1. Joint Research Center for Precision Polymerization, Japan Chemical Innovation Institute, 1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan, and JSR Corporation, Tsukuba Research Laboratory, Chiba Branch, Chigusa Kaigan 5, Ichihara, Chiba 299-0108, Japan
2. National Institute of Advanced Industrial Science and Technology (AIST), 1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
3. Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ohokayama, Meguro-ku, Tokyo 152-8552, Japan