The influence of single-walled carbon nanotube structure on the electromagnetic interference shielding efficiency of its epoxy composites

Three types of single-walled carbon nanotube (SWCNT) homogeneous epoxy composites with different SWCNT loadings (0.01-15%) have been evaluated for electromagnetic interference (EMI) shielding effectiveness (SE) in the X-band range (8.2-12.4 GHz). The effect of the SWCNT structure including both the SWCNT aspect ratio and wall integrity, on the EMI SE have been studied and are found to correlate well with the conductivity and percolation results for these composites. The composites show very low conductivity thresholds (e.g. 0.062%). A 20-30 dB EMI SE has been obtained in the X-band range for 15% SWCNT loading, indicating that the composites can be used as effective lightweight EMI shielding materials. Furthermore, their EMI performance to radio frequencies is found to correspond well with their permittivity data. (c) 2007 Published by Elsevier Ltd.