Synthesis of Cylindrical Polymer Brushes with Umbrella-Like Side Chains via a Combination of Grafting-from and Grafting-onto Methods

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• 作者：Yi Shi ; Wen Zhu ; Yongming Chen
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：March 26, 2013
• 年：2013
• 卷：46
• 期：6
• 页码：2391-2398
• 全文大小：474K
• 年卷期：v.46,no.6(March 26, 2013)
• ISSN：1520-5835

文摘

Cylindrical polymer brushes with umbrella-like side chains have been synthesized by a combination of grafting-from and grafting-onto methods. First, the polymer brushes with azido end-functionalized poly(tert-butyl acrylate) (PtBA-N₃) side chains, PBIEM-g-(PtBA-N₃), were prepared by atom transfer radical polymerization (ATRP) of tBA monomers using polyinitiator PBIEM followed by a substitution of bromo-side terminals with sodium azide. Subsequently, polyamidoamino dendrons of three generations with a propargyl focal point (Gn) were introduced onto the brush-shaped PtBA-N₃ by copper-catalyzed azide鈥揳lkyne cycloaddition (CuAAC) coupling reaction. The efficiency of CuAAC between PtBA-N₃ side chains and Gn has showed a dependence on generation number n of the dendrons. At the feed ratio of [Gn]:[N₃] = 1:1, the grafting efficiency of the first generation dendron (G1) reached above 95%, whereas that of G2 and G3 was at least 84% and 73%, respectively. AFM images indicated that diameter of the brushes hybridized with G3 increased obviously than that of the brushes without dendrons.