Preparation and properties of polyrotaxane from α-cyclodextrin and poly(ethylene glycol) with poly(vinyl alcohol)

alpha-Cyclodextrin (alpha-CD) was found to form inclusion complexes with poly(ethylene glycol) (PEG) having a crystalline state in high yields, which have been investigated extensively in the past. Formation of an inclusion complex depends strongly on structure, molecular weight and geometry of the polymer. Development of a dicomponent inclusion complex (DIC) of PEG and alpha-CD in the presence of poly(vinyl alcohol) (PVA) and initiation of hexagonal crystals upon sonication have exhibited various microstructures. Formation of the new inclusion complex in PVA heavily depends on the concentration of PVA, temperature and sonication time. The complexes produced are characterized by FTIR, HNMR spectra and powder X-ray. (HNMR)-H-1 of the complexes demonstrate that their stoichiometric ratio is 2:1 (two ethylene glycol units and one alpha-CD). X-ray patterns of PEG-alpha-CD complex indicate that the alpha-CD forms channels whereas PEG/alpha-CD/PVA creates cage-type structures.