Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2012 May 2;134(17):7337-43. doi: 10.1021/ja209245v. Epub 2012 Apr 23.
We present the synthesis of nonspherical magnetic microparticles with multiple functionalities, shapes, and chemistries. Particle synthesis was performed in two steps: polymeric microparticles functionalized homogenously with carboxyl groups were generated using stop-flow lithography, and then in situ coprecipitation was used to grow magnetic nanoparticles at these carboxyl sites. With successive growth of magnetic nanoparticles, we obtained polymeric particles with saturation magnetizations of up to 42 emu/g microparticle. The growth in the magnetic nanoparticle mean size and polydispersity was determined from the magnetization curves obtained following each growth cycle; nanoparticle sizes were limited by the physical constraint of the effective mesh within the hosting gel microparticle. Particles with spatially segregated domains of varying magnetic properties (e.g., Janus particles, particles with step changes in magnetite concentration, etc.) can be synthesized readily using this approach.
我们提出了具有多种功能、形状和化学性质的非球形磁性微球的合成方法。颗粒合成分两步进行：首先使用停流光刻技术生成均匀功能化的带有羧基的聚合物微球，然后在这些羧基位点原位共沉淀生长磁性纳米颗粒。通过磁性纳米颗粒的连续生长，我们得到了饱和磁化强度高达 42 emu/g 微球的聚合物颗粒。通过对每个生长循环后获得的磁化曲线的分析，可以确定磁性纳米颗粒的平均尺寸和多分散性；纳米颗粒的尺寸受到宿主凝胶微球中有效网格的物理限制。使用这种方法可以很容易地合成具有不同磁性特性的空间分离域的颗粒（例如，具有不同磁性特性的 Janus 颗粒、具有磁铁矿浓度阶跃变化的颗粒等）。
