Control of Dispersity and Grafting Density of Particle Brushes by Variation of ATRP Catalyst Concentration
Control of Dispersity and Grafting Density of Particle Brushes by Variation of ATRP Catalyst Concentration
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DOI：
10.1021/acsmacrolett.9b00405
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发表时间：
2019-07-01
影响因子：
7.015
通讯作者：
Matyjaszewski, Krzysztof
中科院分区：
文献类型：
--
作者：
Wang, Zongyu;Yan, Jiajun;Matyjaszewski, Krzysztof
通过电子转移活化剂再生（ARGET）原子转移自由基聚合（ATRP）制备了带有接枝聚甲基丙烯酸甲酯刷的二氧化硅颗粒SiO2-g-PMMA。聚合物刷的接枝密度和分散性通过初始ATRP催化剂浓度（[Cu-II/L]（0））来调节。在非常低的催化剂浓度（[Cu-II/L]（0）< 1 ppm）下获得稀疏接枝的颗粒刷，其在TEM图像中也显示出各向异性的线状结构。初始催化剂浓度对粒子刷系统中分散性和引发效率的影响与线性PMMA均聚物合成中观察到的相似。动力学研究表明，从受控的自由基聚合的过渡到一个控制较少的过程中，在低单体转化率，当[Cu-II/L]（0）下降到约10 ppm以下。
Silica particles with grafted poly(methyl methacrylate) brushes, SiO2-g-PMMA, were prepared via activator regeneration by electron transfer (ARGET) atom transfer radical polymerization (ATRP). The grafting density and dispersity of the polymer brushes was tuned by the initial ATRP catalyst concentration ([Cu-II/L](0)). Sparsely grafted particle brushes, which also displayed an anisotropic string-like structure in TEM images, were obtained at very low catalyst concentrations, [Cu-II/L](0) < 1 ppm. The effect of the initial catalyst concentration on dispersity and initiation efficiency in the particle brush system was similar to that observed in the synthesis of linear PMMA homopolymers. The kinetic study revealed a transition from controlled radical polymerization to a less controlled process at low monomer conversion, when the [Cu-II/L](0) decreased below about 10 ppm.