Predicting magnetic Janus particle assembly with differential evolution algorithm

Magnetic Janus particles allow access to complex, nonlinear assembled structures that may enable interesting new magnetorheological fluids with uniquely engineered field responses. However, the overwhelming size of the parameter space for Janus and patchy particles makes exploration of such systems by experimental trial and error or through detailed simulation impractical. Here, a differential evolution (DE)-based simulation method is explored to predict the assembly of magnetic Janus particles as an alternative method for assembly prediction. Structure predictions from the DE simulation for laterally and radially shifted magnetic Janus particles are compared to four published experimental and simulation case studies. The DE simulation captures the orientation and structure of magnetic Janus particles for a range of shifts and a variety of external field conditions using the point dipole approximation. Structural predictions that rely on the reorganization of large clusters of particles were less well represented by the DE predictions. Despite this limitation, the DE simulation method can be used to predict key structural factors for magnetic Janus particle assemblies, as demonstrated by favorable comparison with three of the four model studies.