42 research outputs found
Dielectric relaxation of liquid-crystalline polyrotaxane
A new supramolecular system, liquid-crystalline polyrotaxane (LCPR), has
been recently prepared by introduction of 4-cyano--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