Controlling the dispersion and orientation of nanorods in polymer melt under shear: coarse-grained molecular dynamics...

Incorporation of nanorods (NRs) into a polymer matrix can greatly enhance the material properties, but the aggregation of NRs prevents the full realization of their potential. Using coarse-grained molecular dynamics simulation with the dissipative particle dynamics thermostat, we have systematically examined how key material and processing parameters, such as aspect ratio, particle diameter, rigidity and concentration of NR, polymer chain length, and shear rate can influence the placement and orientation of the self-aggregating NRs in a model polymer melt under shear. When compared with nanoparticles (NPs), the NRs tend to aggregate more severely even under strong shear flow. To improve the dispersion of NRs within the polymer matrix under a given flow condition, we incorporated additional NPs with selective interactions into polymer/NR composites, demonstrating that the current mesoscale simulation study offers insights on how to control the dispersion and orientation of NRs in polymer under shear flow.