Threading-Induced Dynamical Transition in Tadpole-Shaped Polymers.

Angelo Rosa,Jan Smrek,Davide Michieletto,Matthew S Turner

doi:10.1021/acsmacrolett.0c00197

Abstract

The relationship between polymer topology and bulk rheology remains a key question in soft matter physics. Architecture-specific constraints (or threadings) are thought to control the dynamics of ring polymers in ring–linear blends, which thus affects the viscosity to range between that of the pure rings and a value larger, but still comparable to, that of the pure linear melt. Here we consider qualitatively different systems of linear and ring polymers, fused together in “chimeric” architectures. The simplest example of this family is a “tadpole”-shaped polymer, a single ring fused to the end of a single linear chain. We show that polymers with this architecture display a threading-induced dynamical transition that substantially slows chain relaxation. Our findings shed light on how threadings control dynamics and may inform design principles for chimeric polymers with topologically tunable bulk rheological properties.

Highlights

The relationship between polymer topology and bulk rheology remains a key question in soft matter physics
The presence of even a small fraction of linear contaminants dramatically slows their dynamics through ring−linear interpenetration.[11,24−27] This slowing down shares some similarities with the one computationally discovered in systems of pure rings,[28−31] where interring threadings drive a “topological glass” state due to a hierarchical network of threadings: ring-specific topological constraints.[32−36] In ring−linear blends, the linear chains cannot set up a hierarchical network of constraints and the rings are bound to relax on time scales comparable to the reptative disengagement of the linear chains[4,37−39] which perform most of the threadings: this limits severely any opportunities for further tuning of bulk rheology by using pure mixtures of ring and linear chains
Inspired by quickly progressing technical advances in topological polymer synthesis,[40−42] here we investigate the behavior of polymer architectures that simultaneously display linear and unknotted and unlinked circular topologies

Summary

Corresponding Authors

Turner − Department of Physics and Centre for Complexity Science, University of Warwick, Coventry CV4 7AL, United Kingdom; Department of Chemical Engineering, Kyoto University, Kyoto 606-8501, Japan; Email: M.S.Turner@ warwick.ac.uk.

■ ACKNOWLEDGMENTS

■ REFERENCES