Sliding mode of cyclodextrin in polyrotaxane and slide-ring gel

The sliding modes of cyclic molecules in polyrotaxane and of cross-linking junctions in topological gel or slide-ring gel were investigated by quasi-elastic light scattering. We found that a polyrotaxane sparsely including α-cyclodextrin showed the sliding mode in solution other than the self- and cooperative-diffusion modes whereas the sliding mode was not observed in a polyrotaxane densely including α-cyclodextrin. After gelation of the sparse polyrotaxane, the self-diffusion mode of the polyrotaxane disappeared but the sliding mode was still observed. This indicated that the figure-of-eight cross-links in the slide-ring gel slid in the polymer network, passing through the polymer chains.