A Supramolecular Chiroptical Switch Using an Amorphous Azobenzene Polymer

Authors

  • M. J. Kim,

    1. Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea
    2. International Center for Young Scientists (ICYS), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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  • S. J. Yoo,

    1. Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea
    2. Present address: Research Center for Energy Conversion and Storage, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea
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  • D. Y. Kim

    1. Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea
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  • This work was financially supported by the Ministry of Commerce, Industry and Energy (MOCIE) of Korea, the BK-21 project, National Research Laboratory program of KOSEF, and Special Coordination Funds for Promoting Science and Technology from MEXT, Japan.

Abstract

Supramolecular chirality has been optically induced in an achiral epoxy-based polymer containing photoresponsive azobenzene groups. The origin of this effect is the long-range helical arrangement of the azobenzenes, which extends through the entire thickness of the film. The helicity induced by the handedness of the laser can be reversibly switched by alternately exposing the film to a 488 nm laser with right- and left-handed elliptical polarization. The chiral properties of these films have been characterized by circular dichroism spectroscopy and optical rotation. After five switching cycles, the fatigue resistance is seen to depend on the absorption wavelength of the film, probably due to differences in the photoresponsive speed of the azobenzenes and the polymeric segments.

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