The equations needed to correctly interpret both AC and DC conductivity results of single wall carbon nanotube (SWNT) polymer composites and the scaling of these results onto a single master curve are presented. Brief discussions on the factors that determine the critical volume fraction (/ c ) and the percolation exponent (t) are also given. The results for a series of SWNT-polyimide composites are presented and the parameters obtained from fitting these results are discussed. The critical volume fraction for electrical percolation of the present composite was about 0.0005. Results obtained from previous work on SWNT (MWNT)-polymer composites and other percolation systems and the modeling (interpretation) of these results are also discussed and compared.

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Scaling functions, F + (ω/ω + c ) and F − (ω/ω − c ) for φ > φ c and φ < φ c , respectively, are derived from an equation for the complex conductivity of binary conductor-insulator composites. It is shown that the real and imaginary parts of F ± display most properties required for the percolation scaling functions. One difference is that, for ω/ω c < 1, ℜF − (ω/ω c ) has an ω-dependence of (1 + t)/t and not ω 2 as previously predicted, but never conclusively observed. Experimental results on a Graphite-Boron Nitride system are given which are in reasonable agreement with the ω (1+t)/t behaviour for ℜF − . Anomalies in the real dielectric constant just above φ c are also discussed.

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