Discussion of paper by J. Brassinne, A. Cadix, J. Wilson and E. van Ruymbeke, entitled ‘Dissociating sticker dynamics from chain relaxation in supramolecular polymer networks – The importance of free partner!’

TLDR: In this paper, the importance of free associating sites in the macroscopic relaxation of supramolecular networks constructed from ultrahigh molecular weight polymers with sparsely distributed stickers of finite functionality was observed.

Abstract: Associating polymers constitute a fascinating class of materials because of the richness in their rheological behavior. Their rheology is known to be mainly dictated by the nature and intrinsic stabilities of transient associations. Here, we provide a direct observation of the importance of free associating sites in the macroscopic relaxation of supramolecular networks constructed from ultrahigh molecular weight polymers with sparsely distributed stickers of finite functionality. Their rheological signature affords evidence that the macroscopic relaxation of supramolecular networks can be apparently dissociated from the intrinsic lifetime of the associating units, provided that diffusion processes do not lead to successful chain relaxation at the microscopic level.