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dc.contributor.advisor정병문-
dc.contributor.author박수현-
dc.creator박수현-
dc.date.accessioned2016-08-26T12:08:26Z-
dc.date.available2016-08-26T12:08:26Z-
dc.date.issued2011-
dc.identifier.otherOAK-000000068007-
dc.identifier.urihttp://dspace.ewha.ac.kr/handle/2015.oak/189581-
dc.identifier.urihttp://dcollection.ewha.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000068007-
dc.description.abstract이 연구는 비슷한 조성을 갖고 있으나 블록 순서가 다른 폴리(에틸렌 글라이콜)-L-폴리알라닌-DL-폴리알라닌 (PEG-L-PA-DL-PA)과 폴리(에틸렌 글라이콜)-DL-폴리알라닌-L-폴리알라닌 (PEG-DL-PA-L-PA) 삼중블록 공중합체의 차이에 대하여 보고하고자 한다. 알파 나선의 L-폴리알라닌이 유연한 PEG와 DL-폴리알라닌 사이에 위치한 PEG-L-PA-DL-PA의 경우, 온도 증가에 따라 졸-젤 전이를 보였다. 반면, 점진적인 유연성을 갖는 PEG-DL-PA-L-PA는 온도 증가에 따라 졸-젤-스퀴즈된 젤 전이를 보였다. 낮은 온도에서 두 중합체 수용액의 L-폴리알라닌은 모두 알파 나선 이차 구조를 보였다. 온도 증가에 따라 PEG-L-PA-DL-PA에서는 이차 구조가 안정하게 유지되었지만, PEG-DL-PA-L-PA에서는 알파 나선에서 랜덤 코일로 변하였다. 저온-투과전자현미경으로 관찰한 결과, PEG-L-PA-DL-PA는 구형의 나노-회합을 보였고, PEG-DL-PA-L-PA는 구형 뿐만 아니라 짧은 실린더 모양의 나노-회합도 관찰할 수 있었다. 본 연구를 통해 블록 공중합체에서 조성은 같더라도 블록 순서가 달라짐에 따라 온도민감성과 나노-회합에 큰 차이가 생김을 알 수 있었다. 이러한 사실은 앞으로 새로운 생체재료를 디자인하는 데에 중요한 정보를 제공할 것 이다.;We are reporting triblock copolymers of (ethylene glycol)44-(L-alanine)9-(DL-alanine)9 (PEG-L-PA-DL-PA) with ??-helical L-PA localized between flexible PEG and DL-PA, and (ethylene glycol)44-(DL-alanine)9-(L-alanine)9 (PEG-DL-PA-L-PA) with gradient flexibility in water. Aqueous solutions of PEG-L-PA-DL-PA underwent only sol-to-gel transition, whereas those of PEG-DL-PA-L-PA underwent sol-to-gel-to-squeezed gel transitions as the temperature increased. The L-Pas of both polymers have an a-helical secondary structure in water as low temperature. However, the a-helical structure of the PEG-DL-PA-L-PA changed into a random coil structure as the temperature increased above 40 oC, whereas the PEG-L-PA-DL-PA kept the a-helical secondary structure over the same investigated temperature range of 4 oC to 50 oC. Cryo-transmission electron microscopy images and hynamic light scattering suggested that the PEG-L-PA-DL-PA develops spherical micelles, whereas the PEG-DL-PA-L-PA develops cylindrical bundles as well as spherical micelles in water. Even though both block copolymers have s similar composition of (ethylene glycol)44, (L-alanine)9, and (DL-alanine)9, they showed significantly different temperature-sensitivities as well as different nano-assemblies in water. This report suggests that the block sequence of a polymer is very important in developing a specific nano-structure as well as in controlling thermosensitivity of the polymer, thus providing useful molecular information in designing a biomaterial.-
dc.description.tableofcontentsCHAPTER 1 INTRODUCTION 1 1.1 Stimuli-sensitive polymers 2 1.2 Thermosensitive polymers 4 1.3 Hydrogel 9 1.3.1 Concept of hydrogel 9 1.3.2 In situ gelling hydrogel 15 1.4 PEG-based polymers 17 1.5 Peptide-based polymers 19 1.6 Parameters to control the gelation 21 1.7 Aims for this study 22 1.8 References 23 CHAPTER 2 The significance of block sequence in block copolymers to their thermosensitivity and nano-assembly 25 2.1 Introduction 26 2.2 Experimental section 28 2.2.1 Materials 28 2.2.2 Synthesis 28 2.2.3 Instruments and measurements 29 2.3 Results and discussion 33 2.3.1 Synthesis and characterization 33 2.3.2 Sol-to-gel transition study 37 2.3.3 Confirmation of sol-to-gel(-to-squeezed gel) transition: circular dichroism and 13C-NMR study 44 2.3.4 Self-assembly study 49 2.3.5 Schematic presentation of self-assembly 51 2.4 Conclusions 54 2.5 References 55 국문 요약 59-
dc.formatapplication/pdf-
dc.format.extent2168553 bytes-
dc.languageeng-
dc.publisher이화여자대학교 대학원-
dc.titleThe Significance of Block Sequence in Block Copolymers to Their Thermosensitivity and Nano-assembly-
dc.typeMaster's Thesis-
dc.title.translated블록 공중합체에서 블록 순서에 따른 온도민감성과 나노 회합-
dc.format.pageix, 60 p.-
dc.identifier.thesisdegreeMaster-
dc.identifier.major대학원 바이오융합과학과-
dc.date.awarded2011. 8-
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