Gumieniczek-Chłopek Elżbieta, Odrobińska Joanna, Strączek Tomasz, Radziszewska Agnieszka, Zapotoczny Szczepan, Kapusta Czesław
Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza Av. 30, 30-059 Krakow, Poland.
Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
Materials (Basel). 2020 Mar 9;13(5):1219. doi: 10.3390/ma13051219.
This paper reports the characterization of iron oxide magnetic nanoparticles obtained via the thermal decomposition of an organometallic precursor, which were then loaded into nanocapsules prepared via the emulsification process in the presence of an amphiphilic derivative of chitosan. The applied synthetic method led to the formation of a hydrophobic layer on the surface of nanoparticles that enabled their loading in the hydrophobic liquid inside of the polymer-based capsules. The average diameter of nanoparticles was determined to be equal to 15 nm, and they were thoroughly characterized using X-ray diffraction (XRD), magnetometry, and Mössbauer spectroscopy. A core-shell structure consisting of a wüstite core and maghemite-like shell was revealed, resulting in an exchange bias effect and a considerable magnetocrystalline anisotropy at low temperatures and a superparamagnetic behavior at room temperature. Importantly, superparamagnetic behavior was observed for the aqueous dispersion of the nanocapsules loaded with the superparamagnetic nanoparticles, and the dispersion was shown to be very stable (at least 48 weeks). The results were analyzed and discussed with respect to the potential future applications of these nanoparticles and nanocapsules based on biopolymers as platforms designed for the magnetically navigated transport of encapsulated hydrophobic substances.
本文报道了通过有机金属前驱体热分解获得的氧化铁磁性纳米颗粒的表征，然后将其负载到在壳聚糖两亲衍生物存在下通过乳化过程制备的纳米胶囊中。所应用的合成方法导致在纳米颗粒表面形成疏水层，从而使其能够负载在基于聚合物的胶囊内部的疏水液体中。确定纳米颗粒的平均直径等于15nm，并使用X射线衍射（XRD）、磁强计和穆斯堡尔光谱对其进行了全面表征。揭示了由维氏体核和类磁赤铁矿壳组成的核壳结构，导致在低温下产生交换偏置效应和相当大的磁晶各向异性，以及在室温下呈现超顺磁性行为。重要的是，观察到负载超顺磁性纳米颗粒的纳米胶囊的水分散体具有超顺磁性行为，并且该分散体显示出非常稳定（至少48周）。针对这些基于生物聚合物的纳米颗粒和纳米胶囊作为设计用于磁性导航运输封装疏水物质的平台的潜在未来应用，对结果进行了分析和讨论。
