Thermophoresis of Graphene Plates

Thermophoresis of graphene plates in an air medium is discussed within the framework of a molecular-kinetic approach. Its rate is found to be independent of the plate area and the aspect ratio of a rectangular graphene. It does depend on the plate orientation in space, which is controlled by the principle of least resistance. The dependence is expressed via a geometrical parameter σ, whose limiting values within the variation interval are found to be 0.46 and 0.65. A solution of the Euler problem on the Brownian rotation of a plate around its center of mass as a result of collisions of molecules in the temperature gradient field allowed us to obtain for the graphene plates a statistical average of σ =0.5. This value turned out to be the same as the one for spherical nanoparticles, for which rotations are irrelevant.