From Topological Gels to Slide-Ring Materials

A novel type of gel, called a topological gel, has been recently developed with a supramolecular architecture with topological characteristics. In the topological gel, polymer chains with bulky end groups are neither covalently crosslinked as in chemical gels nor attractively interacting as in physical gels but are topologically interlocked by figure-eight shaped crosslinks. Hence, these crosslinks can pass along the polymer chains freely to equalize the tension of the threading polymer chains similarly to pulleys; this is called the pulley effect. This concept can be applied not only to gels but also to a wide variety of polymeric materials without solvents. Then, polymeric materials with movable crosslinks are referred to as slide-ring materials (SRMs) in a wider sense. Here, we review the synthesis, structure, physical properties, and applications of topological gels and SRMs. In particular, slide-ring elastomers show remarkable scratch-proof properties for application to coating materials for automobiles, cell phones, mobile computers, golf clubs, and so on. (c) 2014 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40509.