Unexpected Stretching of Entangled Ring Macromolecules

Huang, Qian; Ahn, Jungkyu; Parisi, Daniele; Chang, Taihyun; Hassager, Ole; Panyukov, Sergey; Rubinstein, Michael; Vlassopoulos, Dimitris

doi:10.1103/physrevlett.122.208001

Cited by 91 publications

(98 citation statements)

References 41 publications

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“…This view of silk registration is highly idealised, in particular because associating polymers exhibit a broad stretch distribution in steady-state flow. Indeed, akin to ring polymers [ 55 , 56 ], rare events of large chain stretches emerge below the stretch transition. We speculate that the width of the distribution determines how likely it is for equally stretched polymers to associate with each other, such that a correlated ‘registered’ network may form.…”

Section: Discussionmentioning

confidence: 99%

Stretching of Bombyx mori Silk Protein in Flow

et al. 2021

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The flow-induced self-assembly of entangled Bombyx mori silk proteins is hypothesised to be aided by the ‘registration’ of aligned protein chains using intermolecularly interacting ‘sticky’ patches. This suggests that upon chain alignment, a hierarchical network forms that collectively stretches and induces nucleation in a precisely controlled way. Through the lens of polymer physics, we argue that if all chains would stretch to a similar extent, a clear correlation length of the stickers in the direction of the flow emerges, which may indeed favour such a registration effect. Through simulations in both extensional flow and shear, we show that there is, on the other hand, a very broad distribution of protein–chain stretch, which suggests the registration of proteins is not directly coupled to the applied strain, but may be a slow statistical process. This qualitative prediction seems to be consistent with the large strains (i.e., at long time scales) required to induce gelation in our rheological measurements under constant shear. We discuss our perspective of how the flow-induced self-assembly of silk may be addressed by new experiments and model development.

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Section: Discussionmentioning

confidence: 99%

Stretching of Bombyx mori Silk Protein in Flow

et al. 2021

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“…Although the combination of various polymer architectures (linear, star, dendritic) and amphiphilicity has attracted a great deal of attention, amphiphilic ring polymers have hardly been studied up to date. This is an important missing piece of the picture, as ring polymers are known to be significantly different from linear ones in a number of ways, including their overall statistical-mechanical properties [36,42], their rheology [32], and their ability to form specific types of threading that result into glassy states in the melt [30,37,38,54]. Cyclic block copolymers that feature chemically distinct sequences are thus forming excellent experimental systems to study the self-assembly of block copolymer rings in finite concentration [31,55,65].…”

Section: Introductionmentioning

confidence: 99%

Aggregation shapes of amphiphilic ring polymers: from spherical to toroidal micelles

Jehser

Likos

2020

Colloid Polym Sci

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The self-assembly of Janus ring polymers is studied via a coarse-grained molecular dynamics employing a bead spring model including bending rigidity contributions to the Hamiltonian. We examine the formation and the morphology of amphiphilicitydriven clusters in the system using the number density ρ N , the temperature T, the fraction of solvophobic monomers α, and the stiffness of the polymer rings κ as control parameters. We present a quantitative analysis of several characteristics for the formed clusters of Janus rings. Measured quantities include the distribution of the cluster size M C and the shape of the clusters in the form of the prolate/oblate factor Q and shape factors sf. We demonstrate Janus rings form polymorphic micelles that vary from a spherical shape, akin to that known for linear block copolymers, to a novel type of toroidal shape, and we highlight the role played by the key physical parameters leading to the stabilization of such structures.

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“…Huang et al observed an apparent correspondence between the high-rate extensional viscosity η ex of ring and linear melts of Polystyrene (PS) with the same M w = 185 kg/mol, leading them to propose that rings transition to behaving like linear chains as they elongate [7]. However, prior simulation studies of unentangled ring and linear melts under planar extension did not observe a clear correspondence at large W i [12].…”

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confidence: 99%

“…Prior studies on this bead-spring model have measured τ e ≈ 1.98 × 10 3 [14]. Figure 2 plots the normalized extensional viscosity η ex /η N ex versus reduced time t/τ ring for a bead-spring melt of rings alongside the experimental curves from Huang et al [7]. Both simulation and experiment use 52.…”

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confidence: 99%

Topological Linking Drives Anomalous Thickening of Ring Polymers in Weak Extensional Flows

O'Connor

Rubinstein

et al. 2020

Phys. Rev. Lett.

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Molecular dynamics simulations confirm recent extensional flow experiments showing ring polymer melts exhibit strong extension-rate thickening of the viscosity at Weissenberg numbers W i << 1. Thickening coincides with the extreme elongation of a minority population of rings that grows with W i. The large susceptibility of some rings to extend is due to a flow-driven formation of topological links that connect multiple rings into supramolecular chains. Links form spontaneously with a longer delay at lower W i and are pulled tight and stabilized by the flow. Once linked, these composite objects experience larger drag forces than individual rings, driving their strong elongation. The fraction of linked rings depends non-monotonically on W i, increasing to a maximum when W i ∼ 1 before rapidly decreasing when the strain rate approaches 1/τe. arXiv:1910.14666v1 [cond-mat.soft]

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Unexpected Stretching of Entangled Ring Macromolecules

Cited by 91 publications

References 41 publications

Stretching of Bombyx mori Silk Protein in Flow

Stretching of Bombyx mori Silk Protein in Flow

Aggregation shapes of amphiphilic ring polymers: from spherical to toroidal micelles

Topological Linking Drives Anomalous Thickening of Ring Polymers in Weak Extensional Flows

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