Flow-induced nucleation in polymer melts: a study of the GO model for pure and bimodal blends, under shear and extensional flow

Jolley, Kenny; Graham, Richard S.

doi:10.1007/s00397-012-0663-5

Cited by 10 publications

(25 citation statements)

References 19 publications

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“…This approach has been used, with modification in some cases, in a number of other studies [60][61][62][63]. In a kinetic Monte Carlo study, Jolley and Graham [64] included a contribution from the change in elastic free energy arising from the reduction in entropy for a chain segment stretched in flow, from which they obtained semi-analytic results for the enhancement factor, IS/IS,q.…”

Section: Assessment Of Free Energy Fen Modelsmentioning

confidence: 99%

An assessment of models for flow-enhanced nucleation in an n-alkane melt by molecular simulation

Nicholson

2019

Journal of Rheology

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Flow-enhanced nucleation of the crystal phase under shear and uniaxial extension for a monodisperse melt of n-pentacontahectane (C150H302, or C150) chains was studied by nonequilibrium molecular dynamics (NEMD) simulation. The resulting acceleration in the crystal nucleation rate was correlated with macroscopically measurable properties of the flow field and with microscopic conformational statistics. Based on the fidelity of the observed correlations, several empirical models reported in the literature were evaluated for their abilities to account for the observed enhancement of the nucleation rate due to flow, and new models are proposed for data that do not comport with existing models. In agreement with prior reports, the nucleation rate was found to correlate well with first normal stress difference, the second invariant of the deviatoric conformation tensor, and the stretch ratio, albeit with some differences from the existing models. New models based on conformational invariants for Kuhn segments are proposed, and shown to describe the simulation data more accurately than those based on conformational behavior of entire chains. Within the applicability of the stress-optical rule, related models are proposed based on invariants of the extra stress tensor.

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Section: Assessment Of Free Energy Fen Modelsmentioning

confidence: 99%

An assessment of models for flow-enhanced nucleation in an n-alkane melt by molecular simulation

Nicholson

2019

Journal of Rheology

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“…This approach was used to capture quiescent crystal growth [82,83] A fast nucleation algorithm [85] has allowed the simulation of high nucleation barriers, which has enabled successful comparison with FIC experiments [86]. All kMC algorithms require a priori choices for which moves are simulated and their rates.…”

Section: Kinetic Monte Carlo Simulationsmentioning

confidence: 99%

“…Continuing, the same authors developed a method to project the GO model onto a onedimensional nucleation model [88] (see figure 1(c)). Jolley and Graham [86] then solved this model analytically, via some empirically validated approximations. The result is a version of classical nucleation theory that captures the GO model's simulation results.…”

Section: Kinetic Monte Carlo Simulationsmentioning

confidence: 99%

“…This section will focus on predicting the nucleation rate under flow as a prerequisite to explaining and predicting more drastic FIC effects such as shish-kebab formation. I will use the GO model as an illustrative example because some integration tools are already in place [85,88] and some analytic solutions are known for this model [86,87]. Similar approaches may also enable other coarse-grained simulation methods, such as [80,81], to bridge from MD to continuum models.…”

Section: Linking To Other Levels Of Modellingmentioning

confidence: 99%

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Understanding flow-induced crystallization in polymers: A perspective on the role of molecular simulations

Graham

2019

Journal of Rheology

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Flow induced crystallisation in polymers is an important problem in both fundamental polymer science and industrial polymer processing. The key process of flow-induced nucleation occurs on a very rapid timescale and on a highly localised lengthscale and so is extremely difficult to observe directly in experiments. However, recent advances in molecular dynamics simulations mean that flowinduced nucleation can be simulated at an achievable computational cost. Such studies offer unrivalled time and lengthscale resolution of the nucleation process. Nevertheless, the computational cost of molecular dynamics places considerable constraints on the range of molecular weights, temperature and polydispersity that can be studied. In this review I will discuss recent progress, describe how future work might resolve or work around the constraints of molecular simulation and examine how multiscale modelling could translate molecular insight into improved polymer processing.

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“…The materials classes and topics also range broadly, from fundamentals in suspension mechanics (Khair and Star 2012;D'Avino 2013;van Deen et al 2013), over more complex materials such as mixtures of foams and pastes (Kogan et al 2013), to really complex materials such as cement formulations (Pasquino et al 2013). In the area of polymeric systems, the applications discussed range from nonlinear viscoelasticity (Ewoldt and Bharadwaj 2013) over studies of flow-enhanced nucleation in polymers (Jolley and Graham 2012) and stimuli responsive hydrogels, either in extensional flow (Stadler et al 2013) or at interfaces (Cohin et al 2013).…”

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confidence: 99%

Special issue devoted to novel trends in rheology

Vermant

Winter²

2013

Rheol Acta

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Flow-induced nucleation in polymer melts: a study of the GO model for pure and bimodal blends, under shear and extensional flow

Cited by 10 publications

References 19 publications

An assessment of models for flow-enhanced nucleation in an n-alkane melt by molecular simulation

An assessment of models for flow-enhanced nucleation in an n-alkane melt by molecular simulation

Understanding flow-induced crystallization in polymers: A perspective on the role of molecular simulations

Special issue devoted to novel trends in rheology

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