Constitutive Curve and Velocity Profile in Entangled Polymers during Start-Up of Steady Shear Flow

Handle URI:
http://hdl.handle.net/10754/597839
Title:
Constitutive Curve and Velocity Profile in Entangled Polymers during Start-Up of Steady Shear Flow
Authors:
Hayes, Keesha A.; Buckley, Mark R.; Qi, Haibo; Cohen, Itai; Archer, Lynden A.
Abstract:
Time-dependent shear stress versus shear rate, constitutive curve, and velocity profile measurements are reported in entangled polymer solutions during start-up of steady shear flow. By combining confocal microscopy and particle image velocimetry (PIV), we determine the time-dependent velocity profile in polybutadiene and polystyrene solutions seeded with fluorescent 150 nm silica and 7.5 μm melamine particles. By comparing these profiles with time-dependent constitutive curves obtained from experiment and theory, we explore the connection between transient nonmonotonic regions in the constitutive curve for an entangled polymer and its susceptibility to unstable flow by shear banding [Adams et al. Phys. Rev. Lett. 2009, 102, 067801-4]. Surprisingly, we find that even polymer systems which exhibit transient, nonmonotonic shear stress-shear rate relationships in bulk rheology experiments manifest time-dependent velocity profiles that are decidedly linear and show no evidence of unstable flow. We also report that interfacial slip plays an important role in the steady shear flow behavior of entangled polymers at shear rates above the reciprocal terminal relaxation time but has little, if any, effect on the shape of the velocity profile. © 2010 American Chemical Society.
Citation:
Hayes KA, Buckley MR, Qi H, Cohen I, Archer LA (2010) Constitutive Curve and Velocity Profile in Entangled Polymers during Start-Up of Steady Shear Flow. Macromolecules 43: 4412–4417. Available: http://dx.doi.org/10.1021/ma100162c.
Publisher:
American Chemical Society (ACS)
Journal:
Macromolecules
KAUST Grant Number:
KUSC1-018-02
Issue Date:
11-May-2010
DOI:
10.1021/ma100162c
Type:
Article
ISSN:
0024-9297; 1520-5835
Sponsors:
This work was supported by Award No. KUSC1-018-02, made by King Abdullah University of Science and Technology (KAUST) and by the National Science Foundation (Award No. CBET-0756516). We are grateful to Erik Herz and Prof. Ulrich Wiesner for providing the surface-functionalized fluorescent nanoparticle tracers used in the study.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorHayes, Keesha A.en
dc.contributor.authorBuckley, Mark R.en
dc.contributor.authorQi, Haiboen
dc.contributor.authorCohen, Itaien
dc.contributor.authorArcher, Lynden A.en
dc.date.accessioned2016-02-25T12:57:35Zen
dc.date.available2016-02-25T12:57:35Zen
dc.date.issued2010-05-11en
dc.identifier.citationHayes KA, Buckley MR, Qi H, Cohen I, Archer LA (2010) Constitutive Curve and Velocity Profile in Entangled Polymers during Start-Up of Steady Shear Flow. Macromolecules 43: 4412–4417. Available: http://dx.doi.org/10.1021/ma100162c.en
dc.identifier.issn0024-9297en
dc.identifier.issn1520-5835en
dc.identifier.doi10.1021/ma100162cen
dc.identifier.urihttp://hdl.handle.net/10754/597839en
dc.description.abstractTime-dependent shear stress versus shear rate, constitutive curve, and velocity profile measurements are reported in entangled polymer solutions during start-up of steady shear flow. By combining confocal microscopy and particle image velocimetry (PIV), we determine the time-dependent velocity profile in polybutadiene and polystyrene solutions seeded with fluorescent 150 nm silica and 7.5 μm melamine particles. By comparing these profiles with time-dependent constitutive curves obtained from experiment and theory, we explore the connection between transient nonmonotonic regions in the constitutive curve for an entangled polymer and its susceptibility to unstable flow by shear banding [Adams et al. Phys. Rev. Lett. 2009, 102, 067801-4]. Surprisingly, we find that even polymer systems which exhibit transient, nonmonotonic shear stress-shear rate relationships in bulk rheology experiments manifest time-dependent velocity profiles that are decidedly linear and show no evidence of unstable flow. We also report that interfacial slip plays an important role in the steady shear flow behavior of entangled polymers at shear rates above the reciprocal terminal relaxation time but has little, if any, effect on the shape of the velocity profile. © 2010 American Chemical Society.en
dc.description.sponsorshipThis work was supported by Award No. KUSC1-018-02, made by King Abdullah University of Science and Technology (KAUST) and by the National Science Foundation (Award No. CBET-0756516). We are grateful to Erik Herz and Prof. Ulrich Wiesner for providing the surface-functionalized fluorescent nanoparticle tracers used in the study.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleConstitutive Curve and Velocity Profile in Entangled Polymers during Start-Up of Steady Shear Flowen
dc.typeArticleen
dc.identifier.journalMacromoleculesen
dc.contributor.institutionCornell University, Ithaca, United Statesen
kaust.grant.numberKUSC1-018-02en
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