Repeatable mechanochemical activation of dynamic covalent bonds in thermoplastic elastomers

Imato, Keiichi; Kanehara, Takeshi; Nojima, Shiki; Ohishi, Tomoyuki; Higaki, Yasuki; Takahara, Atsushi; Otsuka, Hideyuki

doi:10.1039/c6cc04767j

Cited by 78 publications

(67 citation statements)

References 46 publications

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“…Examples of physical mechanochromism include rapture of dye‐containing microcapsules, load‐dependent spacing of layers of photonic crystals, phase transitions, aggregation and conformational changes . Chemical mechanochromism requires a reaction, such as load‐dependent equilibria between aggregates and isolated molecules of certain aromatic dyes or between spyropyran and merocyanine isomers, or load‐accelerated thermal dissociations of 1,2‐dioxetane derivatives, which transiently creates chemiluminescence, of hexaarylbisimidazole, diarylbibenzofuranone, dianthracene or dicinnamate derivatives (Figure ). Proposed or realized applications of mechanochromic materials include autonomous indicators of mechanical damage, camouflage, security paper and labels, optical storage and fundamental studies of polymer adhesion, friction, crack propagation and plastic flow.…”

Section: Mechanochemistry Of Polymers In Solidsmentioning

confidence: 99%

Experimental Polymer Mechanochemistry and its Interpretational Frameworks

2017

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Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non‐equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self‐strengthening and stress‐reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose solution may have a disproportionate impact on the development of polymer mechanochemistry.

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Section: Mechanochemistry Of Polymers In Solidsmentioning

confidence: 99%

Experimental Polymer Mechanochemistry and its Interpretational Frameworks

2017

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“…(b)] . Performing tensile deformation in multiple cycles showed a repeated coloration and fading of the mechanophores and the amount of stress in the samples could be quantified by means of in situ electron paramagnetic resonance measurements …”

Section: Mechanically Induced Cleavage Of Covalent and Noncovalent Bondsmentioning

confidence: 99%

“…112 Performing tensile deformation in multiple cycles showed a repeated coloration and fading of the mechanophores and the amount of stress in the samples could be quantified by means of in situ electron paramagnetic resonance measurements. 113 Structural motifs that respond to mechanical stimulation through the emission of light were pioneered by Sijbesma and coworkers, 114 who incorporated a bis(adamantyl)-1,2dioxetane in the center of poly(methyl acrylate). Mechanical activation in solution by means of sonication caused a pericyclic reaction of the strained four-membered ring, concomitant with bright-blue luminescence.…”

Section: Journal Of Polymer Sciencementioning

confidence: 99%

Approaches to polymeric mechanochromic materials

Calvino

Neumann

Weder

et al. 2016

J. Polym. Sci. Part A: Polym. Chem.

133

129

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Mechanochromic materials respond to mechanical stimuli with a change of their optical properties. Such materials are of interest for many technological applications and support fundamental research as they help improving the understanding of stress transfer in polymeric objects and aid in the identification of the processes that lead to mechanical failure. In this highlight, different approaches are discussed that permit the design of polymeric materials, which signal mechanical stresses through a chromic response. This highlight emphasizes materials that exhibit mechanically induced changes of their intrinsic absorption or emission properties. These responses almost exclusively originate from changes of molecular structure, conformational rearrangements, or disruption of intermolecular interactions. V C 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 640-652

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“…Using as cross‐linker diarylbibenzofuranone (DABBF), the dimer of arylbenzofuranone (ABF, analog to widely used commercial product HP‐136), the polymer gel synthesized was able to undergo self‐healing under mild conditions at room temperature, due to the dynamic covalent bond in its structure. In fact, this crosslinker had already been studied because of its anomalous behavior and antioxidant character (persistent carbon‐centered radical), and for its mechanochromic properties as well . To correctly apply this crosslinker in a variety of systems, understanding and describing the structural and electronic influence in its properties is crucial.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, this crosslinker had already been studied because of its anomalous behavior and antioxidant character (persistent carbon-centered radical), [48] and for its mechanochromic properties as well. [49][50][51][52] To correctly apply this crosslinker in a variety of systems, understanding and describing the structural and electronic influence in its properties is crucial. In fact, previous works have highlighted the importance of wider studies of the self-healing behavior, [53,54] especially through theoretical simulations and characterization.…”

Section: Introductionmentioning

confidence: 99%

Dynamic covalent bond from first principles: Diarylbibenzofuranone structural, electronic, and oxidation studies

2017

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A structure that can self-heal under standard conditions is a challenge faced nowadays and is one of the most promising areas in smart materials science. This can be achieved by dynamic bonds, of which diarylbibenzofuranone (DABBF) dynamic covalent bond is an appealing solution. In this report, we studied the DABBF bond formation against arylbenzofuranone (ABF) and O reaction (autoxidation). Our results show that the barrierless DABBF bond formation is preferred over autoxidation due to the charge transfer process that results in the weakly bonded superoxide. We calculated the electronic and structural properties using total energy density functional theory. © 2017 Wiley Periodicals, Inc.

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Repeatable mechanochemical activation of dynamic covalent bonds in thermoplastic elastomers

Cited by 78 publications

References 46 publications

Experimental Polymer Mechanochemistry and its Interpretational Frameworks

Experimental Polymer Mechanochemistry and its Interpretational Frameworks

Approaches to polymeric mechanochromic materials

Dynamic covalent bond from first principles: Diarylbibenzofuranone structural, electronic, and oxidation studies

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