Controlling the electrical conductive network formation in nanorod filled polymer nanocomposites by tuning nanorod stiffness

Abstract

In this work, by employing a coarse-grained molecular dynamics simulation, we have investigated the effect of the nanorod (NR) stiffness on the relationship between the NR microstructure and the conductive probability of NR filled polymer nanocomposites (PNCs) under the quiescent state and under the shear field. The conductive probability of PNCs is gradually enhanced with the increase of NR stiffness in the quiescent state; however, it first increases and then decreases under the shear field. As a result, the largest conductive probability appears at moderate NR stiffness, which results from the competition between the improved effective aspect ratio of the NR and the breakage of the conductive network.Meanwhile, compared with in the quiescent state, under the shear field the decrease or the increase of the conductive probability depends on the NR stiffness. At low NR stiffness, the increase of the effective aspect ratio of NR enhances the conductive probability, while at high NR stiffness, the breakage of the conductive network reduces the conductive probability. For flexible NRs, the conductive probability first increases and then decreases with increasing the shear rate. The maximum effective aspect ratio of NRs appears at the moderate shear rate, which is consistent with the conductive probability. In summary, this work presents some further understanding about how NR stiffness affects the electric conductive properties of PNCs under the shear field.

Percolation Threshold and Depression in Properties of Polymer Nanocomposites

“…Despite the different changes in the material during the occurrence and increase of the percolation state, electrical conductivity is one of the most characteristic properties that can be observed and measured when adding conductive nanoparticles to a dielectric matrix. This happens because the incorporation of conductive nanoparticles increases the probabilities of conductive path formation 15 until it reaches a critical value and the nanocomposite changes from dielectric to dissipative or conductive, which is also indicated as the percolation threshold [16][17][18][19][20][21][22][23][24] . Moreover, the state of percolation in nanocomposites also presents changes on mechanical properties, which can be enhanced with low volume fractions of nanoparticles 25 or present discontinuities, caused by local perturbations on polymer chains, leading to a degradation mechanism of mechanical properties 8 .…”

Percolation analysis of the electrical conductive network in a polymer nanocomposite by nanorod functionalization

“…Thus, the reduced LJ units s and 3 are set to be unity, which means that all calculated quantities are dimensionless. Following our previous works, [37][38][39] rst all the polymer chains and NRs are put into a large box. Then, the NPT ensemble is used to compress the system for 10 000s where s is the reduce time unit.…”