Molecular Dynamics Simulation Of Electrical Conductivity Of Elastomer Composites Filled With Hybrid Fillers

Conductive elastomer composites are widely used,but their conductivity depends on the composition of the conductive network,the stability of the conductive network plays an important role in the conductive performance of conductive elastomer composites,and the structure of the conductive network is very easily affected,this limits the application of conductive elastomer composites,so we formed more stable conductive network by adding two kinds of fillers to solve this problem In this study.The molecular dynamics simulation of the coarse-grained model was used to study the conducting performance of nanospheres and nanorods in the hybrid fillers elastomer and its mechanism,mainly for the following two aspects were studied:(1)The influence of conductive nanospheres and conductive nanorods on the conductive network of elastomer nanocomposites.The percolation threshold of the system decreases as the proportion of nanorods in the filler volume increases,mainly because nanorods are more conducive to the formation of conductive networks.Then,the factors influencing the synergistic effect of the system were studied.We found that the synergistic and antagonistic effect of the system was related to the conductive property between the two fillers,namely the tunneling effect.When the tunneling effect changed from weak to strong,the system would change from antagonistic effect to synergistic effect.By applying shear field,the direct aggregation structures in the conductive network increase,and the conductive network is destroyed due to the orientation of the pure rod system,and the percolation threshold increases.The percolation threshold of other systems did not increase,and the decrease range of percolation threshold increased with the increase of the proportion of nanosphere fillers.By studying the effect of shear rate on the effective volume fraction of nanospheres in a conductive network,it is found that the main reason is that the nanospheres protect the conductive network perpendicular to shear direction.(2)The influence of non-conductive nanospheres and conductive nanorods on the conductive network of elastomer nanocomposites.Firstly,the influence of the size of non-conductive nanospheres on the conductivity probability was studied.In the nanospheres with the same diameter,the conductivity probability increased with the increase of the volume fraction of the nanospheres.With the increase of nanospheres diameter,composite conductive probability decreases,The effective volume of nanorods was studied.It was found that the addition of nanospheres first eliminated the dominance of the volume,and then the structure of the conductive network was optimized.Then the interaction between nanosphere-nanorods is studied,when the interaction is 2.0 or 3.0,the nanorods and nanospheres dispersed evenly,unfavorable to nanorods'connection,conductive network is difficult to form.Under the shear filed,when the volume fraction of nanosphere is small,the excluded volume of nanospheres can protect the conductive network on the perpendicular to the direction of shear;When the volume fraction of the nanospheres increase to a certain value,the conductive network is destroyed.