1. Department of Polymer Science and Engineering, Polymeric Nanomaterials Laboratory, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Deagu702-701, Korea
2. Hansol Chemical Co., Ltd., 873 Gwahak-ro, Bongdong-eup, Wanju-gun, Jeollabuk-do565-904, Korea