Electric field induced alignment of multiwalled carbon nanotubes in polymers and multiscale composites

Carbon fiber reinforced polymers (CFRPs) have a highly anisotropic electrical resistivity, which limits their use in electrical applications. In this contribution, an electric field was used to align multiwalled carbon nanotubes (MWCNTs) to create preferential conductive pathways within a nanocomposite and a multiscale composite in order to reduce their resistivity. Investigation on epoxy containing MWCNTs have shown that an electric field of 40 V mm−1 or higher applied for 2 h can lead to a reduction of the resistivity parallel to the field up to four orders of magnitude with only 0·01 wt-% loading. In the case of CFRPs reinforced with 0·01 and 0·1 wt-% of MWCNTs, we observed reductions of the through the thickness resistivity of 36 and 99% respectively, when an electric field of 60 V mm−1 was applied for 2 h during the fabrication of the samples.