1. Department
of Materials Science and Engineering, Hongik University 72-1, Sangsu-dong,
Mapo-gu, Seoul 121-791, Korea
2. Korea Basic Science Institute, Jukheon-gil, Gangneung 210-702, Gangwon-do, Korea
3. HMC&Green Research Institute, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Korea
4. School of
Polymer Science and Engineering, Chonnam National University, Gwangju 61186, Korea