A double-walled carbon nanotubes conducting wire prepared by dip-coating

Carbon nanotube (CNT) wires and cables with low electrical resistivity were synthesized through a wet chemical method (dip-coating) which is inspired from the commercial metal cable production. The double-walled carbon nanotube (DWCNT) wire is composed of a Polytetrafluoroethylene (PTFE) core, a DWCNT layer coated on PTFE surface and an exterior polyimide (PI) insulating layer. The results showed that the optimal concentration of DWCNT paste for dip-coating is between 1.8 wt. % and 2.0 wt. %. The direction of the DWCNTs in the conducting layer is substantially oriented along with the drawing direction. The coating layer is even and the thickness of DWCNT layer is around 90 μm. And the corresponding resistivity of obtained CNTs wire is about 8.2 × 10-6 Ωm. After treatment with iodine, its resistivity could be reduced by about 50%, reaches to 4.510-6 Ωm. More importantly, the coating of PI insulation layer results in DWCNT layer densification without reducing its electrical conductivity.