Controlling the conductive network formation of polymer nanocomposites filled with nanorods through the electric field

Facilitating the electric field to fabricate high performance polymer nanocomposites (PNCs) is always a great and promising strategy. In this work, the effect of the electric field on the conductive property of the PNCs is investigated by adopting coarse-grained molecular dynamics simulation. The translational and rotational diffusion of the nanorod gradually decreases with the increase of the nanorod aspect ratio; however, it is nearly independent of the nanorod volume fraction. Under the electric field, it exhibits a limited decrease, but more anisotropy of the translational diffusion of the nanorod. Meanwhile, the nanorods can not experience the random rotation, which is attributed to the electrostatic force. In addition, on one hand, the electrostatic force exerting on the nanorods induces the nanorod orientation, leading to the decrease of the homogeneous conductive probability; however, the electrostatic interaction induces the connection of the nanorod, resulting in the increase of the homogeneous conductive probability. Additionally, the directional conductive probability parallel to the electric field direction increases; however, the directional conductive probability perpendicular to the electric field direction shows a continuous decrease. Considering these two effects, the decrease or the increase of the homogeneous conductivity probability depends on the competition between the electrostatic force and the electrostatic interaction. The relationship among the anisotropy of the conductive probability, the nanorod volume fraction, the electrostatic force and the electrostatic interaction can be described quantitatively by an empirical formula. Another empirical formula is adopted to quantitatively describe the relationship among the percolation threshold, the electrostatic force and the electrostatic interaction. Meanwhile, the evolution process of the conductivity network structure is studied with or without the electric field. In summary, this work quantitatively describes the effect of the electric field on the conductive property of the PNCs, which can provide some useful guidances to design and fabricate PNCs with excellent conductivity properties by taking advantage of the external electric field.