Nonlinear rheology of telechelic polymer networks

Berret, Jean‐François; Séréro, Y.; Winkelman, B.; Calvet, Damien; Collet, A.; Viguier, Michel

doi:10.1122/1.1339245

Cited by 91 publications

(127 citation statements)

References 29 publications

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“…13,20) Under fast shear flow, the HEUR aq solutions exhibit significant nonlinear behavior, thickening and thinning of the steady state viscosity h , 3,5,9,11,[14][15][16][17][18][19]20,22,23) which again reflects the transient nature of the HEUR network.…”

Section: Rheology Of Aqueous Solution Of Hydrophobically Modified Ethmentioning

confidence: 96%

“…[1][2][3][4][5][6] HEUR is composed of poly(ethylene oxide) (PEO) main chain and short hydrophobic end groups such as alkyl groups, the latter associating with each other in aqueous solutions to bind the PEO chains into flower micelles. 5,6) At high concentrations c, some micelles are connected into strings (through HEUR chains having the end groups in different cores) and these strings, often referred to as super-bridges, 5,6) are organized into a transient network spreading throughout the whole solution.…”

Section: Hydrophobically-modified Ethoxylated Urethane (Heur) Ismentioning

confidence: 99%

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Rheology of Aqueous Solution of Hydrophobically Modified Ethoxylated Urethane (HEUR) with Fluorescent Probes at Chain Ends: Thinning Mechanism

Suzuki

Uneyama

Inoue

et al. 2012

J. Soc. Rheol., Jpn

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Nonlinear flow behavior and the corresponding fluorescent behavior were examined for a 3.0 wt% aqueous solution of hydrophobically modified ethoxylated urethane (HEUR; M w = 1.1×10 5 ) having fluorescent pyrenyl (Py) groups at the chain ends. These end groups associated with each other to serve as cores of HEUR flower micelles, and these micelles were further connected into super-bridges to form a transient network. Correspondingly, single-Maxwellian relaxation reflecting the thermal reorganization of this network was observed in the linear viscoelastic regime. Under steady shear flow, the HEUR solution exhibited thinning of both viscosity h (g 4 ) and first normal stress coefficient Y 1 (g 4 ) at shear rates g 4 above the equilibrium relaxation frequency 1/t . Fluorescent emission intensity I E (g 4 ) from excimers formed by Py groups associated in a hydrophobic environment of the micellar cores and the intensity I M (g 4 ) from dissociated Py groups (referred to as monomers) isolated in the aqueous phase were measured under flow simultaneously with h and Y 1 . The I E /I M ratio was found to decrease only slightly (by a factor of ~4 %) on an increase of g 4 up to 6/t well in the thinning regime. (For g 4 = 6/t , h and Y 1 decreased from respective zero-shear values by factors of ~50 % and ~75 %, respectively) Thus, the significant thinning at those g 4 was accompanied by a negligible change in the HEUR core structure that corresponds to just a slight shift of the association/dissociation balance of the Py groups to the dissociated state. From this result, the thinning is quite possibly attributed to flow-induced disruption of the network connectivity through conversion of the super-bridges into super-loops, both having the same core structure.

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Section: Rheology Of Aqueous Solution Of Hydrophobically Modified Ethmentioning

confidence: 96%

Section: Hydrophobically-modified Ethoxylated Urethane (Heur) Ismentioning

confidence: 99%

Rheology of Aqueous Solution of Hydrophobically Modified Ethoxylated Urethane (HEUR) with Fluorescent Probes at Chain Ends: Thinning Mechanism

Suzuki

Uneyama

Inoue

et al. 2012

J. Soc. Rheol., Jpn

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“…Berret et al 7,9 in the shear-thinning regime of aqueous telechelic polymer solutions and by Skrzeszewska et al 26 for telechelic polypeptides; in these studies, the stress maxima were demonstrated by particle image velocimetry, a flow visualization technique, to be due to the formation of a fracture zone within the sample. 9,26 In our solutions, deformation energies of 3-4…”

Section: Rate-dependent Mechanical Instabilitymentioning

confidence: 98%

Rate-Dependent Stiffening and Strain Localization in Physically Associating Solutions

Erk

Shull

2011

Macromolecules

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Model physically associating solutions of acrylic triblock copolymer molecules in a midblockselective solvent displayed nonlinear strain-stiffening behavior which transitioned to rapid strain softening during shear start-up experiments at reduced rates spanning almost 4 orders of magnitude. Softening was believed to result from the shear-induced formation of highly localized regions of deformation in the macromolecular network. This behavior was accurately captured by a model that incorporated the strain energy and relaxation behavior of individual network strands in the solution. Flow curves predicted from the model were nonmonotonic, consistent with the onset of flow instabilities at high shear rates. The nonlinear stress response reported here, coupled with the wide range of accessible relaxation times of these thermoreversible solutions, makes them ideal model systems for studies of failure-mode transitions in physically associating solutions and gels.

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“…Strain hardening in shear has been already observed for aqueous solutions of associative polymers and attributed to chain stretching of segments trapped by supramolecular bonds. [48][49][50] (a) In analogy to the extensional behavior, strain hardening in shear is attributed to stretching of the dendrons before bond-breakage occurs. In particular, the transition from ductile to brittle behavior in extension can be related to the capacity of UPy-DPs to undergo shear thinning in simple shear.…”

Section: Iii41 Uniaxial Extension Pg1-40-mentioning

confidence: 99%

Dendronized Polymers with Ureidopyrimidinone Groups: An Efficient Strategy To Tailor Intermolecular Interactions, Rheology, and Fracture

et al. 2017

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Nonlinear rheology of telechelic polymer networks

Cited by 91 publications

References 29 publications

Rheology of Aqueous Solution of Hydrophobically Modified Ethoxylated Urethane (HEUR) with Fluorescent Probes at Chain Ends: Thinning Mechanism

Rheology of Aqueous Solution of Hydrophobically Modified Ethoxylated Urethane (HEUR) with Fluorescent Probes at Chain Ends: Thinning Mechanism

Rate-Dependent Stiffening and Strain Localization in Physically Associating Solutions

Dendronized Polymers with Ureidopyrimidinone Groups: An Efficient Strategy To Tailor Intermolecular Interactions, Rheology, and Fracture

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