Graphene crystals are atom-thick planar sheets of sp2 carbon atoms connected together in hexagons, and forming a film of carbon atoms arranged like a honeycomb.
Since the graphite in pencils is simply a 3D structure comprising multiple stacked layers of graphene, graphene flakes are produced every time we put pencil to paper. Anyway, graphene was only isolated for the first time in 2004.
Graphene is one of the strongest, most elastic and stiffest material known to science. Graphene properties such as transparency, stiffness, strength, electrical and thermal conductivity can be combined with polymers with the aim of forming super-strong, thermally stable, optically transparent conducting polymers for interesting applications. Small amounts of exfoliated graphene sheets into the polymer improve polymerization thermal stability and stiffness.
In particular, new nanocomposites incorporating functionalized, exfoliated graphene sheets show extraordinary thermal and mechanical properties, similar or even better than functionalized single walled carbon nanotubes in polymers.
Graphene-polymer composites would be ideal to be used in different fields, such as lightweight gasoline tanks and plastic containers that keep food fresh for weeks. They could also be used to make lighter, more fuel-efficient aircraft and car parts, as well as stronger wind turbines, medical implants and sports equipment. What's more, they are good electrical conductors and could be used to make transparent conductive coatings for solar cells and displays.
In addition, the graphene sheets are able to block moisture and gases from penetrating the material, so that a monolayer graphene membrane has been used as a gas impermeable membrane for creating the world's thinnest balloon.
Finally, graphene oxide, obtained by graphite oxidation, has been used for the fabrication of a new type of paper. Graphene oxide is an insulator that could be used to realize membranes with controlled permeability, batteries, hybrid materials containing polymers, ceramics or metals, for applications in airplanes, cars, buildings and sporting good products.
