2025/05/27 by Galor Geva, Geva, Galor, Arin Escobar Ortiz +11 · 1 voice
Materials Science · Physics and Astronomy · #Force Microscopy Techniques and Applications #Micro and Nano Robotics #Pickering emulsions and particle stabilization
paper · doi:10.1103/2f4p-2xy7
openalex publication_date 2025/09/09 · openalex created_date 2025/11/15 · openalex updated_date 2026/06/11
Transport phenomena in complex and dynamic microscopic environments are fundamentally shaped by hydrodynamic interactions. In particular, microparticle transport in porous media is governed by the delicate interplay between particle-substrate friction and pressure forces. Here, we systematically investigate the motion of externally driven rotating magnetic microparticles near a substrate patterned with a square lattice of cylindrical obstacles, a model porous medium. Remarkably, we observe a reversal in the direction of particle translation as obstacle spacing decreases, highlighting a sensitive competition between shear-induced forward rolling and pressure-driven backward sliding due to flow-field symmetry breaking. These results demonstrate the crucial role of structured environments in determining microscale active particle transport, offering strategies for microfluidic design, targeted cargo delivery, and tunable active materials.