DC and AC Conductivity of Carbon Nanotubes−Polyepoxy Composites

Sophie Barrau (1) , Philippe Demont (1) , Alain Peigney (1) , Christophe Laurent (1) , Colette Lacabanne (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

The dc and ac conductivities of carbon nanotubes−polyepoxy composites have been investigated from 20 to 110 °C in the frequency range 10-2−106 Hz as a function of the conductive weight fraction p ranging from 0.04 to 2.5 wt %. The frequency dependence of the measured conductivity obeys the universal dynamic response (UDR): a dc plateau followed, above a critical frequency ωc, by the ωs power law with exponent s 0.6−1. The dc conductivity follows a percolation scaling law: σdc (p − pc)t with pc = 0.3 wt % and t = 1.4−1.8, according to the temperature. σdc reached 10-4 S/cm for 2.5 wt % CNTs content and increases with increasing temperature. Considering a biased random walk in three dimensions approach, we may explain the scaling law of ωc with p and its proportionality to σdc. The universality of ac conduction in carbon nanotubes−polymer composites is examined by the construction of master curves.

Mots clés: Electrical Conductivity; Carbon Nanotubes; Epoxy; Composites

Domaines: Matériaux; Matériaux

Sophie Barrau, Philippe Demont, Alain Peigney, Christophe Laurent, Colette Lacabanne. DC and AC Conductivity of Carbon Nanotubes−Polyepoxy Composites. Macromolecules, 2003, vol. 36, pp. 5187-5194. ⟨10.1021/ma021263b⟩. ⟨hal-00920407⟩