Chain tension reduces monomer friction in simulated polymer melts

Bobbili, Sai Vineeth; Milner, Scott T.

doi:10.1122/8.0000091

Cited by 15 publications

(21 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Very recently, Bobbili and Milner showed, based on beadspring simulations, that friction reduction occurs under large flow. 29 However, in this approach, the role played by the molecular environment on the friction reduction is not clear, contrary to the conclusion of Ianniruberto et al 17,18 Furthermore, it should be mentioned that in this work, friction reduction is determined by looking at the chain diffusion in the flow-direction, which does not mean that the diffusion of the chain along its contour (i.e., in the three directions) is faster under large flow. This last condition would be required in order to consider friction reduction in specific models, as for example the ones recently introduced based on a Pincus blob picture.…”

Section: Introductionmentioning

confidence: 68%

“…Very recently, Bobbili and Milner showed, based on bead-spring simulations, that friction reduction occurs under large flow . However, in this approach, the role played by the molecular environment on the friction reduction is not clear, contrary to the conclusion of Ianniruberto et al , Furthermore, it should be mentioned that in this work, friction reduction is determined by looking at the chain diffusion in the flow-direction, which does not mean that the diffusion of the chain along its contour ( i.e.…”

Section: Introductionmentioning

confidence: 75%

See 1 more Smart Citation

Investigating the Transition between Polymer Melts and Solutions in Nonlinear Elongational Flow

et al. 2021

View full text Add to dashboard Cite

The Doi-Edwards tube model, coupled with relaxation mechanisms such as reptation, contour length fluctuation and constraint release, allows to quantitatively predict the linear viscoelastic properties of entangled polymers. However, for non-linear elongational flows, large discrepancies between theoretical predictions based on the tube model and experimental results still persist today. This is in particular obvious for the experimentally observed strong qualitative differences in extensional flow of entangled polystyrene (PS) melts and solutions, despite having the same number of entanglements and exhibiting the same linear viscoelastic behaviour. The cause of this non-universality is often attributed either to a monomeric friction reduction, or to an interchain pressure effect.In this work, we investigate the changes in extensional flow behavior going from polymer solutions to the melt state. For this purpose, we measure with a filament stretching rheometer the non-linear extensional responses of differently long PS chains, both in the melt state and diluted in short chain matrices of the same polymer at varying concentrations. These concentrations have been chosen sufficiently high, such that the chains stay entangled. This allows us to discuss the influence of concentration and molar mass on the steady state elongational viscosity to highlight scaling relations.The purpose of the present work is to conduct well-defined experiments to further investigate how the steady extensional viscosity of polymer solutions and blends varies with the concentration and with the molecular weight of the chains

show abstract

Section: Introductionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 75%

Investigating the Transition between Polymer Melts and Solutions in Nonlinear Elongational Flow

et al. 2021

View full text Add to dashboard Cite

show abstract

“…% solutions). The lower value of λ E for entangled solutions is attributed to the influence of disentanglement and high stretch of the chains, contributed by non-Hookean elasticity, finite extensibility, and conformation-dependent drag. ,− In contrast, dilute polymer solutions display λ E > λ s attributed to the dramatic change in conformation, particularly for highly flexible, highly extensible polymers like PEO that can undergo coil stretch transition in response to extensional flow, leads to a longer extensional relaxation time, as detailed elsewhere. − ,− ,, …”

Section: Results and Discussionmentioning

confidence: 94%

Evaporation and Rheology Chart the Processability Map for Centrifugal Force Spinning

et al. 2021

View full text Add to dashboard Cite

We show that poly(ethylene oxide) (PEO) solutions formulated using solvent mixtures of acetonitrile (AcN) and water can be centrifugally spun into fibers. We find that spinnability and fiber morphology depend on solvent choice if polymer concentration, solution shear rheology, the number of entanglements, extensional relaxation time, and the parameters for centrifugal spinning are nearly matched. We obtain an intrinsic spinnability map for volatile entangled (VE) polymer solutions by contrasting the measured shear relaxation time with the evaporation rate determined using thermogravimetric analysis (TGA). Finally, we chart a processability map for centrifugal spinning by plotting extensional relaxation time, measured for the volatile polymer solutions using a closed-cell dripping-onto-substrate (DoS) rheometry, against the time of flight (from the nozzle to the collector) by scaling both the timescales with an evaporation time. The processability map incorporates the influence of centrifugal spinning speed, nozzle diameter, distance from the collector, ambient conditions, and solvent and polymer properties, establishing an imitable paradigm for distinguishing between spinnable and sprayable formulations.

show abstract

“…Experiments and simulations have shown that extended chains have decreased effective monomeric friction coefficients relative to their bulk, Gaussian counterparts, though the decrease depends on the chain architecture and the tension. Bobbili and Milner noted that even small values of tension ( f ∼ k B T / b ), which are approximately equivalent to the amount of tension in these graft chains, lead to an ∼2× drop in the friction coefficient. Since we see an ∼5× drop in the most extreme case, this chain extension argument only provides a partial explanation.…”

Section: Resultsmentioning

confidence: 99%

Activated Transport in Polymer Grafted Nanoparticle Melts

et al. 2021

View full text Add to dashboard Cite

We measure the activation energy for the local segmental dynamics of polymer chains densely grafted to nanoparticles (NPs) using quasielastic neutron scattering. We aim to understand the underpinning physics of the experimentally measured enhanced gas transport in polymer grafted nanoparticle-based membranes relative to the neat polymer (without NPs), especially the permeability maximum, which occurs at intermediate chain lengths. We find that the activation energy goes through a minimum as a function of chain length, while the elementary jump size goes through a maximum around the same chain length. These results, likely, are the dynamic consequence of a structural transition of the grafted polymer brush from “extended” to “interpenetrated” with increasing chain length at fixed grafting density. Evidently, the regimes of different graft chain lengths near this structural transition are associated with lower activation energy, likely due to fluctuation effects, which also lead to enhanced gas transport.

show abstract

Chain tension reduces monomer friction in simulated polymer melts

Cited by 15 publications

References 18 publications

Investigating the Transition between Polymer Melts and Solutions in Nonlinear Elongational Flow

Investigating the Transition between Polymer Melts and Solutions in Nonlinear Elongational Flow

Evaporation and Rheology Chart the Processability Map for Centrifugal Force Spinning

Activated Transport in Polymer Grafted Nanoparticle Melts

Contact Info

Product

Resources

About