Electrical conductive double-walled carbon nanotubes – Silica glass nanocomposites prepared by the sol–gel process and spark plasma sintering

The electrical conductivity of suspensions in liquid of several kinds of carbon nanotubes (CNTs) is measured. Raw and soft-functionalized double-walled carbon nanotubes (DWCNTs) appear to be the most promising for achieving a low electrical percolation threshold. A 0.35 vol.% DWCNTs–SiO2 nanocomposite is prepared by the sol–gel process and densified by spark plasma sintering. The obtained material presents a fairly good dispersion of DWCNTs and its electrical conductivity (10−4 S cm−1) is six orders of magnitude higher than that previously reported for 1 vol.% multi-walled CNTs–SiO2.