Self-Healing Materials Formed by Cross-Linked Polyrotaxanes with Reversible Bonds

Self-Healing Materials Formed by Cross-Linked Polyrotaxanes with Reversible Bonds

Masaki Nakahata, Shoko Mori, Yoshinori Takashima, Hiroyasu Yamaguchi, Akira Harada3,correspondencePress enter key for correspondence informationemailPress enter key to Email the author

DOI: http://dx.doi.org/10.1016/j.chempr.2016.09.013

source cell.com

Highlights

•Polyrotaxanes and vinyl polymers cross-linked by reversible bonds

•Interplay of movable cross-links and reversible bonds realizes self-healing

•Rapid and efficient self-healing in hydrogel and semi-dry states

The Bigger Picture

Maintenance-free materials with self-healing ability are highly desirable for extending the lifespan of materials. Here, we report on self-healing materials based on polyrotaxane cross-linked by reversible bond formation between ring molecules and vinyl polymers. With the use of polyrotaxane, the mobility arising from the sliding motion of the ring molecules along the axle polymer accelerates self-healing. Compared with conventional types, a coating film composed of polyrotaxane-based self-healing materials shows rapid and effective self-healing from external damage. This research opens up a new design principle of self-healing materials for a sustainable society.

Summary

Self-healing materials based on polymer gels composed of polyrotaxane and poly(acrylamide) cross-linked with boronate linkages were synthesized and characterized. These gels combine dynamic covalent bonds with a sliding motion of functional molecules, wherein the mobility of the ring molecules along the axle in the polyrotaxane and the sliding nature of the cross-linker are thought to impart self-healing properties on the resultant materials. Both the gel state and the dried gel state exhibit rapid and efficient self-healing properties. On the basis of the self-healing property of the dried gel, a scratch-healing top coating for hard materials was prepared by a photocuring method. A coating of the self-healing material on glass demonstrates the ability to recover from a scratch mark to its initial state under semi-dry conditions.

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http://www.cell.com/chem/abstract/S2451-9294(16)30158-9

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