| 초록 |
The static and dynamic behavior of hard chains in disordered materials (or matrices) composed of fixed hard spheres is studied using discontinuous molecular dynamics simulations. The polymer chain shrinks at low matrix concentrations but swells back at higher matrix concentrations. In addition, the matrix induces entanglements in the fluid for very short chains, i.e., the diffusion coefficient, D, scales with the chain length, N, as D~N-2 for high matrix volume fractions, while in the absence of the matrix Zimm or Rouse behavior are observed for low and high solute concentrations. At high matrix concentrations the rotational relaxation time becomes very large but the translational diffusion is not affected significantly, which we show is due to trapping of a small number of molecules. Under these conditions the chains diffuse via a hopping mechanism. This decoupling between translational and rotational diffusions is also found in the glass transition, which implies that our model can serve as a simple model for the study of the glass transition phenomena. We also analyze the effect of the matrix structure on the polymer structure and diffusion. |
