Molecular-based approaches for understanding and tailoring structure-property-processing relations in materials, based on the fundamental principles of quantum and statistical mechanics, have gained ground in academic research and industrial practice.  They have been greatly aided by an unprecedented growth in computer power, but also by new, efficient  theoretical and computational methods and algorithms.   The broad spectra of length and time scales governing structure and dynamics in real-life materials have demanded the advancement of multiscale modeling strategies, involving several levels of representation, to bridge atomistic constitution and interactions with macroscopic properties. 

In this talk we will discuss three examples of molecular modeling of structure-property relations in polymeric materials: (a) prediction of linear and nonlinear rheological properties of polymer melts through hybrid particle-field mesoscopic simulations employing slip-springs to represent entanglements and parameterized on the basis of atomistic calculations; (b) tracking structural relaxation in polymer glasses as a sequence of elementary transitions between basins on their energy hypersurface, with transition rate constants computed from atomistic infrequent-event analysis; (c) quantifying the conditions for local interfacial failure in epoxy/graphene interfaces through stress-controlled nonequilibrium molecular dynamics simulations.