Models of shear-thickening behavior in physically crosslinked networks

Marrucci, G.; Bhargava, Swati; Cooper, Stuart L.

doi:10.1021/ma00076a027

Cited by 173 publications

(216 citation statements)

References 6 publications

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“…If interactions are favored kinetically, shear thickening can be observed (19). Shear increases the collision rate of individual proteins or assemblies (20) by increasing the root-mean-square projection of the dangling end in the deformation direction. Such behavior was observed for eADF3 colloidal assemblies, which can interact during elongational flow upon increase of the hit rate of dangling ends (19).…”

Section: Resultsmentioning

confidence: 99%

“…eADF4 spherical colloidal assemblies are apparently ''smooth,'' no dangling ends stick out and contribute to sticking interactions with neighboring colloidal assemblies. In contrast, eADF3 spherical colloidal assemblies are supposed to have dangling ends, which can mediate interactions between neighboring aggregates (19,20). Moreover, eADF3 spherical aggregates can be dissolved before aggregation into fibers.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Assembly mechanism of recombinant spider silk proteins

Rammensee¹,

Slotta

Scheibel

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

350

377

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Spider silk threads are formed by the irreversible aggregation of silk proteins in a spinning duct with dimensions of only a few micrometers. Here, we present a microfluidic device in which engineered and recombinantly produced spider dragline silk proteins eADF3 (engineered Araneus diadematus fibroin) and eADF4 are assembled into fibers. Our approach allows the direct observation and identification of the essential parameters of dragline silk assembly. Changes in ionic conditions and pH result in aggregation of the two proteins. Assembly of eADF3 fibers was induced only in the presence of an elongational flow component. Strikingly, eADF4 formed fibers only in combination with eADF3. On the basis of these results, we propose a model for dragline silk aggregation and early steps of fiber assembly in the microscopic regime.colloids ͉ microfluidics ͉ protein materials ͉ rheology

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Assembly mechanism of recombinant spider silk proteins

Rammensee¹,

Slotta

Scheibel

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

350

377

View full text Add to dashboard Cite

show abstract

“…In some of conventionally examined transient network models, the shear thickening and thinning are explained as a result of the competition between two factors; the nonlinear elasticity and the stretch dependent dissociation rate [11][12][13][14][15][16][17]. Under fast flow, the nonlinear elasticity increases the shear stress whereas the stretch dependent dissociation decreases the number of highly stretched chains and thus decreases the shear stress.…”

Section: Nonlinear Elasticity and Stretch Dependent Reconstructionmentioning

confidence: 99%

Concentration dependence of rheological properties of telechelic associative polymer solutions

2012

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We consider concentration dependence of rheological properties of associative telechelic polymer solutions. Experimental results for model telechelic polymer solutions show rather strong concentration dependence of rheological properties. For solutions with relatively high concentrations, linear viscoelasticity deviates from the single Maxwell behavior. The concentration dependence of characteristic relaxation time and moduli is different in high and low concentration cases. These results suggest that there are two different concentration regimes. We expect that densely connected (well percolated) networks are formed in high-concentration solutions, whereas sparsely connected (weakly percolated) networks are formed in low-concentration solutions. We propose single chain type transient network models to explain experimental results. Our models incorporate the spatial correlation effect of micellar cores and average number of elastically active chains per micellar core (the network functionality). Our models can reproduce non-single Maxwellian relaxation and nonlinear rheological behavior such as the shear thickening and thinning. They are qualitatively consistent with experimental results. In our models, the linear rheological behavior is mainly attributable to the difference of network structures (functionalities). The nonlinear rheological behavior is attributable to the nonlinear flow rate dependence of the spatial correlation of micellar core positions.

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“…In all transient network theories proposed so far [20,21,22,23,24,26,28,29], it is implicitly assumed that a fictitious network exists a priori (see Fig.1 (i)). This network matrix is not a substantial one in a sense that it itself does not contribute to the elasticity of the system, but it plays a role as a substrate of the chains on which association/dissociation of the end groups takes place.…”

Section: Introductionmentioning

confidence: 99%

Rheological study of transient networks with junctions of limited multiplicity

Indei

2007

The Journal of Chemical Physics

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Viscoelastic and thermodynamic properties of transient gels comprised of telechelic polymers are theoretically studied. We extend classical theories of transient networks so that correlations among polymer chains through the network junctions are taken into account. This extension enables us to investigate how rheological quantities, such as viscosity and elastic modulus, are affected by the association equilibrium conditions, and how these quantities are related to the aggregation number of junctions. We present a theoretical model of transient networks with junctions comprised of variable number of hydrophobic groups on the chain ends. Elastically effective chains are defined as the chains whose both ends are associated with end groups on other chains. It is shown that the dynamic shear moduli are well described in terms of the Maxwell model characterized by a single relaxation time and the high-frequency plateau modulus as in the classical theories, but the reduced dynamic shear moduli depend on the polymer concentration and temperature through the reduced concentration c given as a combination of the association constant and the volume fraction of end groups. The plateau modulus and the zero-shear viscosity rise nonlinearly with increasing c when c is small, but they are proportional to c for higher c. The relaxation time also increases as c increases due to the presence of pairwise junctions at small c.

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Models of shear-thickening behavior in physically crosslinked networks

Cited by 173 publications

References 6 publications

Assembly mechanism of recombinant spider silk proteins

Assembly mechanism of recombinant spider silk proteins

Concentration dependence of rheological properties of telechelic associative polymer solutions

Rheological study of transient networks with junctions of limited multiplicity

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