Self-assembly of spherical colloidal particles with off-centered magnetic dipoles
Self-assembly of spherical colloidal particles with off-centered magnetic dipoles
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DOI：
10.1039/c3sm27128e
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发表时间：
2013-01-01
期刊：
影响因子：
3.4
通讯作者：
Linse, Per
中科院分区：
文献类型：
--
作者：
Abrikosov, Alexei I.;Sacanna, Stefano;Linse, Per
通过蒙特卡罗模拟研究了具有偏心嵌入磁偶极子的球形胶体流体。考虑了在不施加和施加外部磁场的情况下限制在二维空间中的具有不同强度和嵌入偶极矩方向的胶体系统。流体通过径向分布函数、角分布函数、聚类数据和能量数据来表征。在没有外场的情况下，胶体在足够大的磁矩下形成二聚体和三聚体，而没有形成胶体链的趋势，如在具有中心磁偶极子的颗粒的系统中出现的那样。在存在外场的情况下，对于平行于颗粒平面的场，形成以之字形排列的胶体链，而在存在垂直于该平面的场的情况下，胶体排序受到抑制。这些发现与最近对含有嵌入单畴磁性赤铁矿立方体的球形聚合物胶体的流体的实验观察结果惊人地一致（S. Sacanna, L. Rossi, and D. J. Pine, J. Am. Chem. Soc., 2012, 134, 6112）。
Fluids of spherical colloids possessing an off-centered embedded magnetic dipole were investigated by using Monte Carlo simulations. Systems of colloids with different strengths and directions of the embedded dipole moment confined in a 2D space without and with an external magnetic field applied were considered. The fluids were characterized by radial distribution functions, angular distribution functions, cluster data, and energetic data. In the absence of an external field, the colloids form dimers and trimers at sufficiently large magnetic moment without the tendency of forming chains of colloids as appearing in systems with particles possessing a central magnetic dipole. In the presence of an external field, chains of colloids aligned in a zigzag fashion were formed for a field parallel to the plane of the particles, whereas the colloidal ordering was suppressed in the presence of a field perpendicular to that plane. The findings agree surprisingly well with the recent experimental observations on fluids containing spherical polymer colloids with embedded single-domain magnetic hematite cubes (S. Sacanna, L. Rossi, and D. J. Pine, J. Am. Chem. Soc., 2012, 134, 6112).