Supramolecular Hybrid Structures and Gels from Host-Guest Interactions between α-Cyclodextrin and PEGylated Organosilica Nanoparticles.

Polypseudorotaxanes are polymer chains threaded by molecular rings that are free to unthread; these "pearl-necklace" can self-assemble further, leading to higher-order supramolecular structures with interesting functionalities. In this work, the complexation between α-cyclodextrin (α-CD), a cyclic oligosaccharide of glucopyranose units, and poly(ethylene glycol) (PEG) grafted to silica nanoparticles was studied. The threading of α-CD onto the polymeric chains leads to their aggregation into bundles, followed by either the precipitation of the inclusion complex or the formation of a gel phase, in which silica nanoparticles are incorporated.