Dominance of Chain Entanglement over Transient Sticking on Chain Dynamics in Hydrogen-Bonded Supramolecular Polymer Networks in the Melt

The chain dynamics in supramolecular polymer networks is determined by the interplay of the kinetics of transient interchain association and relaxation of the network chains themselves. This interplay can be addressed by studying model supramolecular polymer networks in which the number of associative side groups and the molar mass of the covalently jointed backbone polymers are both varied systematically. To realize this idea, we use precursor chains with three different molar masses, which comes along with different extents of entanglement in the melt state. For each molar mass, the precursor polymers are functionalized with three different relative contents of associative side groups, giving rise to transient network formation in the melt state. We evaluate the chain dynamics in these transient networks by probing the diffusivity of fluorescently labeled tracer chains by fluorescence recovery after photobleaching (FRAP). In these studies, we find that the presence of entanglements markedly outweighs the influence of transient associative interactions.