Volume 79, Number 6, September 2007
Article Number 66004
Number of page(s) 4
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 21 August 2007
EPL, 79 (2007) 66004
DOI: 10.1209/0295-5075/79/66004

Dielectric relaxation of liquid-crystalline polyrotaxane

A. Inomata1, H. Ishibashi1, T. Nakajima1, Y. Sakai1, M. Kidowaki1, 2, T. Shimomura3 and K. Ito1, 2

1  Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8561, Japan
2  CREST, Japan Science and Technology Agency (JST) - 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
3  Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology - Koganei, Tokyo 184-8588, Japan

received 12 April 2007; accepted in final form 1 August 2007; published September 2007
published online 21 August 2007

A new supramolecular system, liquid-crystalline polyrotaxane (LCPR), has been recently prepared by introduction of 4-cyano-$4^\prime $-n-pentylbiphenyl (5CB) groups to the cyclic molecules of a polyrotaxane (PR) consisting of polyethylene glycol (PEG) and $\alpha $-cyclodextrin ($\alpha $-CD). Here we measured and compared the dielectric relaxations of PR and LCPR in solid state to investigate molecular motions of $\alpha $-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 $\alpha $-CD along the axis chain and that the other mode in LCPR should arise from the rotational fluctuation of $\alpha $-CD modified by 5CB.

61.30.Vx - Polymer liquid crystals.
77.22.Gm - Dielectric loss and relaxation.

© Europhysics Letters Association 2007