Universal Cyclic Topology in Polymer Networks

Wang, Rui; Alexander‐Katz, Alfredo; Johnson, Jeremiah A.; Olsen, Bradley D.

doi:10.1103/physrevlett.116.188302

Cited by 108 publications

(139 citation statements)

References 43 publications

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“…5D), they still have cyclic defects such as secondary loops (51). We have previously shown that the number of 1°loops is coupled to the numbers of higher order loops (48), and that these higher order defects are also elastically defective (12). We suspected that STF addition may reduce higher order loop defects in Tetra-PEG gels (45).…”

Section: Generality Of Stf Additionmentioning

confidence: 96%

“…(F) Representative tensile testing measurements of gels prepared at B 4 = 5 mM using batch addition and STF addition with 15% versus 50% of B 4 added slowly. suggest that inversing the order of addition leads to new defects [e.g., clusters of variable network density (46,47) or higher order loops (12,48)] that cancel the effect of reducing ϕ λ . SANS analysis is consistent with this hypothesis: the mesh size for this gel was larger (4.32 ± 0.05 nm; SI Appendix , Table S11) than that for the batch-addition sample (2.83 ± 0.05 nm) despite its lower fraction of 1°loops.…”

Section: Monomer Feed Rate and Network Topologymentioning

confidence: 99%

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Semibatch monomer addition as a general method to tune and enhance the mechanics of polymer networks via loop-defect control

Kawamoto

Zhong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Controlling the molecular structure of amorphous cross-linked polymeric materials is a longstanding challenge. Herein, we disclose a general strategy for precise tuning of loop defects in covalent polymer gel networks. This "loop control" is achieved through a simple semibatch monomer addition protocol that can be applied to a broad range of network-forming reactions. By controlling loop defects, we demonstrate that with the same set of material precursors it is possible to tune and in several cases substantially improve network connectivity and mechanical properties (e.g., ∼600% increase in shear storage modulus). We believe that the concept of loop control via continuous reagent addition could find broad application in the synthesis of academically and industrially important cross-linked polymeric materials, such as resins and gels.

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Section: Generality Of Stf Additionmentioning

confidence: 96%

Section: Monomer Feed Rate and Network Topologymentioning

confidence: 99%

Semibatch monomer addition as a general method to tune and enhance the mechanics of polymer networks via loop-defect control

Kawamoto

Zhong

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…The fractions x i of cyclic defects (small fragments of the network with i 1 "internal" cross-links) depend on the type of reactions leading to the formation of the network [23,24]. All x i universally depend on one dimensionless parameter x 1 characterizing the conditions for network preparation [25]. The primary loops with concentration x 1 are tied to the network at only one crosslink.…”

Section: Finite-size Loops Of Real Networkmentioning

confidence: 99%

Theory of Flexible Polymer Networks: Elasticity and Heterogeneities

Panyukov

2020

Polymers

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A review of the main elasticity models of flexible polymer networks is presented. Classical models of phantom networks suggest that the networks have a tree-like structure. The conformations of their strands are described by the model of a combined chain, which consists of the network strand and two virtual chains attached to its ends. The distribution of lengths of virtual chains in real polydisperse networks is calculated using the results of the presented replica model of polymer networks. This model describes actual networks having strongly overlapping and interconnected loops of finite sizes. The conformations of their strands are characterized by the generalized combined chain model. The model of a sliding tube is represented, which describes the general anisotropic deformations of an entangled network in the melt. I propose a generalization of this model to describe the crossover between the entangled and phantom regimes of a swollen network. The obtained dependence of the Mooney-Rivlin parameters C 1 and C 2 on the polymer volume fraction is in agreement with experiments. The main results of the theory of heterogeneities in polymer networks are also discussed.

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“…With respect to a correlation between intrinsic electrical breakdown strength and the Young's modulus, the model cannot in the present state provide a universal, coherent picture of the relationship, since filler–filler and filler–polymer interactions, as well as polymer entanglements, are not accounted for in the model. Entanglements do not contribute to any changes in the derived equations, but they do contribute strongly to the Young's modulus in a nonlinear way . However, for entanglement‐ and filler‐free elastomers such as the recently developed cross‐linked polymer brushes, a relationship can be derived .…”

Section: Details On the Investigated Elastomers Of Figurementioning

confidence: 99%

Molecular Strategies for Improved Dielectric Elastomer Electrical Breakdown Strengths

Skov

2018

Macromol. Rapid Commun.

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Dielectric elastomer transducers (actuators and generators) possess great commercial potential because they allow for novel transducer designs and applications due to-amongst others-their flexibility and low weight. On the other hand, the flexibility and inherent softness of dielectric elastomers also pose restrictions on their use, since the thin elastomers may undergo destructive deformations under large loads or in large electrical fields. In order to design better dielectric elastomers, it is crucial to understand the underlying phenomena of how thin and elastic dielectric elastomer films undergo electrical breakdown. This understanding will allow for the design of dielectric elastomers with high electrical breakdown strength and thus open up the use of films in transducers at higher electrical fields and forces. Here, the study couples intrinsic electrical breakdown strengths with well-described polymer and network characteristics, namely Kuhn parameters and cross-linking density. The universality of the developed model is illustrated by comparison over a wide range of silicone-based elastomers, such as prestretched elastomers and synthesized cross-linked bottlebrush polymers, representing both filled and unfilled elastomers. This study paves a robust way for the molecular design of elastomers into high-intrinsic electrical breakdown strength dielectric elastomers.

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Universal Cyclic Topology in Polymer Networks

Cited by 108 publications

References 43 publications

Semibatch monomer addition as a general method to tune and enhance the mechanics of polymer networks via loop-defect control

Semibatch monomer addition as a general method to tune and enhance the mechanics of polymer networks via loop-defect control

Theory of Flexible Polymer Networks: Elasticity and Heterogeneities

Molecular Strategies for Improved Dielectric Elastomer Electrical Breakdown Strengths

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