Percolation phenomena in nanocarbon composites

Abstract

Nanocarbon composites present a new type of nanomaterials consisted of electric conducting carbon nanoparticles and a non-conducting matrix. A typical example of such composites is a polymer matrix doped with carbon nanotubes (CNT). Due to a high aspect ratio of nanotubes insertion of very small quantity of CNT (on the level of 0.01%) promotes the percolation transition resulting in an enhancement of the conductivity of the material by 10–12 orders of magnitude. Another type of nanocarbon composite is a film consisted of partially reduced graphene oxide (GO) produced as a result of thermal reduction of graphite oxide material. Distinctive peculiarity of both types of nanocomposites relates to the dependence of the specific resistivity of the materials on the applied voltage. Such a behavior is caused by non-ideal contacts between neighboring carbon particles involving into the composite. The resistance of this contact depends drastically on the intra-contact field, which promotes the dependence of the material resistivity on the applied voltage. The model description of such a non-linear dependence has been presented. The calculation results are compared with both literature data and the measured data obtained for reduced GO thermally treated at various temperatures.