<i>A priori</i> Determination of the Extensional Viscosity of Polydisperse Linear Polymer Melts

Compared to coarse grained MD, the COMOFLO algorithm is 100,000 times faster. The steady-state extensional viscosity function is calculated in a parameter free completely a priori manner as previously done for shear (Parameter Free Prediction of Rheological Properties of Homopolymer Melts by Dynamic Monte Carlo Simulation, Dorgan et.al., Macromolecules, (2012) DOI: 10.1021/ma301307d). The algorithm captures molecular details of extensional flow in three dimensions for entangled polymer melts of arbitrary molecular weight distribution across multiple flow regimes from the correct low deformation limit, through the strain-hardening regime, to the high deformation rate strain softening region. Comprehensive a priori shear rheology of polydisperse systems was established earlier (Finding the Missing Physics: Mapping Polydispersity into Lattice-Based Simulations. Rorrer & Dorgan, Macromolecules, 2014, DOI: 10.1021/ma5001207 ). The ability to predict steady shear and elongational rheology for linear polymer melts of arbitrary molecular weight distribution can be considered a solved problem.