Molecular Dynamics Study on Polymer Nanocomposite on a Substrate with Different Nanoparticle Architecture

Here, the effects of nanoparticle (NP) architecture are investigated on polymer mobility in polymer films on a substrate. Our findings reveal that lower interaction strength between polymer and NP facilitates greater polymer mobility, reflected in increased diffusion coefficient values, while stronger interactions result in reduced diffusivity. Due to the asymmetric structure of tetrapod NPs, the polymer motion is faster compared to spherical and dumbbell NPs, respectively by creating more free volume around the NPs. This has been substantiated by the stronger local ordering of polymer chains around spherical NPs, where the simple geometry promotes tighter packing. In contrast, the complex architecture of tetrapod NPs reduces local ordering, introduces geometric frustration in the surrounding polymer matrix, leading to less efficient packing and more free volume, which enhances polymer mobility. Additionally, films with holes are healed faster in a polymer nanocomposite with tetrapod NPs than the other architecture.