Loose-Fit Polypseudorotaxanes Fabricated by γ-CDs Threaded Onto a Single PNIPAAm-PEG-PNIPAAm Chain in Aqueous Solution

When ?-CDs are added to an aqueous solution of PNIPAAm-b-PEG-b-PNIPAAm block copolymer, they are threaded onto the polymer chains to give loose-fit polypseudorotaxanes (PPRs). The inclusion complexation shows a marked dependence on the length of the PNIPAAm blocks although the threaded ?-CDs are preferably located on the central PEG block. The structure of the resulting PPRs is characterized by using XRD, 1H and 13C CP/MAS NMR, TGA FTIR, and DSC analyses. Because of the mismatched fit between the guest polymer chain and the cavity of the host ?-CDs, these PPRs may be promising in applications as solid stimuli-responsive materials.