Thermal Conductivity of Graphene
The thicker a graphene layer is, the more heat it can conduct per unit length. This is the result observed by researchers at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the National University of Singapore. Graphene is a modification of carbon with a two-dimensional structure in which the carbon atoms form a honeycomb-like pattern. In experiments and computer-aided simulations, it was possible to confirm that the thermal conductivity of graphene increases logarithmically with the thickness of the graphene layer.
Until now, physics has described thermal conductivity as an intrinsic material property that normally does not depend on size or shape. In the case of graphene, however, the thermal conductivity is apparently not a material-specific constant. The researchers assume that the two-dimensional structure and the rigid chemical bonds are responsible for the increase in thermal conductivity. In a non-equilibrium state, thermal vibrations can propagate almost without energy loss. This physical effect could be used in micro- and nano-electronics for more powerful and smaller components, for instance, for passive cooling of electronic components.
Graphene is chemically very stable and exhibits outstanding mechanical properties. Individual, single-layer graphene crystals were first produced in 2004. Recently, a research group of the University of Dublin introduced a new method with which graphite is subjected to such high shear loads that nanolayers of graphene form. According to the information, this process yields very high-quality graphene on an industrial scale.