Mechanism of Shear Thickening in Reversibly Cross-linked Supramolecular Polymer Networks.
Abstract
We report here the nonlinear rheological properties of metallo-supramolecular networks
formed by the reversible cross-linking of semi-dilute unentangled solutions of poly(4-vinylpyridine)
(PVP) in dimethyl sulfoxide (DMSO). The reversible cross-linkers are bis-Pd(II) or
bis-Pt(II) complexes that coordinate to the pyridine functional groups on the PVP.
Under steady shear, shear thickening is observed above a critical shear rate, and
that critical shear rate is experimentally correlated with the lifetime of the metal-ligand
bond. The onset and magnitude of the shear thickening depend on the amount of cross-linkers
added. In contrast to the behavior observed in most transient networks, the time scale
of network relaxation is found to increase during shear thickening. The primary mechanism
of shear thickening is ascribed to the shear-induced transformation of intrachain
cross-linking to interchain cross-linking, rather than nonlinear high tension along
polymer chains that are stretched beyond the Gaussian range.
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https://hdl.handle.net/10161/4090Published Version (Please cite this version)
10.1021/ma100093bPublication Info
Xu, Donghua; Hawk, Jennifer L; Loveless, David M; Jeon, Sung Lan; & Craig, Stephen
L (2010). Mechanism of Shear Thickening in Reversibly Cross-linked Supramolecular Polymer Networks.
Macromolecules, 43(7). pp. 3556-3565. 10.1021/ma100093b. Retrieved from https://hdl.handle.net/10161/4090.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Stephen L Craig
William T. Miller Distinguished Professor of Chemistry
Research interests in Prof. Craig's group bridge physical organic and materials chemistry.
Many of these interests are guided by the vision that important challenges in materials
science might be better tackled not from the traditional perspective of an engineer,
but rather from the molecular perspective of an organic chemist. Current interests
include the design and synthesis of self-healing polymers and the use of modern mechanochemistry
in new stress-responsive polymers, catalysis, and the st

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