Computer simulations of amorphous polymers: From quantum mechanical calculations to mesoscopic models

The development of computational methods for predicting the structure and properties of complex macromolecular systems in condensed phases, e.g. amorphous and melted states, has provided the basis of the hierarchical modeling strategies currently used in polymer science. This paper reviews some methods, many of them developed or extensively applied by the researchers in the groups of Madrid and Barcelona, that appear particularly promising. Specifically, after a brief discussion about the applicability of quantum mechanical methods to the development of reliable force-field parameters for condensed-phase studies, this work describes: (a) strategies recently reported for atomistic simulations of hetereogeneously ordered multichain denses systems, i.e. a procedure based on a random search of microstructures with minimum energy and advanced Monte Carlo methods; and (b) methodologies to study the mesoscopic properties or amorphous and melted polymer, i.e. pseudoparticle-based algorithms and the primitive path network. The examples chosen to illustrate the performance of the different methods have been focused on polyethylene to illustrate the different stages within the hierarchical approach.