On the effect of electric field application during the curing process on the electrical conductivity of single-walled carbon nanotubes-epoxy composites

Single-walled carbon nanotube (SWCNT)/epoxy composites were cured under external electric fields andthe influence of the processing parameters (electric field magnitude and frequency, SWCNT concentrationand curing temperature) on the electrical response of the system was evaluated. A mold for theelectric field application was designed and manufactured, allowing in situ measurements of the electricalresistivity of the composite, during and after the curing process. The resulting electrical propertiesrevealed a strong dependence on the processing parameters. By rising the curing temperature, the solidbulk resistivity was decreased by one order of magnitude. Further reduction was observed with electricfields, up to an additional order of magnitude. Such improvements can be related with the decrease inviscosity and improvement of interconnected-nanotube paths within the polymer matrix. The effect ofthe electric field on the rotation and interconnection of the SWCNTs was investigated using a classicalmechanics model based on the dielectrophoretic theory for the liquid state. The influence of internanotubedistances on the bulk electrical properties was calculated at different particle concentrations,using finite element models of the microstructure. This processing technique presents promisingresults for enhancing the electrical conductivity of polymer composites with carbon-based nanoparticles