Chameleon-like elastomers with molecularly encoded strain-adaptive stiffening and coloration

Vatankhah-Varnosfaderani, Mohammad; Keith, Andrew N.; Cong, Yidan; Liang, Heyi; Rosenthal, Martin; Sztucki, Michael; Clair, Charles; Magonov, Sergei; Ivanov, Dimitri A.; Dobrynin, Andrey V.; Sheiko, Sergei S.

doi:10.1126/science.aar5308

Cited by 385 publications

(490 citation statements)

References 57 publications

(46 reference statements)

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“…[68] Therefore, another important parameter affecting the network shear modulus is the crosslink density, [7,24,33,34,69] or the DP of the bottlebrush backbone between crosslinks, n x . These elastomers have intrinsic supersoft and superelastic properties without additional solvents and are promising candidates for synthetic substitutes of biological tissues.…”

Section: Diluted Plateau Shear Modulusmentioning

confidence: 99%

Comb and Bottlebrush Polymers with Superior Rheological and Mechanical Properties

2019

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combined with the grafting-to method [1,10] results in comb polystyrenes (PSs) with well-entangled monodisperse backbone and side chains; however, branch points along the backbone are randomly distributed. This random distribution of branch points has no distinct effect on the rheological properties of dense comb topologies; however, it will broaden the backbone relaxation time of loose comb topologies even though the molecular weight distribution is narrow enough. [11] A controlled branching point spacing can be achieved through the coupling of living macroanions; [12] however, this method is prone to slightly high molecular weight distribution, Ð > 1.5. Synthesis of welldefined densely grafted bottlebrushes using ROMP and grafting-through method guarantees the presence of one side chain per repeating unit on the backbone. Bottlebrushes with more than one branch per backbone repeating unit can also be synthesized using ROMP and macromonomers with more bulky groups referred as wedge polymers. [13] These bottlebrushes are similar to that of the dendronized polymer with only one layer of grafting. Loosely grafted bottlebrushes with longer distance between the branching points can be achieved using ROMP technique through copolymerization of macromonomer and a diluent molecule, e.g., racemic endo,exo-norbornenyl diesters, with different ratios. However, different reactivity of macromonomer and diluent leads to a gradient of branching point spacing along the backbone, [14] where the conformations of side chains along the backbone are affected by this gradient. [15] It should be mentioned that the bottlebrushes synthesized with ROMP technique have different repeating units in the backbone than the side chains which might cause microphase separation. However this issue could be ignorable in dense bottlebrushes where the volume fraction of backbone is less than 1 wt%. In order to avoid any microphase separation, Sheiko and co-workers [16] synthesized a series of dense combs and loose bottlebrushes homo poly(n-butyl acrylates) (PBA) with similar side chains and systematically varied grafting density through copolymerization of nonfunctional n-butyl acrylates with trimethylsilyl-protected acrylates by ATRP. However, in order to achieve high degree of polymerization (DP) of backbone (entangled system) for dense bottlebrushes, they had to use slightly different backbones, i.e., poly(n-butyl methacrylate). An organometallic coordinative insertion polymerization of α-olefins results in entangled densely grafted bottlebrushes with rod-like side chains where both backbone and side chains have alkane groups. However the dispersity index of such homopolymer bottlebrushes would Comb and bottlebrush polymers present a wide range of rheological and mechanical properties that can be controlled through their molecular characteristics, such as the backbone and side chain lengths as well as the number of branches per molecule or the grafting density. This review investigates the impact of these characteristics specifically on the zero sh...

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Section: Diluted Plateau Shear Modulusmentioning

confidence: 99%

Comb and Bottlebrush Polymers with Superior Rheological and Mechanical Properties

2019

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“…In these solvent‐free polymer networks, the network strands (bottlebrush backbones) are effectively swollen by the low T g bottlebrush sidechains, leading to low moduli comparable to conventional solvent‐containing gels. These materials demonstrate stress‐strain behaviors resembling a variety of biological tissues and hold great promise for biomaterial applications …”

Section: Basic Properties Of Polymer Networkmentioning

confidence: 99%

Polymer Networks: From Plastics and Gels to Porous Frameworks

2020

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Polymer networks, which are materials composed of many smaller components—referred to as “junctions” and “strands”—connected together via covalent or non‐covalent/supramolecular interactions, are arguably the most versatile, widely studied, broadly used, and important materials known. From the first commercial polymers through the plastics revolution of the 20th century to today, there are almost no aspects of modern life that are not impacted by polymer networks. Nevertheless, there are still many challenges that must be addressed to enable a complete understanding of these materials and facilitate their development for emerging applications ranging from sustainability and energy harvesting/storage to tissue engineering and additive manufacturing. Here, we provide a unifying overview of the fundamentals of polymer network synthesis, structure, and properties, tying together recent trends in the field that are not always associated with classical polymer networks, such as the advent of crystalline “framework” materials. We also highlight recent advances in using molecular design and control of topology to showcase how a deep understanding of structure–property relationships can lead to advanced networks with exceptional properties.

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“…In diesen lösungsmittelfreien Polymernetzwerken sind die Stränge des Netzwerks (Flaschenbürsten‐Gerüst) durch die Flaschenbürsten‐Seitenketten mit niedrigem T g ‐Wert wirksam gequollen, was zu einem niedrigen Modul im Vergleich zu herkömmlichen lösungsmittelhaltigen Gelen führt. Diese Materialien zeigen ein ähnliches Spannungs‐Dehnungs‐Verhalten wie viele biologische Gewebe und sind vielversprechend für Biomaterialanwendungen …”

Section: Grundlegende Eigenschaften Von Polymernetzwerkenunclassified

“…Diese Materialien zeigen ein ähnliches Spannungs-Dehnungs-Verhalten wie viele biologische Gewebe [131] und sind vielversprechend fürB iomaterialanwendungen. [132]…”

Section: Angewandte Chemieunclassified

Polymernetzwerke: Von Kunststoffen und Gelen zu porösen Gerüsten

Zhao

Johnson

2020

Angewandte Chemie

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Polymernetzwerke sind Materialien, die aus vielen kleineren Komponenten aufgebaut sind, die als “Vernetzungspunkte” und “Stränge” bezeichnet werden und über kovalente oder nichtkovalente/supramolekulare Wechselwirkungen miteinander verknüpft sind. Sie gehören zu den vielseitigsten, am häufigsten eingesetzten und wichtigsten Materialien. Von den ersten kommerziellen Polymeren über die Kunststoffrevolution des 20. Jahrhunderts bis in die Gegenwart gibt es nahezu keine Aspekte des modernen Lebens, die nicht von Polymernetzwerken beeinflusst werden. Dennoch müssen noch viele Herausforderungen in Angriff genommen werden, um ein vollständiges Verständnis dieser Materialien zu ermöglichen und ihre Entwicklung für künftige Anwendungen zu fördern, die von Energie‐Harvesting und Energiespeicherung bis zur Gewebezüchtung und additiven Fertigung reichen. Hier geben wir einen Überblick über die Grundlagen der Synthese, Struktur und Eigenschaften von Polymernetzwerken, unter Einbeziehung aktueller Trends auf dem Gebiet. Wir werden außerdem die neuesten Fortschritte bei der Anwendung des Moleküldesigns und der Steuerung der Topologie aufzeigen, um zu demonstrieren, wie ein tiefgehendes Verständnis der Struktur‐Eigenschaft‐Beziehungen zu hochentwickelten Netzwerken mit außergewöhnlichen Eigenschaften führen kann.

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Chameleon-like elastomers with molecularly encoded strain-adaptive stiffening and coloration

Cited by 385 publications

References 57 publications

Comb and Bottlebrush Polymers with Superior Rheological and Mechanical Properties

Comb and Bottlebrush Polymers with Superior Rheological and Mechanical Properties

Polymer Networks: From Plastics and Gels to Porous Frameworks

Polymernetzwerke: Von Kunststoffen und Gelen zu porösen Gerüsten

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