1. Laboratoire de Chimie des Polymères Organiques, Université de Bordeaux, CNRS, ENSCPB, 16 avenue Pey Berland, 33607 Pessac Cedex, France
2. Division of Soft Material Chemistry, Polymeric and Organic Materials Department, Graduate School of Science and Engineering, Tokyo Institute of Technology, S1-6, 2-12-1, Ohokayama, Meguro-ku, Tokyo 152-8552, Japan