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Advanced Materials

Very Low Conductivity Threshold in Bulk Isotropic Single-Walled Carbon Nanotube–Epoxy Composites


  • We gratefully acknowledge useful conversations about percolation with Brooks Harris, Tom Lubensky, and Brian DiDonna. This work is supported by grants from NSF (MRSEC DMR-0079909 (A. G. Y., J. M. K.)) and DMR-0203378 (A. G. Y.)), NASA (NAG8 2172 (A. G. Y.)), and DARPA/ONR (N00015-01-1-0831 (J. M. K.)).


Electrical conductivity of single-walled carbon nanotube (SWNT)–epoxy composites (see Figure) is investigated as a function of SWNT concentration, mean length, and aggregation. The composites exhibit a percolation-like conductivity with threshold volume fractions as low as 5.2 × 10–5. These low thresholds are attributed to continuous nanotube chains that form in the semi-dilute concentration regime; higher thresholds result when aggregation is inhibited.

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