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

Abstract

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.

Dynamics of supramolecular associative polymer networks at the interplay of chain entanglement, transient chain association, and chain‐sticker clustering

“…(C)]. This sample has a marked amount of ~8 mol % of free OH groups along its precursor chains that might be suspect to form hydrogen bonds with the UPy moieties and thereby suppress strong polymer interlinkage by UPy dimerization . As a consequence, such samples should have very low amounts of trapped segments, and therefore, at the low‐frequency end of their rheological spectra, a crossover of G ′ and G ″ followed by a terminal flow region should be observed .…”

“…With that, studying the dynamics and mechanical properties of side‐supra networks as a function of N e and f and investigation of the potential interdependency and interplay of these parameters is possible with great extent and versatility. Recently, we relied on that premise and studied the diffusive and relaxational chain dynamics of a library of solvent‐free side‐supra networks based on poly(butyl acrylate‐ ran ‐hydroxylethyl acrylate) and ureidopyrimidinone (UPy), associative side groups . The molar mass and the UPy content of these networks were varied systematically, and their chain dynamics was studied as a function of these parameters using fluorescence recovery after photobleaching and oscillatory shear rheology.…”

Association and relaxation of supra-macromolecular polymers

“…Polymers functionalised with reversibly associative substituents, driven by non-covalent interactions, have gained much interest in recent years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] in a variety of materials science applications. These include reversible blending of immiscible polymers, 16 self-healing, [17][18][19] improved processability 4,20,21 and smart adhesive surfaces.…”

Dynamics of Supramolecular Self-Healing Recovery in Extension

“…In unassociating linear polymers, rates of extension faster than the inverse Rouse time induce chain stretch and entanglements dominate the measurement. 34,61,62 For nBA-AA, entanglements are argued to be fully recovered at about τ H ≈ 10s. The sharp increase in R σ observed at τ H ≈ 10s suggests that the response is strongly dependent on the presence of entanglements and is relatively insensitive to recovery of associations, which gradually increase recovery.…”

“…29 It is well understood that associating chemical groups delay diffusion and reptation of chains. [34][35][36] However, there is a complex relationship between competing timescales that are not well understood. In this work, we correlate measured association dynamics with well-defined timescales to determine the mechanisms and extent of recovery expected for associating polymers with and without entanglements.…”