Reconfigurable superstructures of photocatalytic colloidal motors under light, magnetic, and acoustic fields

Abstract

We report on the dynamic self-assembly of TiO₂–Fe photocatalytic colloidal motors into reconfigurable superstructures when subjected to UV illumination, magnetic fields, and acoustic confinement. Tuning the light intensity and magnetic field strength enables in situ control over cluster size, rotation speed, and structural compactness. Four distinct phases emerge from the interplay of dipolar repulsion, self-propulsion, and phoretic attraction. Our work presents a generalizable strategy for programmable active matter and microrobotic swarms adapting to a complex and changing environment.