Topology-dependent polymer stretching and scission in solution at extreme shear rates

Published

October 23, 2025

Author(s)

Bas van Ravensteijn, Patrick Corona, Anukta Data, Kexin Dai, Raghida Bou Zerdan, Kathleen Weigandt, Ryan Murphy, Craig Hawker, Matthew Helgeson

Abstract

There has been significant recent interest in engineering polymer topology to control rheology and mechanical stability in dilute solutions for applications involving extreme shear rate flows. However, methods to experimentally probe properties at relevant shear rates (≈ 104 − 106s-1) have remained ex situ, obscuring access to measures of polymer deformation and rheology that would otherwise provide mechanistic insight into the topology-dependent properties that control their behavior in extreme shear flows. In this study, we used novel in situ small angle neutron scattering measurements in a capillary rheometer (capillary rheo-SANS) to simultaneously measure solution viscosities and polymer deformations in high shear on a series of chemically homologous topology-defined polymers including linear, randomly branched, and star-shaped molecules. We demonstrate that differences in the onset of chain stretching and shear thinning of these polymers in dilute solution are controlled primarily by differences in their molecular relaxation time, which dominate strain-rate dependent stretching in shearing flows. These differences correlate with differences in chain scission inferred from ex situ measurements at more extreme shear rates. Together, the results demonstrate a direct coupling between chain deformation and scission, and suggest that the dominant effect of branching as a means to impart resilience against mechanical degradation is through differences in relaxation dynamics due to branching. We anticipate that these results will provide key insights to engineer topology-controlled polymers for rheological modification, mechanical stability, and controlled mechano-chemistry.

Citation

ACS Polymers Au

Pub Type

Journals

Keywords

CR-SANS, RheoSANS, Polymers, Scission, Complex Fluids, SANS

Citation

van Ravensteijn, B. , Corona, P. , Data, A. , Dai, K. , Bou Zerdan, R. , Weigandt, K. , Murphy, R. , Hawker, C. and Helgeson, M. (2025), Topology-dependent polymer stretching and scission in solution at extreme shear rates, ACS Polymers Au (Accessed January 8, 2026)