Dynamics of Particle Migration Toward Interface and Tailored Directional Migration Strategy in Multiphase Melt Processing

ABSTRACT An intriguing physical phenomenon in multiphase melt processing—particle migration toward the interface between melts—enables the construction of lotus‐seed‐pod‐like micro/nano pits on polymer surfaces, offering a novel approach for large‐scale, low‐cost fabrication of flexible sensors. However, due to the black‐box nature of polymer processing, the underlying dynamics of particle migration remain unclear. Traditional techniques (e.g., scanning electron microscopy, laser confocal microscopy) only capture final particle distributions, challenging real‐time dynamics analysis. This study employs a Computational Fluid Dynamics‐Discrete Phase Model (CFD‐DPM) approach, solving interface evolution (Eulerian framework) and particle dynamics (Lagrangian framework), to elucidate the force‐velocity‐displacement‐aggregation relationship and the contribution of force components to particle migration. Combined with experiments, we clarify thermophoresis‐driven migration mechanisms and propose engineering strategies for directional control of particle migration. This work establishes a foundation for controlling particle migration, designing composite surface structures, and advancing flexible sensor manufacturing.