1. Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
2. Advanced Science Research Center (ASRC), Japan Atomic Energy Agency (JAEA), Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan,
3. Research Center, TOYOBO Co., Ltd., 2-1-1 Katata, Ohtsu-shi, Shiga 520-0292, Japan