The fabrication and electrical properties of carbon nanofibre-polystyrene composites

Carbon nanofibre-polystyrene (PS) composites were fabricated by ultrasonic dispersion in a solution followed by spraying to cast films. These films were then hot-pressed to form thicker structures. Direct current conductivity measurement results show that the conductivity of the composite reaches 2.6 x 10(-5) S m(-1) at 3 wt% carbon nanofibre loading, which is an increase of ten orders of magnitude over the pure PS matrix, indicating that the composite is electrically conductive at a very low nanofibre loading. The dielectric properties of carbon nanofibre-PS composites were investigated at room temperature within the Ku-band (frequency range: 12.4-18 GHz). The results reveal that the dielectric constants of the composites are slightly dependent on the frequency but increase rapidly with increasing carbon nanofibre loading in the composite. The experimental data show that the dielectric constant of carbon nanofibre-PS composite can reach more than 80 at a frequency of 15 GHz.