Schmidtke Christian, Eggers Robin, Zierold Robert, Feld Artur, Kloust Hauke, Wolter Christopher, Ostermann Johannes, Merkl Jan-Philip, Schotten Theo, Nielsch Kornelius, Weller Horst
Institute of Physical Chemistry, University of Hamburg , Grindelallee 117, 20146 Hamburg, Germany.
Langmuir. 2014 Sep 23;30(37):11190-6. doi: 10.1021/la5021934. Epub 2014 Sep 10.
The combination of superstructure-forming amphiphilic block copolymers and superparamagnetic iron oxide nanoparticles produces new nano/microcomposites with unique size-dependent properties. Herein, we demonstrate the controlled clustering of superparamagnetic iron oxide nanoparticles (SPIOs) ranging from discretely encapsulated SPIOs to giant clusters, containing hundreds or even more particles, using an amphiphilic polyisoprene-block-poly(ethylene glycol) diblock copolymer. Within these clusters, the SPIOs interact with each other and show new collective properties, neither obtainable with singly encapsulated nor with the bulk material. We observed cluster-size-dependent magnetic properties, influencing the blocking temperature, the magnetoviscosity of the liquid suspension, and the r2 relaxivity for magnetic iron oxide nanoparticles. The clustering methodology can be expanded also to other nanoparticle materials [CdSe/CdS/ZnS core/shell/shell quantum dots (QDs), CdSe/CdS quantum dots/quantum rods (QDQRs), gold nanoparticles, and mixtures thereof].
形成超结构的两亲性嵌段共聚物与超顺磁性氧化铁纳米颗粒相结合，产生了具有独特尺寸依赖性性质的新型纳米/微复合材料。在此，我们展示了使用两亲性聚异戊二烯-嵌段-聚（乙二醇）二嵌段共聚物，将超顺磁性氧化铁纳米颗粒（SPIOs）从离散封装的SPIOs控制聚集成包含数百个甚至更多颗粒的巨型团簇。在这些团簇中，SPIOs相互作用并展现出新的集体性质，这在单封装的SPIOs或块状材料中均无法获得。我们观察到了团簇尺寸依赖性的磁性质，其影响了阻塞温度、液体悬浮液的磁黏滞性以及磁性氧化铁纳米颗粒的r2弛豫率。这种聚集方法也可以扩展到其他纳米颗粒材料[CdSe/CdS/ZnS核/壳/壳量子点（QDs）、CdSe/CdS量子点/量子棒（QDQRs）、金纳米颗粒及其混合物]。
