| dc.description.abstract | Polymer-inorganic nanoparticle composites exhibit materials properties superior to their constituents and thereby enable a wide range of applications. However, many scientific and technical issues remain unaddressed, especially the dynamic behaviors of the composites and their correlation with the microscopic structures, which are practically important due to their influences on materials processing and production. In this research, we aim to address the issues evolving around the dynamics and structure-dynamics correlations via experiments and simulations. Experimentally, by in-situ reduction of metal salts (Palladium (II) acetylacetonate) dispersed in a polymer matrix, we are able to prepare nanocomposites of palladium (Pd) nanoparticles embedded in the polymer, poly(2-vinyl pyridine) (P2VP), featured with different Pd loadings and polymer molecular weights (MWs). By exploiting differential scanning calorimetry, rheology, and small- and wide-angle X-ray scattering, we explore how variations in Pd loadings and P2VP MWs (below and above the entanglement MW) affect the dynamics and structure-dynamics correlations of the composites at temperatures across the glass transition temperature. Computationally, molecular-dynamics simulations are employed to examine the structures and molecular motions of the composite systems under a variety of conditions, from which the radius of gyration of the polymer chains, glass transition temperature and the mean-square displacement of the polymer chains are calculated. Integrating the results from the simulations and experiments, we expect to develop insights on how the structures and dynamics of the composites correlate iii with each other and how these correlations in the microscopic scale dictate materials properties in the macroscopic scale. In this study, it was determined that Pd NPs were prepared by the reduction reaction, and the sample morphology was analyzed by SAXS, which was in line with the expected model and dispersion. And in the simulation, adding the attraction interaction in the systems would have a dispersion that was consistent with the experiment. Then using DSC to analyze thermal properties shows that with increasing the molecular weight and Pd(acac)2 concentration, Tg will also increase. Last, using a rheometer to analyze the motion behavior, with increasing the concentrations of the Pd(acac)2, the motion become slow. Finally, adding an attractive interaction in the simulation will have a consistent trend with the experiment, and these properties are due to the attractive interaction between polymers and nanoparticles in the samples | en_US |