Highly temperature responsive core-shell magnetic particles: Synthesis, characterization and colloidal properties
Highly temperature responsive core-shell magnetic particles: Synthesis, characterization and colloidal properties
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DOI：
10.1016/j.jcis.2011.04.078
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发表时间：
2011-08-15
影响因子：
9.9
通讯作者：
Elaissari, Abdelhamid
中科院分区：
文献类型：
--
作者：
Rahman, Md Mahbubor;Chehimi, Mohamed M.;Elaissari, Abdelhamid
采用两步种子乳液聚合工艺制备了温敏磁性聚合物亚微米粒子。首先，以过硫酸钾（KPS）为引发剂，二乙烯基苯（DVB）为交联剂，在水包油磁性乳液（有机磁流体液滴）存在下，通过苯乙烯的乳液聚合得到磁性种子聚合物颗粒。之后，DVB交联的磁性聚合物颗粒被用作N-异丙基丙烯酰胺（NIPAM）的沉淀聚合中的种子，以在交联的磁性聚合物颗粒的疏水聚合物表面上诱导热敏PNIPAM壳。以N，N '-亚甲基双丙烯酰胺（MBA）和偶氮二（2-甲基丙脒）二盐酸盐（V-50）为引发剂，甲基丙烯酸氨乙酯盐酸盐（AEMH）为功能单体，NIPAM为交联剂，PNIPAM为温敏性聚合物。研究了晶种与单体（w/w）比沿着以及晶种性质对最终颗粒形态的影响。动态光散射（DLS）结果表明，颗粒在低于体积相变温度（VPTT）时溶胀，在高于VPTT时去溶胀。通过透射电子显微镜（TEM）证实了所制备的粒子具有完美的核（磁）壳（聚合物）结构。通过热重分析（TGA）确定颗粒的化学组成。研究了温度、pH值、离子强度等因素对微米级热敏磁性微粒的粒径、Zeta电位等胶体性质的影响。此外，还对磁性高分子核壳结构的形成机理进行了探讨。(C)2011 Elsevier Inc. All rights reserved.
Temperature responsive magnetic polymer submicron particles were prepared by two step seed emulsion polymerization process. First, magnetic seed polymer particles were obtained by emulsion polymerization of styrene using potassium persulfate (KPS) as an initiator and divinylbenzne (DVB) as a cross-linker in the presence of oil-in-water magnetic emulsion (organic ferrofluid droplets). Thereafter, DVB cross-linked magnetic polymer particles were used as seed in the precipitation polymerization of N-isopropylacrylamide (NIPAM) to induce thermosensitive PNIPAM shell onto the hydrophobic polymer surface of the cross-linked magnetic polymer particles. To impart cationic functional groups in the thermosensitive PNIPAM backbone, the functional monomer aminoethylmethacrylate hydrochloride (AEMH) was used to polymerize with NIPAM while N,N'-methylenebisacrylamide (MBA) and 2, 2'-azobis (2-methylpropionamidine) dihydrochloride (V-50) were used as a cross-linker and as an initiator respectively. The effect of seed to monomer (w/w) ratio along with seed nature on the final particle morphology was investigated. Dynamic light scattering (DLS) results demonstrated particles swelling at below volume phase transition temperature (VPTT) and deswelling above the VPTT. The perfect core (magnetic) shell (polymer) structure of the particles prepared was confirmed by Transmission Electron Microscopy (TEM). The chemical composition of the particles were determined by thermogravimetric analysis (TGA). The effect of temperature, pH, ionic strength on the colloidal properties such as size and zeta potential of the micron sized thermo-sensitive magnetic particles were also studied. In addition, a short mechanistic discussion on the formation of core-shell morphology of magnetic polymer particles has also been discussed. (C) 2011 Elsevier Inc. All rights reserved.