| 학회 | 한국고분자학회 |
| 학술대회 | 2004년 가을 (10/08 ~ 10/09, 경북대학교) |
| 권호 | 29권 2호, p.598 |
| 발표분야 | 기능성 고분자 |
| 제목 | pH-Induced Formation of Block-Selective Polypseudorotaxanes |
| 초록 | The inclusion complexation of cyclodextrins (CDs) with linear polymers is a topic of rapidly growing interest in the field of supramolecular self-assembly.1 In recent reports, a great deal of effort has been focused on the polypseudorotaxane formation between CDs and polymers with structural heterogeneity, such as random and block copolymers, since the properties of copolymer chains can be readily modulated, thereby resulting in the polypseudorotaxanes with numerous interesting properties, which have been impossible with the current homopolymer-based polypseudorotaxanes. In this study, we aim to study new pH-dependent polypseudorotaxane formation of α-CD with a linear ABA triblock copolymer consisting of polyethylenimine (PEI) and PEG (PEI-b-PEG-b-PEI). We are interested in knowing whether the threading/dethreading of α-CDs in the triblock copolymer of PEG and ionizable PEI is pH-controllable to induce block-selective inclusion complexation. α-CDs formed the polypseudorotaxane with PEI-b-PEG-b-PEI even at a pH below 8.0, whereas no complex formation was observed for a mixture of α-CDs and the PEI homopolymer. 1H NMR, X-ray diffraction, and 13C CP/MAS measurements verified that each block in the copolymer acted as guests for α-CDs at pH 11.0, whereas α-CDs on the PEI block were dethreaded exclusively to result in block-selective polypseudorotaxane formation based on the PEG middle block at pH below 8.0, where the secondary amines in the PEI block was protonated (pKa: 8.9).2 The threading/dethreading process of CDs along the PEI chains could be reversibly controlled by adjusting pH. Other interesting properties and significant observation will be presented. 참고문헌 1. K. M. Huh, H. Tomita, T. Ooya, W. K. Lee, S. Sasaki, N. Yui, Macromolecules, 35, 3775 (2002). 2. S. C. Lee, H. S. Choi, T. Ooya, and N. Yui, Macromolecules (in press). |
| 저자 | 이상천1, 김경자1, 최학수2, Tooru Ooya2, Nobuhiko Yui2 |
| 소속 | 1요업(세라믹)기술원 생체재료팀, 2Japan Advanced Institute of Science and Technology School of Materials Science |
| 키워드 | cyclodextrin; PEG; polyrotaxanes; stimuli-sensitive |
