Preparation of Polymeric Core-Shell and Multilayer Nanoparticles: Surface-Initiated Polymerization Using in Situ Synthesized Photoiniferters
Preparation of Polymeric Core-Shell and Multilayer Nanoparticles: Surface-Initiated Polymerization Using in Situ Synthesized Photoiniferters
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DOI：
10.1021/ma9019812
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发表时间：
2010-01-26
期刊：
影响因子：
5.5
通讯作者：
Mayes, Andrew G.
中科院分区：
文献类型：
--
作者：
Ali, A. M. Imroz;Mayes, Andrew G.
我们在这里报告了一种非常灵活的合成方法的开发，用于生成直径低于 100 nm 的核壳纳米粒子，从而在非水条件下在具有不同性能的各种有机溶剂中合成薄聚合物壳。这有利于在壳中掺入各种功能单体和交联剂，而无需对条件或方法进行重大改变。通过常规乳液聚合制备带有苄基氯官能团的聚合物核，然后用二乙基二硫代氨基甲酸钠衍生化以产生表面结合的引发-终止剂。光诱导的第二阶段表面引发聚合（SIP）导致壳的形成（通过动态光散射测量颗粒尺寸的增加），并且对尺寸分布进行了良好的控制。通过透射电子显微镜（TEM）成像和红外光谱法确认了所生成颗粒的核壳形态和壳层的组成。通过水性 Zeta 电位滴定研究验证了壳层中离子官能团的存在。通过利用表面引发的活性自由基机制，我们还依次合成了复杂的多层颗粒。即使在形成附加层之后，根据元素分析确定，大多数引发-终止剂基团也重新形成；因此，如果需要的话，进一步的颗粒细化是可能的。
We report here the development of a very flexible synthetic approach to generate core-shell nanoparticles below 100 nm diameter, whereby thin polymer shells are synthesized under nonaqueous conditions in a variety of organic solvents with diverse properties. This facilitates incorporation of a wide range of functional monomers and cross-linkers in the shell, without the need to make major changes to conditions or methodology. Polymer cores carrying benzyl chloride functionalities were prepared by conventional emulsion polymerization and then derivatized with sodium diethyldithiocarbamate to generate surface bound iniferters. Photoinduced second-stage surface-initiated polymerization (SIP) led to shell formation (measured as an increase in particle size by dynamic light scattering) with good control over the size distribution. The core-shell morphology of the particles generated was confirmed by transmission electron microscope (TEM) imaging and the composition of the shell layer with IR spectroscopy. The presence of ionic functionalities in the shell layer was verified by aqueous zeta potential titration studies. By exploiting the surface-initiated living radical mechanism, we have also synthesized complex multilayer particles sequentially. Even after the formation of an additional layer, the majority of the iniferter groups were re-formed as determined by elemental analysis; therefore, further particle elaboration would be possible if required.