Tuning the insulator to conductor transition in a multiwalled carbon nanotubes/epoxy composite at substatistical percolation threshold

A fine tuning of the electrical conductivity from insulator to conductor behavior has been obtained for a multiwalled carbon nanotubes epoxy composite at a fixed substatistical percolation threshold content by varying the organization of the nanotubes network. A multiscale characterization has been carried out by transmission optical microscopy technique and small angle x-ray analysis that revealed a two level structure characterized by different topological arrangements for the micron sized clusters and nanosized isolated bundles, respectively. A picture of the multidimensional organization of the nanotubes network has been proposed to account for the observed transition modulation.