New solvent for polyrotaxane. II. Dissolution behavior of polyrotaxane in ionic liquids and preparation of ionic liquid-containing slide-ring gels

The dissolution behavior of polyrotaxanes, consisting of a-cyclodextrin and poly(ethylene glycol), with different molecular weights (2000 and 35,000) was investigated. Halogen-containing ionic liquids, such as chlorides or bromides, were found to be good solvents for polyrotaxanes, regardless of their cations. Dissolution required a high temperature (above 90 degrees C), while intensive heating over 105 degrees C seemed to cause decomposition of the polyrotaxane. The discovery of new solvents for polyrotaxane was applied in the preparation of ionic liquid-containing slide-ring gels (SR gels), that is supramolecular networks of polyrotaxane swollen with ionic liquids, using a devised "non-drying" technique accompanied by solvent exchange. Significant swelling of the SR gels with the ionic liquids was confirmed by dynamic mechanical measurements. (c) 2006 Wiley Periodicals, Inc.