Camacho Guillermo, de Vicente Juan
University of Granada, F2N2Lab, Magnetic Soft Matter Group, Department of Applied Physics, Faculty of Sciences, C/Fuentenueva s/n, 18071 Granada, Spain.
Phys Rev E. 2025 Apr;111(4-2):045414. doi: 10.1103/PhysRevE.111.045414.
Toggled field self-assembly is a useful way to circumvent kinetic arrest of the induced structures in field-directed self-assembly and, in particular, in magnetic suspensions such as magnetorheological (MR) fluids. During the field-off period, Brownian motion permits rearrangement of the particles and classical system-spanning chains (typically formed under uniaxial DC fields) collapse into dense ellipsoidal aggregates that are more energetically favorable. Here we show, through the use of experiments and particle-level simulations, that the process is very sensitive to the field configuration (e.g., frequency and strength), and, in particular, it can be dramatically accelerated when the magnetic field strength is increased. Moreover, when the field strength reaches sufficiently high values, the classical two-step aggregation process becomes a single one and morphological differences in the final structures emerge.
切换场自组装是一种有用的方法，可避免场诱导自组装中诱导结构的动力学停滞，特别是在磁悬浮体系中，如磁流变（MR）流体。在无场期间，布朗运动使颗粒重新排列，经典的跨越整个系统的链（通常在单轴直流场下形成）坍塌成能量上更有利的致密椭球状聚集体。在此，我们通过实验和颗粒级模拟表明，该过程对场配置（如频率和强度）非常敏感，特别是当磁场强度增加时，该过程可显著加速。此外，当场强达到足够高的值时，经典的两步聚集过程变为单步过程，最终结构出现形态差异。
