分子ネックレスを用いた動的架橋高分子ゲル・エラストマーの力学・破壊物性

抄録

We review mechanical and fracture properties of gels and elastomers containing polyrotaxane, necklace-like supramolecular assembly in which axial polymer chain is threaded through ring molecules. By cross-linking ring molecules of different polyrotaxanes in solution, polymer chains are cross-linked by figure-of-eight cross-links and the obtained polymer networks are called slide-ring (SR) gels. The unique feature of SR gels is that the cross-linking points consisting of two rings can slide on polymer chains and chain length between cross-links changes with macroscopic deformation. From our crack propagation tests on SR gels with different structural parameters (cross-linking density, axial chain length, and ring coverage on polymer), we have found that the sliding of the movable cross-links enhances their mechanical toughness without any reduction of stiffness (Young's modulus). The slide-ring concept also can be applied to polymer gels and elastomers cross-linked by small amount of polyrotaxane cross-linkers.