Frequency dependence of effective permittivity of carbon nanotube composites

Dependence of the permittivity of single-walled and multiwalled carbon nanotube composites on frequency and concentration was investigated experimentally using the coaxial air-line method over 0.1-10 GHz. The results are in good agreement with that obtained using the impedance method. It is found that scaling law based on the percolation theory provides a good description of the frequency dependence of measured permittivity in carbon nanotube composites. Parameters of the scaling law and deviations from the percolation theory are also discussed. (C) 2007 American Institute of Physics.