Volume 54, Issue 21 pp. 6168-6172
Communication

Mechanophores with a Reversible Radical System and Freezing-Induced Mechanochemistry in Polymer Solutions and Gels

Dr. Keiichi Imato

Dr. Keiichi Imato

Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

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Atsushi Irie

Atsushi Irie

Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

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Takahiro Kosuge

Takahiro Kosuge

Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

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Dr. Tomoyuki Ohishi

Dr. Tomoyuki Ohishi

Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

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Dr. Masamichi Nishihara

Dr. Masamichi Nishihara

Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

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Prof. Atsushi Takahara

Corresponding Author

Prof. Atsushi Takahara

Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

Atsushi Takahara, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

Hideyuki Otsuka, Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

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Prof. Hideyuki Otsuka

Corresponding Author

Prof. Hideyuki Otsuka

Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

Atsushi Takahara, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

Hideyuki Otsuka, Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

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First published: 30 March 2015
Citations: 239

This work was supported by the Funding Program for Next Generation World-Leading Researchers (No. GR077) from Japan Society of the Promotion of Science (JSPS), JSPS KAKENHI (No. 26288057 and No. 26620175), and JSPS Research Fellowships for Young Scientists (No. 24⋅7074).

Graphical Abstract

Freezing-induced mechanochemistry: A new diarylbibenzofuranone-based mechanophore showed reversible color change by external forces through radical mechanism. By incorporating the mechanophore into polymer chains, it was revealed that freezing gels induced mechanical force along the chains, but the force was not large enough to cleave common covalent bonds.

Abstract

Visualization and quantitative evaluation of covalent bond scission in polymeric materials are highly important for understanding failure, fatigue, and deterioration mechanisms and improving the lifetime, durability, toughness, and reliability of the materials. The diarylbibenzofuranone-based mechanophore radical system enabled, through electron paramagnetic resonance spectroscopy, in situ quantitative evaluation of scission of the mechanophores and estimation of mechanical energy induced along polymer chains by external forces. The coagulation of polymer solutions by freezing probably generated force but did not cleave the mechanophores. On the other hand, cross-linking led to efficient propagation of the force of more than 80 kJ mol−1 to some mechanophores, resulting their cleavage and generation of colored stable radicals. This mechanoprobe concept has the potential to elucidate other debated issues in the polymer field as well.

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