Dynamic percolation as a tool for tailoring the electrical properties of carbon nanotube / polymer composites

The effect of dynamic percolation on the a.c. conductivity and permittivity of thermoplastic nanocomposites filled with 2.2 wt% of carbon nanotubes was studied. During isothermal annealing of the samples in the melt state a gradual and large increase of conductivity was evidenced with time. The profile of permittivity versus annealing time unexpectedly exhibited 2 maxima. This surprising feature was further studied and understood in terms of the action of two possible driving forces for dynamic percolation. The first one was attributed to the local polymer chain relaxation. The second mechanism was ascribed to the motion of the conducting filler, similar to a diffusion process.