September 29, 2008 – Researchers at the U. of Texas at Austin have created a new “graphene-based” material that they claim helps solve the structure of graphite oxide, and could lead to other potential discoveries of graphene, which has applications in nanoelectronics, energy storage and production, and transportation such as airplanes and cars.

Nanomaterial graphene is a lightweight material with exceptional mechanical properties; it also conducts heat better than any other material, and has charge carriers moving through it at a significant fraction of the speed of light. Just an atom thick, graphene consists of a “chickenwire” (or honeycomb) bonding arrangement of carbon atoms — also known as a single layer of graphite.

However, the detailed chemical structure of graphite oxide (GO), a layered material prepared from graphite that was a precursor to chemically modified graphenes, has not been previously resolved because of the pseudo-random chemical functionalization of each layer, as well as variations in exact composition, the scientists note in their paper appearing in the Sept. 26 issue of the journal Science.

Mechanical Engineering Professor Rod Ruoff and his co-authors have, for the first time, prepared carbon-13 labeled graphite. They did this by first making graphite that had every “normal” carbon atom having the isotope carbon-12, which is magnetically inactive, replaced with carbon-13, which is magnetically active. They then converted that to carbon-13 labeled graphite oxide and used solid-state nuclear magnetic resonance to discern the detailed chemical structure of graphite oxide.

“As a result of our work it will now be possible for scientists and engineers to create different types of graphene and to study such graphene-based materials with solid-state nuclear magnetic resonance to obtain their detailed chemical structure,” Ruoff says. “This includes situations such as where the graphene is mixed with a polymer and chemically bonded at critical locations to make remarkable polymer matrix composites; or embedded in glass or ceramic materials; or used in nanoelectronic components; or mixed with an electrolyte to provide superior supercapacitor or battery performance. If we don’t know the chemistry in detail, we won’t be able to optimize properties.”

Mechanical Engineering Professor Rod Ruoff, U. of Texas, Austin. (Source: UT/Austin)

Graphene-based materials are a focus area of research at the university because they are expected to have applications for ultra-strong yet lightweight materials that could be used in automobiles and airplanes to improve fuel efficiency, the blades of wind turbines for improved generation of electrical power, as critical components in nanoelectronics that could have blazing speeds but very low power consumption, for electrical energy storage in batteries and supercapacitors to enable renewable energy production at a large scale and in transparent conductive films that will be used in solar cells and image display technology. In almost every application, sensitive chemical interactions with surrounding materials will play a central role in understanding and optimizing performance.