Isojima Tatsushi, Lattuada Marco, Vander Sande John B, Hatton T Alan
Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
ACS Nano. 2008 Sep 23;2(9):1799-806. doi: 10.1021/nn800089z.
Janus nanoparticles have been synthesized consisting of approximately 5 nm magnetite nanoparticles coated on one side with a pH-dependent and temperature-independent polymer (poly(acrylic acid), PAA), and functionalized on the other side by a second (tail) polymer that is either a pH-independent polymer (polystyrene sodium sulfonate, PSSNa) or a temperature-dependent polymer (poly(N-isopropyl acrylamide), PNIPAM). These Janus nanoparticles are dispersed stably as individual particles at high pH values and low temperatures, but can self-assemble at low pH values (PSSNa) or at high temperatures (>31 degrees C) (PNIPAM) to form stable dispersions of clusters of approximately 80-100 nm in hydrodynamic diameter. The Janus nanoparticle compositions were verified using FTIR and XPS, and their structures observed directly by TEM. Their clustering behavior is analyzed by dynamic light scattering and zeta potential measurements.
已经合成了双面纳米颗粒，其由大约5纳米的磁铁矿纳米颗粒组成，该磁铁矿纳米颗粒的一侧涂覆有pH依赖性且温度不依赖性的聚合物（聚丙烯酸，PAA），另一侧通过第二种（尾部）聚合物功能化，该聚合物要么是pH不依赖性聚合物（聚苯乙烯磺酸钠，PSSNa），要么是温度依赖性聚合物（聚N-异丙基丙烯酰胺，PNIPAM）。这些双面纳米颗粒在高pH值和低温下作为单个颗粒稳定分散，但在低pH值（PSSNa）或高温（>31摄氏度）（PNIPAM）下可以自组装形成流体动力学直径约为80-100纳米的簇的稳定分散体。使用傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）验证了双面纳米颗粒的组成，并通过透射电子显微镜（TEM）直接观察其结构。通过动态光散射和zeta电位测量分析了它们的聚集行为。
