Dissipative Particle Dynamics (DPD) Simulation to understand the Nanoparticle Dispersion and Aggregation behavior in Polymer Nanocomposites

Polymer nanocomposites, i.e. polymer matrix with nanoparticles of variable amounts and types, possess a broad range of applications. In particular, polymeric systems such as natural rubber used in car and truck tires require the addition of suitable additives for the enhancement of numerous properties, including reinforcement and durability. The behavior of such fillers, (carbon black, silica, and metal oxides and some combination thereof), and their influence on nanocomposite effectiveness, depends on the filler structure, the interaction between filler-polymer as well as the processing history. In this research, we perform Dissipative Particle Dynamics (DPD) simulation of these blends, varying polymer-polymer interaction energy to study the dispersion and aggregation mechanism of fillers. Our results demonstrate the role of concentration on the clustering of fillers and methods to quantify the filler percolation threshold and mesh size. Additionally, the effect of such agglomerates on the structural and dynamical properties of the nanocomposites, measured via the radial distribution, mean square displacement, and autocorrelation function are explored. The simulation results are also validated against small-angle x-ray scattering data.