초록 |
Thin polymer film embedded with nanoparticles (NPs) received attention due to its applicability in various fields. Because the diffusion of NPs in film may enhance the patterning stability and wetting behavior, the NP transport has been an issue of interest. For example, AuPS NPs diffusion determines the morphology evolution kinetics in PMMA films. It still remains unclear at a molecular level how NPs would diffuse in films. In this study, we investigate the diffusion mechanism of NPs in freestanding thin polymer films by employing molecular dynamics simulations and generic coarse-grained models.We find that a spatial distribution of NPs depends on the size and intermolecular interactions of NPs. NPs, of a large diameter with attractive intermolecular interactions, reside at the film center and diffuse slowly. Small NPs, on the other hand, stay at the interfacial region and diffuse quickly. This spatial dependence of NP diffusion might relate to the glass transition of the film. |