1. Nano Materials R&D, Thermolon Korea, Ltd., 16th Floor, Cangen Tower, 6-ga 12, Jungang-dong, Jung-gu, Busan 614-714, Korea, Department of Polymer Science and Engineering, Pusan National University, 30 Jangjeon-dong Geumjeong-gu, Busan 609-735, Korea, and Materials Science and Engineering Department, University of Florida, P.O. Box 116400, Gainesville, Florida 32611