Thermal gelation or gel melting: (ethylene glycol)113-(l-alanine)12 and (ethylene glycol)113-(l-lactic acid)12
- 주제(키워드) sol-gel transition , block copolymers , stimuli-sensi-tive polymers , self-assembly , micelles
- 등재 SCIE, SCOPUS
- 발행기관 John Wiley & Sons Inc.
- 발행년도 2014
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000097815
- 본문언어 영어
- Published As http://dx.doi.org/10.1002/pola.27254
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
When PEG (M.W.∼5000 Daltons) is conjugated to poly(l-alanine), the polymer aqueous solutions (<10.0 wt.%) undergo sol-to-gel (thermal gelation), whereas it is conjugated to poly(l-lactic acid), the polymer aqueous solutions (>30.0 wt.%) undergo gel-to-sol (gel melting) as the temperature increases. In the search for molecular origins of such a quite different phase behavior, poly(ethylene glycol)-poly(l-alanine) (PEG-PA; EG113-A12) and poly(ethylene glycol)-poly(l-lactic acid) (PEG-PLA; EG113-LA12) are synthesized and their aqueous solution behavior is investigated. PEG-PAs with an α-helical core assemble into micelles with a broad size distribution, and the dehydration of PEG drives the aggregation of the micelles, leading to thermal gelation, whereas increased molecular motion of the PLA core overwhelms the partial dehydration of PEG, thus gel melting of the PEG-PLA aqueous solutions occurs. The core-rigidity of micelles must be one of the key factors in determining whether a polymer aqueous solution undergoes sol-to-gel or gel-to-sol transition, as the temperature increases. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, , 52, 2434–2441
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