Loose-Fit polypseudorotaxanes fabricated by Iγ-CDs threaded onto a single PNIPAAm-PEG-PNIPAAm chain in aqueous solution

When Iγ-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 Iγ-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 Iγ-CDs, these PPRs may be promising in applications as solid stimuli-responsive materials. Novel loose-fit polypseudorotaxanes are prepared by self-assembly of Iγ-CDs with a PNIPAAm-PEG-PNIPAAm block copolymer in aqueous solution. The inclusion complexation process depends on the length of the terminating PNIPAAm blocks, and the threaded Iγ-CDs are preferably located on the central PEG block.