Macromolecular topology and rheology: beyond the tube model

Vlassopoulos, Dimitris

doi:10.1007/s00397-016-0948-1

Cited by 51 publications

(63 citation statements)

References 238 publications

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“…Considerable progress has been made in describing, from a theoretical and practical point of view, the linear and nonlinear rheology of nearly monodisperse linear polymers [1]. Building on the early work of de Gennes [4,5] and Doi and Edwards [6], modern constitutive models (such as the so-called GLaMM (Graham, Likhtman and McLeish, Milner) model [7]) have been developed to incorporate fundamental molecular stress relaxation processes such as reptation, chain retraction, and convective constraint release (CCR) [8]. These models make quantitative predictions that are generally in good agreement with experimental data for monodisperse melts in strong (nonlinear) flow conditions [9].…”

Section: A Polydispersity In Entangled Polymersmentioning

confidence: 99%

Nonlinear rheology of polydisperse blends of entangled linear polymers: Rolie-Double-Poly models

Boudara

Peterson

Leal

et al. 2018

Journal of Rheology

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While there has been much success in modeling the linear and nonlinear rheology of monodisperse entangled linear polymers, progress in the constitutive modeling of polymeric materials continues to lag behind the needs of industry. Industrially sourced polymers are typically polydisperse (comprising a broad distribution of molecular weights), making their rheology more suitable for processing but also more difficult to predict. To date, there are no molecular-based constitutive models that are practically suitable for describing industrially relevant polymers in industrially relevant flows. In this article, we extend but strongly simplify the model of Read et al. [J. Rheol. 56, 823-873 (2012)], which is able to predict the linear and nonlinear rheology of bidisperse blends but is prohibitively complex for industrial use. We propose a pair of simplified tube models for polydisperse melts of entangled linear polymers that combine the success of the double reptation approximation [des Cloizeaux, Europhys. Lett. 5, 437-442 (1988)] in the linear regime with the success of the Rolie-Poly constitutive equation [Likhtman et al., J. Non Newtonian Fluid Mech. 114, 1-12 (2003)] in the nonlinear regime. We first review the key concepts of the double reptation approximation and the original (monodisperse) Rolie-Poly constitutive model. Subsequently, we provide the details of our approximate models for the particular case of a bidisperse blend and show that these models naturally identify the effects from couplings between constraint release and chain retraction (i.e., the so-called "enhanced stretch relaxation time"). Finally, we generalize to a multicomponent (polydisperse) model, based on the same underlying principles. Along the way, we also show that both of our models are in qualitative, and largely quantitative, agreement with experimental data for bidisperse and polydisperse melts of entangled linear polymers.

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Section: A Polydispersity In Entangled Polymersmentioning

confidence: 99%

Nonlinear rheology of polydisperse blends of entangled linear polymers: Rolie-Double-Poly models

Boudara

Peterson

Leal

et al. 2018

Journal of Rheology

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“…5,6 Despite the wide use of such models in the last three decades, a universal description of the dynamics of polymers with different molecular architectures in melt conditions is lacking. 7 Recent work has established that the Rouse model is not generally applicable even in the relatively simple case of unentangled polymers 8–11 so we take a fresh look at the problem of the dynamics of unentangled polymer melts based on established hydrodynamic models and the assumption that continuum hydrodynamic theory is applicable to molecular fluids.…”

Section: Introductionmentioning

confidence: 99%

Influence of polymer architectures on diffusion in unentangled polymer melts

2017

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Recent simulations have indicated that the thermodynamic properties and the glassy dynamics of polymer melts are strongly influenced by average molecular shape, as quantified by the radius of gyration tensor of the polymer molecules, and that average molecular shape can be tuned by varying molecular topology (e.g., ring, star, linear chain, etc.). In the present work, we investigate if molecular shape is similarly a predominant factor in understanding the polymer center of mass diffusion D in the melt, as already established for polymer solutions. We find that all our D data for unentangled polymer melts having a range of topologies can be reasonably described as a power law of the polymer hydrodynamic radius Rh. In particular, this scaling is similar to the scaling of D for a tracer sphere having a radius on the order of the chain radius of gyration, Rg. We conclude that chain topology influences molecular dynamics in as much as the polymer topology influences average molecular shape. Experimental evidence seems to suggest that this situation is also true for entangled polymer melts.

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“…Introduction -The behaviour of unknotted and mutually unlinked ring polymers in dense solutions and melts is a yet unsolved issue in Polymer Physics [1], and it has stimulated much theoretical [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and experimental [19][20][21][22][23][24] work in last decades. One of the most elusive aspects of this problem is the interplay between topological constraints (TCs) and both, structure and dynamics of the rings, which looks far more intricate than in their linear analogs.…”

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confidence: 99%

Glassiness and Heterogeneous Dynamics in Dense Solutions of Ring Polymers

2017

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Understanding how topological constraints affect the dynamics of polymers in solution is at the basis of any polymer theory and it is particularly needed for melts of rings. These polymers fold as crumpled and space-filling objects and, yet, they display a large number of topological constraints. To understand their role, here we systematically probe the response of solutions of rings at various densities to "random pinning" perturbations. We show that these perturbations trigger non-Gaussian and heterogeneous dynamics, eventually leading to nonergodic and glassy behavior. We then derive universal scaling relations for the values of solution density and polymer length marking the onset of vitrification in unperturbed solutions. Finally, we directly connect the heterogeneous dynamics of the rings with their spatial organization and mutual interpenetration. Our results suggest that deviations from the typical behavior observed in systems of linear polymers may originate from architecture-specific (threading) topological constraints.

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Macromolecular topology and rheology: beyond the tube model

Cited by 51 publications

References 238 publications

Nonlinear rheology of polydisperse blends of entangled linear polymers: Rolie-Double-Poly models

Nonlinear rheology of polydisperse blends of entangled linear polymers: Rolie-Double-Poly models

Influence of polymer architectures on diffusion in unentangled polymer melts

Glassiness and Heterogeneous Dynamics in Dense Solutions of Ring Polymers

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