Viscoelasticity near the gel-point: a molecular dynamics study

Vernon, D. C.; Plischke, Michael; Joos, Bela

Viscoelasticity near the gel-point: a molecular dynamics study

Authors

Vernon, D. C.

Plischke, Michael

Joos, Bela

Description

We report on extensive molecular dynamics simulations on systems of soft spheres of functionality f, i.e. particles that are capable of bonding irreversibly with a maximum of f other particles. These bonds are randomly distributed throughout the system and imposed with probability p. At a critical concentration of bonds, p_c approximately equal to 0.2488 for f=6, a gel is formed and the shear viscosity ηdiverges according to η~ (p_c-p)^{-s}. We find s is approximately 0.7 in agreement with some experiments and with a recent theoretical prediction based on Rouse dynamics of phantom chains. The diffusion constant decreases as the gel point is approached but does not display a well-defined power law.
4 pages, 4 figures