Formation of Inclusion Complexes of Poly(hexafluoropropyl ether)s with Cyclodextrins

Cyclodextrins (CDs) have been found to form pseudo-polyrotaxanes (CDs⊃pFPEs) with poly(hexafluoropropyl ether)s (pFPEs) by mixing bulk pFPEs with aqueous solutions of CDs. The mixture of γCD with α,ω-diol-pFPE (pFPE-H) gave γCDs⊃pFPE-H in 86% yield, which was higher than those of βCD (47%) or αCD (2.4%). In contrast, the mixture of γCD with α,ω-dicarboxylic acid-pFPE (pFPE-C) gave γCDs⊃pFPE-C in a moderate yield (66% yield), but higher threading ratio (80%). The threading ratio of CDs⊃pFPEs depends on the hydrophilicity of the functional end group of pFPEs. The hydrophilic and hydrophobic balance of pFPEs plays an important role to form CDs⊃pFPEs.