Anderson Nicholas R, Davidson Jonathon, Louie Dana R, Serantes David, Livesey Karen L
UCCS Biofrontiers Center, University of Colorado at Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918, USA.
Instituto de Investigacións Tecnolóxicas and Applied Physics Department, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Nanomaterials (Basel). 2021 Oct 27;11(11):2870. doi: 10.3390/nano11112870.
The agglomeration of ferromagnetic nanoparticles in a fluid is studied using nanoparticle-level Langevin dynamics simulations. The simulations have interdigitation and bridging between ligand coatings included using a computationally-cheap, phenomenological sticking parameter . The interactions between ligand coatings are shown in this preliminary study to be important in determining the shapes of agglomerates that form. A critical size for the sticking parameter is estimated analytically and via the simulations and indicates where particle agglomerates transition from well-ordered ( is small) to disordered ( is large) shapes. Results are also presented for the hysteresis loops (magnetization versus applied field) for these particle systems in an oscillating magnetic field appropriate for hyperthermia applications. The results show that the clumping of particles has a significant effect on their macroscopic properties, with important consequences on applications. In particular, the work done by an oscillating field on the system has a nonmonotonic dependence on .
利用纳米颗粒级的朗之万动力学模拟研究了流体中铁磁性纳米颗粒的团聚现象。模拟中包括了配体涂层之间的交叉指状结构和桥接结构，采用了一种计算成本较低的唯象粘附参数。在这项初步研究中表明，配体涂层之间的相互作用对于确定形成的团聚体形状很重要。通过解析和模拟估计了粘附参数的临界尺寸，该尺寸表明颗粒团聚体从有序（粘附参数小）到无序（粘附参数大）形状的转变位置。还给出了这些颗粒系统在适用于热疗应用的振荡磁场中的磁滞回线（磁化强度与外加磁场）结果。结果表明，颗粒的团聚对其宏观性质有显著影响，对应用有重要影响。特别是，振荡场对系统所做的功对粘附参数具有非单调依赖性。
