Synthesis and Characterization of Well-Defined DEH-PPV-b-PEO Amphiphilic Rod-Coil Block Copolymers via "Click Reaction"
|關鍵字:||聚(對亞苯基-亞乙烯基);聚氧化乙烯;速配接合反應;微胞;微觀相分離;層狀結構;DEH-PPV;PEO;1,3-dipolar cycloaddition reaction;microphase separate;lamellae;micelle||公開日期:||2007||摘要:||本研究之目標為合成出具有自我組裝成規則形態(morphology)之雙嵌段式共聚物(diblock copolymer)，並探討其性質。本研究利用Siegrist polycondensation合成並酸化得到兩組單一尾端具醛基(aldehyde)官能基之可溶性導電高分子，聚對亞苯基-亞乙烯基(Poly(2,5-di(2’-ethylhexyloxy)-1-4-phenylenevinylene), DEH-PPV)，其分子量各為5.5K及3.4K，且成功將尾端醛基改質成碳-碳三鍵(alkyne)官能基，並與三組不同分子量尾端改質成疊氮化物(azide)之聚氧化乙烯(Poly(ethylene glycol) methyl ether, PEO)交叉配對組合，利用碳-碳三鍵官能基與疊氮官能基進行速配接合反應(click reaction)，合成出六組含PEO體積分率(
The self-assembly of block copolymers into nanostructure with novel morphology and property has attracted an increasing interest as a new approach for nanotechnology. In particular, block copolymers containing conducting polymer segments such as poly (phenylene vinylene) (PPV) are technologically important since PPVs are promising material for applications in low cost, large area and flexible organic optoelectronics. In this thesis, I described a novel method to synthesize poly(2,5-di(2’-ethylhexyloxy)-1-4-phenylenevinylene)-b-poly(ethylene oxide) (DEH-PPV-b-PEO) block copolymers via a coupling reaction of end-functionalized polymer building blocks such as 1,3-dipolar cycloaddition reaction between an alkyne terminated DEH-PPV and an azide terminated PEO. Aldehyde terminated monodispersed DEH-PPV homopolymers were synthesized using Siegrist polycondensation of 2,5-di(2”-ethylhexyloxy)-4’-methyl-N-benzylideneaniline and subsequently substitution of the terminal imino group with acid. Alkyne terminated PPV was obtained by reaction of aldehyde terminated PPV with propargyl bromide. Azide terminated PEO were synthesized by tosylation of the hydroxyl functionality of poly(ethylene glycol) methyl ether and subsequent substitution with sodium azide. The synthesized PPV-b-PEO block copolymers were characterized by various techniques including GPC, NMR, DSC, TGA, solution UV-Vis and PL. The microstructure and domain spacing for the synthesized block copolymers were further examined using small-angle x-ray scattering technique (SAXS). These block copolymers microphase separate and self-assemble into nanostructures of lamellae irrespective to the different PEO fractions, indicating the rod nature of PPV block. PPV-b-PEO shows significant solvatochromic transformation in different solvent/non-solvent mixture. The optical property of the PPV-b-PEO solution can be explained on the basis of aggregation, agglomeration, and collapse of isolated chains of PPV as well as the micelle and inverse micelle structures of PPV-b-PEO. The synthesis of PPV-b-PEO opens up the opportunity to study amphiphilic rod-coil block copolymers for future application.
在 IR 系統中的文件，除了特別指名其著作權條款之外，均受到著作權保護，並且保留所有的權利。