1. Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
2. Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, Korea
3. Seagate Technology, 47010 Kato Road, Fremont, California 94538, United States.