Chain dimensions and dynamic dilution in branched polymers

Abstract

We revisit old ideas for classifying branched polymers based on their size or intrinsic viscosity relative to that of respective linear chains and complement them with an analysis of their dynamics, which is based on the concepts of hierarchical relaxation and dynamic dilution. By using several old and new datasets from different well-defined polymer architectures such as combs, H-polymers, and stars, we quantify the role of diluted entanglements on the viscoelastic properties. We suggest that the combination of static and dynamic data on sizes and relaxation mechanisms (and in particular accounting for dynamic dilution), respectively, provides a complete quantitative characterization of branched polymers over a wide range of architectures. The combined generic phenomenological description based on specific scaling parameters (branching number, backbone fraction, diluted number of entanglements, packing length) may provide useful information about complex polymers without resorting to detailed molecular modeling and moreover, allow designing or selecting specific macromolecular systems with desired properties.