利用RAFT聚合法合成含光致變性基團之雙性團聯狀高分子

Synthesis and Characterization of Diblock Copolymers Containing Photochromic Groups by RAFT Polymerization

黎正淵(Chung-Yuan Li)

指導教授 ： 楊博智

元智大學/工程學院/化學工程與材料科學學系/碩士(2012年)

摘要

本研究合成一系列具有不同間隙長度和末端基團之光致變性單體Nazo、Cazo、Nstil及Cstil系列，在分子結構設計上導入不同的拉電子基(硝基)或推電子基(甲烷氧基)，以及不同的分子核心azobenzene (N=N)基團或stilbene (C=C)衍生物，最後利用RAFT活性聚合技術與較親水性styrene和4-acetoxy styrene單體，聚合成雙性團聯狀高分子，探討其高分子分子結構與熱性質、光學性質的相關性及自組裝行為研究。本實驗合成的化合物以FT-IR、1H-NMR及EA 鑑定分子結構，以DSC 和TGA分析熱性質，並使用UV-Vis和PL光譜測量化合物之光學性質。在光學性質方面，利用一階光異構化動力學，計算出E-Z或Z-E 光化學異構化轉換程度及速率常數。RAFT活性聚合所合成的雙性團聯狀高分子利用GPC、FT-IR、1H-NMR、DSC、TGA和XRD分析性質，由GPC分析結果可知，poly(St-b-Cazo6)和poly(StO-b-Cazo6)重量平均分子量為8.82×103和11.48×103及PDI分別為1.48和1.26，相關雙性團聯狀高分子的自組裝效應和照射UV光前後的高分子表面形態，使用SEM、TEM和粒徑分析散射儀觀察其高分子表面型態及粒徑分佈情形。當水相增加時，親水端鏈段會將親油端鏈段包覆起來，形成微球狀，poly(St-b-Cazo6)在THF: H2O= 1: 9條件下，所形成的微相尺寸約220 nm，poly(StO-b-Cazo6)在THF: H2O= 9: 1條件下之平均粒徑為800 nm。

關鍵字

光致變性 ； 光異構化 ； 偶氮苯 ； 動力學 ； 自組裝

並列摘要

In this work, a series of azobenzene and stilbene-based photochromic monomers with six or eleven methylene segments as spacer, and with electron-donating (methoxy, OCH3) and electron-withdrawing (nitro, NO2) terminal groups were designed and synthesized. Two amphiphilic diblock copolymers, poly(St-b-Cazo6) and poly(StO-b-Cazo6) , were also synthesized with azobenzene monomer (Cazo6) using reverse addition-fragmentation transfer (RAFT) polymerization. Their structure-property effect, the effect on E/Z photoisomerization of molecular structures, and their self-assembled behaviors were also investigated. The synthesized photochromic compounds were characterized by FT-IR, 1H-NMR, EA, DSC, TGA, UV-V and PL spectra. The first-order photoisomerization kinetics that calculate E-Z or Z-E photoisomerization conversion degree and rate constants were evaluated. The synthesized diblock copolymers were also characterized by GPC, FT-IR, 1H-NMR, DSC, TGA and XRD. The weight-average molecular weights (Mw) of poly(St-b-Cazo6) and poly(StO-b-Cazo6) were 8.82×103 and 11.48×103 and their polydispersity index (PDI) were 1.48 and 1.26, respectively. The morphologies of self-assembled amphiphilic diblock copolymers before and after UV irradiation were analyzed using SEM, TEM, and laser particle size analyzer. With increasing the concentration of aqueous phase increased in THF solution, micelles would form that the hydrophilic “head” regions contact with the surrounding solvent. When the volume of THF/H2O was 1/9, the diameter of spherical micelles of poly(St-b-Cazo6) was 220 nm. However, when the volume of THF/H2O was 9/1, the diameter of spherical micelles of poly(StO-b-Cazo6) was 800 nm.

並列關鍵字

self-assembly ； photochromism ； photoisomerization ； azobenzene ； kinetics

參考文獻

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