Bauman Moscow State Technical University, 2nd Baumanskaya Str. 5, 105005 Moscow, Russia.
J Chem Phys. 2019 Dec 28;151(24):244103. doi: 10.1063/1.5131255.
Tunable interactions in colloids, induced by rotating electric or magnetic fields, provide a flexible and promising tool for self-assembly of soft materials, as well as for fundamental particle-resolved studies of phase transitions and other generic phenomena in condensed matter. In the case of two-dimensional systems and the in-plane rotating fields, the interactions are known to have a long-range (dipolar) attraction and an expressed three-body part at short distances, but still remain poorly understood. Here, we show that the interactions and polarization mechanisms governing the tunable interactions can be described, calculated, and analyzed in detail with the diagrammatic method we proposed. The diagrams yield a clear illustration of different polarization processes contributing to the Keesom, Debye, London, self, and external energies, classified in colloids similarly to intermolecular interactions. The real tunable interactions, obtained with the boundary element method, can be simply and accurately interpolated with the set of basis of the diagrams attributed to different physically clear polarization processes. Calculation of large-distance behavior and interpolation of the many-body interactions (and analysis of the leading mechanisms contributing to them) excellently illustrate that the diagrammatic method provides deep insights into the nature of tunable interactions. The method can be generalized for multicomponent systems, suspensions of particles with a composite structure and a complicated shape. The results provide significant advance in theoretical methods for detailed analysis of tunable interactions in colloids and, therefore, the method is of broad interest in condensed matter, chemical physics, physical chemistry, materials science, and soft matter.
胶体中的可调相互作用，通过旋转电场或磁场诱导产生，为软物质的自组装以及凝聚态物质中相转变和其他通用现象的基本粒子分辨研究提供了灵活而有前途的工具。在二维系统和平面内旋转场的情况下，已知相互作用具有长程（偶极）吸引力和短程的明显三体部分，但仍然了解甚少。在这里，我们表明，可以用我们提出的图论方法详细描述、计算和分析控制可调相互作用的相互作用和极化机制。这些图清楚地说明了不同的极化过程对 Keesom、Debye、London、自和外部能量的贡献，这些能量在胶体中类似于分子间相互作用进行分类。通过边界元方法获得的真实可调相互作用可以简单而准确地用与不同物理清晰极化过程相关的图基的集合进行插值。大距离行为的计算和多体相互作用的插值（以及对其起主要作用的机制的分析）很好地说明了图论方法为可调相互作用的本质提供了深入的见解。该方法可推广到多组分系统、具有复合结构和复杂形状的颗粒悬浮液中。该结果为胶体中可调相互作用的详细分析提供了理论方法的重大进展，因此，该方法在凝聚态物质、物理化学、物理化学、材料科学和软物质等领域具有广泛的兴趣。
