

Graphene would ordinarily degrade when exposed to high temperature, but the ceramic imparts high heat tolerance and flame-resistance, properties that might be useful as a heat shield for aircraft. The light weight, high-strength and shock-absorbing properties could make the composite a good substrate material for flexible electronic devices and "large strain sensors." Because it has high and yet is an excellent thermal insulator, it might be used as a flame-retardant, thermally insulating coating, as well as sensors and devices that convert heat into electricity, said Gary Cheng, an associate professor in the School of Industrial Engineering at Purdue University.

"This material is lighter than a feather," he said. "The density is really low. It has a very high strength-to-weight ratio."

Findings were detailed in a research paper published on May 29 in the journal Advanced Materials. The paper was a collaboration between Purdue, Lanzhou University and the Harbin Institute of Technology, both in China, and the U.S. Air Force Research Laboratory. A research highlight about the work appeared in the journal Nature Research Materials.

"The outstanding properties of today's ceramic-based components have been used to enable many multifunctional applications, including thermal protective skins, intelligent sensors, electromagnetic wave absorption and anticorrosion coatings," Cheng said.

Credit: Purdue University

However, ceramic-based have several fundamental bottlenecks that prevent their ubiquitous use as functional or structural elements.

"Here, we report a multifunctional ceramic-graphene metamaterial with microstructure-derived super-elasticity and structural robustness," Cheng said. "We achieved this by designing a hierarchical honeycomb microstructure assembled with multi-nanolayer cellular walls serving as basic elastic units. This metamaterial demonstrates a sequence of multifunctional properties simultaneously that have not been reported for ceramics and ceramics–matrix–composite structures."

The composite material is made of interconnected cells of graphene sandwiched between ceramic layers. The graphene scaffold, referred to as an aerogel, is chemically bonded with ceramic layers using a process called atomic layer deposition.

"We carefully control the geometry of this graphene aerogel," he said. "And then we deposit very thin layers of the ceramic. The mechanical property of this aerogel is multifunctional, which is very important. This work has the potential of making graphene a more functional material."

The process might be scaled up for industrial manufacturing, he said.

Future work will include research to enhance the material's properties, possibly by changing its crystalline structure, scaling up the process for manufacturing and controlling the microstructure to tune material properties.

Explore further: Guinness World Records names graphene aerogel as world's least dense 3-D printed structure

More information: Qiangqiang Zhang et al. Flyweight, Superelastic, Electrically Conductive, and Flame-Retardant 3D Multi-Nanolayer Graphene/Ceramic Metamaterial, Advanced Materials (2017). DOI: 10.1002/adma.201605506

Adam Brotchie. Metamaterials: Graphene makes ceramics multifunctional, Nature Reviews Materials (2017). DOI: 10.1038/natrevmats.2017.44

Related Stories

Flying start for world's first graphene-enhanced aircraft

November 28, 2016

Prospero, the first model aircraft to incorporate a graphene skinned wing, was successfully flown at the Farnborough International Air Show in the UK earlier this year. The flight sets an example of how graphene might be ...

Mimicking nature's cellular architectures via 3-D printing

February 6, 2017

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being compressed. The plant's hardiness comes from a combination of its ...

Recommended for you

Flexible color displays with microfluidics

August 16, 2018

A new study published on Microsystems and Nanoengineering by Kazuhiro Kobayashi and Hiroaki Onoe details the development of a flexible and reflective multicolor display system that does not require continued energy supply ...

Twisted electronics open the door to tunable 2-D materials

August 16, 2018

Two-dimensional (2-D) materials such as graphene have unique electronic, magnetic, optical, and mechanical properties that promise to drive innovation in areas from electronics to energy to materials to medicine. Columbia ...

Novel sensors could enable smarter textiles

August 16, 2018

A team of engineers at the University of Delaware is developing next-generation smart textiles by creating flexible carbon nanotube composite coatings on a wide range of fibers, including cotton, nylon and wool. Their discovery ...

Scientists discover why silver clusters emit light

August 16, 2018

Clusters of silver atoms captured in zeolites, a porous material with small channels and voids, have remarkable light-emitting properties. They can be used for more efficient lighting applications as a substitute for LED ...

0 comments

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.