Effect of nanotube waviness on the electrical conductivity of carbon nanotube-based composites

This paper reports the effect of nanotube waviness on the electrical conductivity of carbon nanotube-based composites using a percolation model. Wavy nanotubes are approximated by elongated polygons, and the current-carrying backbones of percolation clusters in the composite are identified by the direct electrifying algorithm. The tunneling resistance due to an insulating film of matrix material between crossing nanotubes is considered. Results of Monte Carlo simulations indicate that the electrical conductivity of composites with wavy nanotubes are lower than that of composites with straight nanotubes. The critical exponent of the power-law dependence of electrical conductivity on nanotube concentration decreases with increasing nanotube curl ratio. The conductivity exhibits an inverse power-law dependence on the curl ratio with a critical exponent in the range of 2.2-2.6. (c) 2007 Elsevier Ltd. All rights reserved.