Multiple Dynamic Processes Contribute to the Complex Steady Shear Behavior of Cross-Linked Supramolecular Networks of Semidilute Entangled Polymer Solutions.

Journal Article

Molecular theories of shear thickening and shear thinning in associative polymer networks are typically united in that they involve a single kinetic parameter that describes the network -- a relaxation time that is related to the lifetime of the associative bonds. Here we report the steady-shear behavior of two structurally identical metallo-supramolecular polymer networks, for which single-relaxation parameter models break down in dramatic fashion. The networks are formed by the addition of reversible cross-linkers to semidilute entangled solutions of PVP in DMSO, and they differ only in the lifetime of the reversible cross-links. Shear thickening is observed for cross-linkers that have a slower dissociation rate (17 s(-1)), while shear thinning is observed for samples that have a faster dissociation rate (ca. 1400 s(-1)). The difference in the steady shear behavior of the unentangled vs. entangled regime reveals an unexpected, additional competing relaxation, ascribed to topological disentanglement in the semidilute entangled regime that contributes to the rheological properties.

Full Text

Duke Authors

Cited Authors

  • Xu, D; Craig, SL

Published Date

  • June 3, 2010

Published In

Volume / Issue

  • 1 / 11

Start / End Page

  • 1683 - 1686

PubMed ID

  • 20606721

Electronic International Standard Serial Number (EISSN)

  • 1948-7185

Digital Object Identifier (DOI)

  • 10.1021/jz1004818

Language

  • eng

Conference Location

  • United States