Nonequilibrium molecular dynamics of complex fluids near the gel point

Abstract

We have carried out nonequilibrium molecular dynamics simulations of a system of crosslinked particles under shear flow conditions. As the fraction of crosslinks $p$ is increased the system approaches a gel point at which the shear viscosity $η$ and the first and second normal stress coefficients $Ψ_1$ and $Ψ_2$ diverge. All three quantities seem to diverge with a power law form: $η\sim ε^{-s}$, $Ψ_{1,2}\simε^{-λ}$ where $ε=p_c-p$ and $s\approx 0.7$ and $λ\approx 3.15$ in three dimensions and $s\approx 2.0$ and $λ\approx 6.0$ in two dimensions.