Tailoring the Mechanical Properties of Polymer/Nanorod Nanocomposites through Polymer Functionalization

The rational design of polymers to improve nanorod dispersion and strengthen polymer-nanorod interfacial interactions is crucial for designing nanorod-filled polymer nanocomposites (PNCs). Herein, using coarse-grained molecular dynamics simulations, we studied the effect of polymer chain functionalization on the dispersion state of nanorods, the diffusion/relaxation of polymer matrix chains, and the mechanical properties of the corresponding PNCs. The simulation results showed that the nanorod dispersion state could be adjusted by functionalizing the polymer chain. Enhancing the functionalized bead-nanorod interactions or increasing the polymer chain functionalization degree improved the dispersion state of nanorods. The optimized nanorod dispersion state offered a much larger surface that could interact with the polymer matrix, resulting in an enhanced polymer-nanorod adsorption network. The simulation results indicated that the mechanical properties of the polymer nanocomposites (PNCs) improved progressively with an increase in interactions between functionalized beads and nanorods. However, the improvement was not monotonic with respect to the degree of functionalization, suggesting the existence of an optimal functionalization degree. The underlying mechanism of this was that a higher polymer chain functionalization degree optimized the polymer-nanorod adsorption network but hindered the polymer chain orientation during deformation. This work provides evidence theoretical guidance to design and fabricate nanorod-filled nanocomposites with tailored mechanical properties.