Fu Rong, Yan Yuying, Roberts Clive, Liu Zeyu, Chen Yiyi
Centre for Fluids & Thermal Engineering Research, University of Nottingham Ningbo China, Ningbo, 315100, China.
Fluids & Thermal Engineering Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK.
Sci Rep. 2018 Mar 16;8(1):4704. doi: 10.1038/s41598-018-23225-5.
This work aims to investigate the influence of inter-particle dipole interactions on hyperthermia heating colloidal clusters of densely-packed FeO nanoparticles at low field intensity. Emulsion droplet solvent evaporation method was used to assemble oleic acid modified FeO particles into compact clusters which were stabilized by surfactant in water. Both experimental and simulation works were conducted to study their heating performance at different cluster's sizes. The dipole interactions improve the heating only when the clusters are small enough to bring an enhancement in clusters' shape anisotropy. The shape anisotropy is reduced at greater clusters' sizes, since the shapes of the clusters become more and more spherical. Consequently, the dipole interactions change to impair the heating efficiency at larger sizes. When the clusters are totally isotropic in shape, the heating efficiency is lower than that of non-interacting particles despite the cluster's size, although the efficiency increases by a little bit at a particular size most likely due to the dipole couplings. In these situations, one has to use particles with higher magnetic anisotropy and/or saturation magnetization to improve the heating.
这项工作旨在研究粒子间偶极相互作用对低场强下紧密堆积的FeO纳米颗粒热疗加热胶体团簇的影响。采用乳液滴溶剂蒸发法将油酸改性的FeO颗粒组装成紧密团簇，这些团簇在水中由表面活性剂稳定。通过实验和模拟研究了不同团簇尺寸下它们的加热性能。只有当团簇足够小以增强团簇形状各向异性时，偶极相互作用才会改善加热效果。在更大的团簇尺寸下，形状各向异性降低，因为团簇形状变得越来越接近球形。因此，在更大尺寸下，偶极相互作用会降低加热效率。当团簇形状完全各向同性时，尽管团簇尺寸不同，但其加热效率低于非相互作用颗粒，不过在特定尺寸下效率会略有增加，这很可能是由于偶极耦合。在这些情况下，必须使用具有更高磁各向异性和/或饱和磁化强度的颗粒来改善加热效果。
