ABSTRACT
Crystallizable polymers constitute the majority of plastics in current use. Nevertheless, the study of polymer crystals by molecular simulations requires concepts and techniques somewhat different from those invoked by conventional views of polymer melts and glasses. Amorphous polymers are liquid-like in their structure; they exhibit only short range order. Amorphous melts are liquid-like in their dynamics as well. The methods employed to study amorphous polymers thus rely heavily on the Monte Carlo and molecular dynamics methods developed in the 1950s and 1960s to study simple liquids, and on refinements which permit efficient sampling of the vast conformation space available to a polymer “coil” in the amorphous state. Polymer crystals, on the other hand, exhibit long range order similar to that found in small molecule solids; they are characterized by high density, limited conformation space, and pronounced anisotropy. The study of crystalline polymers benefits considerably from the solid-state physics developed in the first half of the twentieth century. However, polymer crystals differ in several important respects from simple atomic crystals, and the modern simulation of polymer crystals draws upon ideas from both solid-state and fluid-state physics.
