Nonlinear resistance of polymer composites with carbon nanotube additives in the percolation state

The electrical properties of a polymer composite with carbon nanotube additives have been analyzed. The state of the system near the percolation threshold, when charge is transferred along a single percolation path, has been considered. For this state, the current-voltage characteristics of a percolation chain made up of carbon nanotubes have been calculated under the assumption that the contact resistance between neighboring nanotubes is much higher than the intrinsic resistance of the nanotubes. According to recent data, the distance between neighboring (contacting) nanotubes has been assumed to be randomly distributed. It has been shown that, under the given conditions, the current-voltage characteristic is essentially nonlinear. This indicates the nonohmic conductivity of the composites. The dependence of the current-voltage characteristic on the spread of the contact distribution over distances has been discussed.