Coarse-grained models of Poly(ethylene oxide) oligomer-grafted nanoparticles are established by matching their structural distribution functions to atomistic simulation data. Coarse-grained force fields for bulk oligomer chains show excellent transferability with respect to chain lengths and temperature, but structure and dynamics of grafted nanoparticles systems exhibit a strong dependence on the core-core interactions. This leads to poor transferability of the core potential to conditions different from the state point at which the potential was optimized. Remarkably, coarse-graining of grafted nanoparticles can either accelerate or slowdown the core motions, depending on the length of the grafted chains. This stands in sharp contrast to linear polymer systems, for which coarse-graining always accelerates the dynamics. Diffusivity data suggest that the grafting topology is one cause of slower motions of the cores for short-chain oligomer-grafted nanoparticles; an estimation based on transition-state theory shows the coarse-grained core-core potential also has a slowing-down effect on the NOHMs motions; both effects diminish as grafted chains become longer.
Begin Flash full motion video, or Flash lower bandwidth video. (Or, right-click to download the 3gp file.)
Begin QuickTime full motion movie or Quicktime lower bandwidth movie.
(Or, right-click to download the lower bandwidth movie.)
(Or, right-click to download the podcast.)
Begin streaming RealMedia. (Or, right-click to download the audio file.)
To begin viewing slides, click on the first slide below. (Or, view as pdf.)