Effects of excluded volume and hydrodynamic interaction on the deformation, orientation and motion of ring polymers in shear flow

Chen, Wenduo; Zhao, Hongchao; Liu, Lijun; Chen, Jizhong; Li, Yunqi; An, Lijia

doi:10.1039/c5sm00837a

Cited by 22 publications

(25 citation statements)

References 57 publications

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“…For star and ring polymers and linear chains in melt c m seems to be roughly independent of the molecular weight N. However, this seems not to be the case of linear chains in solution, as deduced from the data obtained in previous work. 17 The present findings shed light on recent literature discussions 3,13,15,19 about the different polymer architectures concerning tumbling dynamics. The conclusion is that such structure-dynamic relation is controlled by the aspect ratio G 2 /G 1 .…”

Section: Tumbling Frequency In Ring and Linear Polymerssupporting

confidence: 71%

“…Here, we focus on the origin of the breathing frequency O, so it has to be stressed that, so far, the tank-treading frequency of star molecules o R remains to be theoretically or experimentally studied. Such study should probably reveal strong similarities between tank-treading in star-molecules, in ring polymers 15,19 and also in vesicles, 21,23 even at large shear rates (see the comparison made in ref. 12).…”

Section: Tank-treading Rotationmentioning

confidence: 83%

“…15,16 This behavior is quite general and it has also been studied in linear chains (either free 17,18 or tethered 16 ) and in polymer rings under shear. 15,19 But how these signals are interpreted as motion depends on the molecule's architecture. Clearly, in shear flow, a rigid ellipsoid tumbles (turns around) with a precise frequency.…”

Section: Introductionmentioning

confidence: 99%

“…We believe these questions should be revised. Chen et al 15,19 also used MCD simulations in an attempt to discern tank-treading in ring polymers. They conclude that ring chains mostly tumble at large shear rates but have a significant probability to tank-tread (P tt C 0.2) with a frequency o R B _ g 0.…”

Section: Introductionmentioning

confidence: 99%

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Deciphering the dynamics of star molecules in shear flow

2017

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This work analyses the rotation of star polymers under shear flow, in melts, and in good solvent dilute solution. The latter is modeled by single molecule Brownian hydrodynamics, while melts are modeled using non-equilibrium molecular dynamics in closed (periodic) boxes and in open boundaries. A Dissipative Particle Dynamics (DPD) thermostat introduces pairwise monomer friction in melts at will, in directions normal and tangent to the monomer-monomer vectors. Although tangential friction is seldom modeled, we show that it is essential to control hydrodynamic effects in melts. We analyze the different sources of molecular angular momentum in solution and melts and distinguish three dynamic regimes as the shear rate [small gamma, Greek, dot above] is increased. These dynamic regimes are related with the disruption of the different relaxation mechanisms of the star in equilibrium. Although strong differences are found between harmonic springs and finitely extensible bonds, above a critical shear rate the star molecule has a "breathing" mode with successive elongations and contractions in the flow direction with frequency Ω. The force balance in the flow direction unveils a relation between Ω and the orientation angle. Using literature results for the tumbling of rings and linear chains, either in melt or in solution, we show that the relation is general. A different "tank-treading" dynamics determines the rotation of monomers around the center of mass of the molecule. We show that the tank-treading frequency does not saturate but keeps increasing with [small gamma, Greek, dot above]. This is at odds with previous studies which erroneously calculated the molecular angular frequency, used as a proxy for tank-treading.

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Section: Tumbling Frequency In Ring and Linear Polymerssupporting

confidence: 71%

Section: Tank-treading Rotationmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Deciphering the dynamics of star molecules in shear flow

2017

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“…The simulation details are as follows: The linear or ring polymer is modeled as a generic semiflexible bead-spring chain with N beads of mass M (

). The excluded-volume interactions between particles are considered by a truncated and shifted Lennard–Jones potential

[ 38 , 39 ]:

where r denotes the spatial distance between particles i and j . The parameters

and

are taken as the units of energy and length (

and

), respectively.…”

Section: Model and Simulation Methodsmentioning

confidence: 99%

Compression and Stretching of Confined Linear and Ring Polymers by Applying Force

et al. 2021

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We use Langevin dynamics to study the deformations of linear and ring polymers in different confinements by applying compression and stretching forces on their two sides. Our results show that the compression deformations are the results of an interplay among of polymer rigidity, degree of confinement, and force applied. When the applied force is beyond the threshold required for the buckling transition, the semiflexible chain under the strong confinement firstly buckles; then comes helical deformation. However, under the same force loading, the semiflexible chain under the weaker confinement exhibits buckling instability and shrinks from the folded ends/sides until it becomes three-folded structures. This happens because the strong confinement not only strongly reduces the buckling wavelength, but also increases the critical buckling force threshold. For the weakly confined polymers, in compression process, the flexible linear polymer collapses into condensed states under a small external force, whereas the ring polymer only shows slight shrinkage, due to the excluded volume interactions of two strands in the crowded states. These results are essential for understanding the deformations of the ring biomacromolecules and polymer chains in mechanical compression or driven transport.

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Application of Monte Carlo simulation in addressing key issues of complex coacervation formed by polyelectrolytes and oppositely charged colloids

Xiao

2017

Advances in Colloid and Interface Science

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Effects of excluded volume and hydrodynamic interaction on the deformation, orientation and motion of ring polymers in shear flow

Cited by 22 publications

References 57 publications

Deciphering the dynamics of star molecules in shear flow

Deciphering the dynamics of star molecules in shear flow

Compression and Stretching of Confined Linear and Ring Polymers by Applying Force

Application of Monte Carlo simulation in addressing key issues of complex coacervation formed by polyelectrolytes and oppositely charged colloids

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