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A series of highly dielectric polyrotaxane derivatives consisting of axle polyethylene glycol (PEG) and threated α-cyclodextrins (CDs) were synthesized by modifying the hydroxyl groups of CDs with cyanoethyl or dicyanobutyl groups. We found that the introduction of poly(2-hydroxyethyl methacrylate) (PHEMA) side chain with a number of hydroxyl groups and subsequent cyanoethylation give particularly high dielectric constant (23.4), which is comparable to those of commercially available highly dielectric polymeric materials. We also succeeded in preparing a highly dielectric (e′ ∼ 16 at 10 kHz) and flexible (Young's modulus ∼ 3.4 MPa) elastomer film without any inorganic filler, which is a desirable material for insulator of dielectric elastomer actuators.

We investigated the structure, thermal properties, and dynamics of polyrotaxane (PR), composed of poly(ethylene glycol) (PEG) and α-cyclodextrins (CDs), and PR derivatives comprising hydroxypropylated CDs, that is, hydroxypropylated PRs (HyPRs), in the solid state by using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), and viscoelastic spectroscopy. It was observed that HyPRs with high chemical modification ratios show a WLF-type viscoelastic relaxation that can be ascribed to the cooperative segmental motion of several CD molecules, whereas HyPRs with a lower modification ratio and PR with a highly ordered packing structure of CDs do not exhibit any mechanical relaxation mode. A comparison between the relaxation temperatures of HyPRs with different modification and inclusion ratios suggested that the hydrogen bond between CDs primarily dominates the viscoelastic properties of solid-state PR. Our experimental results indicate a close relationship between the crystallinity and...

A novel side-chain liquid crystalline polyrotaxane (LCPR) whose mesogenic side chains can slide and rotate on the linear backbone was first developed. To obtain the LCPR, 6-(4‘-cyanobiphenyl-4‘ ‘-yloxy)hexanoyl chloride was prepared and reacted with a polyrotaxane consisting of α-cyclodextrin, poly(ethylene glycol) (Mw = 35 000), and adamantane end groups. The molecular characterization of the LCPR was performed with FT-IR, 1H NMR, and gel permeation chromatography analysis. Its phase structures and transitions were investigated by differential scanning calorimetry, wide-angle X-ray diffraction, and polarized light microscopy experiments. The experimental results shows that the LCPR has glass transition at 70 °C and mesomorphic−isotropic transition at 129 °C.

A new supramolecular system, liquid-crystalline polyrotaxane (LCPR), has been recently prepared by introduction of 4-cyano-4'-n-pentylbiphenyl (5CB) groups to the cyclic molecules of a polyrotaxane (PR) consisting of polyethylene glycol (PEG) and α-cyclodextrin (α-CD). Here we measured and compared the dielectric relaxations of PR and LCPR in solid state to investigate molecular motions of α-CD in PR and LCPR. It was found that PR exhibited a single relaxation mode while LCPR had two modes. These results suggested that the relaxation mode in PR would be due to the sliding fluctuation of α-CD along the axis chain and that the other mode in LCPR should arise from the rotational fluctuation of α-CD modified by 5CB.