Universality in Microstructural Evolution of Deformed Polymer Melts as Revealed by Small-Angle Neutron Scattering and Molecular Dynamics Simulation

The viscoelastic properties of polymers are strongly influenced by the entanglement phenomenon. Historically, distinct theoretical models have been developed to understand the rheology of entangled and unentangled polymer melts. Using small-angle neutron scattering and nonequilibrium molecular dynamics simulations, we show that the microstructural evolutions of deformed entangled and unentangled polymer melts share a number of universal traits that cannot be comprehended within the classical theoretical framework. Our analysis suggests that interchain correlations play a fundamental role in nonlinear polymer melt rheology.