The effect of electric field parameters on the resistivity and induced percolation time of carbon black‐filled polystyrene composites

Abstract The present work examines the influence of externally applied alternating current (AC) electric fields on the formation of electrically conducting structures in carbon black/polystyrene (CB/PS) composites. It is shown that AC electric fields are capable of producing electrically conducting composites at filler concentrations substantially lower than the composite's percolation threshold by causing filler attraction and alignment into columnar structures with orientation normal to the electrode surface. The times required for the insulator‐to‐conductor transition (termed “percolation times”) in these CB/thermoplastic composites are measured as a function of important process parameters, such as applied voltage, electric field frequency, and filler concentration. The percolation times are shown to be inversely proportional to both the square root of the applied field intensity and to the power of 0.3 of the filler concentration, while they appear to be independent of AC field frequencies in the range 10 Hz to 10 KHz. These empirical scaling laws can be used as a guide for the selection of experimental conditions in future studies on electrified composites or for the selection of processing parameters in composites manufacturing. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers