DEVELOPMENTS TOWARD SIMULATION OF ENTANGLED POLYMER MELTS BY DISSIPATIVE PARTICLE DYNAMICS (DPD)

A segmental repulsion force is developed to reduce the frequency of artificial chain segment crossing events in DPD simulations of the dynamics of polymer melts. The scaling of viscosity and center of mass diffusion coefficients with chain length show transitions in scaling exponents at a critical entanglement chain length. Above the entanglement chain length, the scaling exponent for the diffusion coefficient is close to the experimental value of -2, but the scaling exponent for viscosity is close to +2, which is smaller than the experimental value of +3.4. Without segmental repulsion forces, chain segment crossings occur freely, and the scaling of both diffusion coefficient and viscosity follow the Rouse model for all chain lengths.