Photoresponsive slide-ring gel

Slide-ring topological gels with mobile cross-linking units are a new class of soft materials that exhibit distinct features differing from those of conventional chemically or physically crosslinked gels. Photoresponsive behavior arising from the dynamic nature of the cross-linkers is demonstrated for a slide-ring, gel prepared by adding azobenzene units to the mobile a-cyclodextrin units of a poly(ethylene oxide)based polyrotaxane (see figure).