1. Department of Polymer Science & Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan; Asahikasei Chemicals Co., Yako, Kawasaki-ku, Kawasaki 210-0863, Japan; and Department of Materials Science, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan