Understanding the molecular origin of shear thinning in associative polymers through quantification of bond dissociation under shear
Name
PhysRevMaterials.4.055602.pdf
Description
Published version
Size
1.33 MB
Format
Adobe PDF
Checksum (MD5)
2b4007db87febae1fa10fd1b0fe86a69
Author(s)
Mahmad Rasid, Irina
Ramirez, Jorge
Olsen, Bradley D
Holten-Andersen, Niels
Date Issued
2020
Journal
Physical Review Materials
Publisher
American Physical Society (APS)
Version
Final published version
Abstract
© 2020 American Physical Society. Understanding the physics of associative polymers is often limited by our inability to directly measure bond dissociation under deformation. In this work, we developed a rheo-fluorescence technique and applied it to characterize the nonlinear shear response of linear side-functionalized polymer chains cross-linked via nickel-terpyridine complexation. As the network was sheared, the fraction of dissociated bonds was quantitatively measured based upon a change in fluorescence with metal dissociation. Shear thinning of the gel was accompanied by only a small increase in the fraction of dissociated bonds. Comparison with several transient network models shows that the shear thinning within the constraint of the measured fraction of dissociated bonds cannot be explained by classical theories that include retraction of dangling chains alone; the rheological response likely involves alternative modes of stress relaxation.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
https://doi.org/10.1103/PHYSREVMATERIALS.4.055602
