Internal field emission and conductivity relaxation in carbon nanofiber filled polymer system

Conducting polymer nanocomposites based on high density polyethylene (HDPE) and carbon nanofiber (CNF) were fabricated by melt compounding. The conductivity of the nanocomposites was found to follow the percolation behavior. Effect of electric field on the electrical conduction behavior of such composites was investigated. The results revealed two competing processes in the composite: internal field emission and electrical conduction relaxation. The former is dominant at lower filler concentrations or under low electric field, while the latter is pronounced under the application of strong electric field. Further, the relaxation time is nearly independent on the electric field strength but decreased with increasing temperature.