Directional and Reconfigurable Assembly of Active Colloidal Motors Triggered by Chemical Communications

Abstract

AbstractAnisotropic colloidal particles can directionally self‐assemble, but the resulting assemblies cannot reconfigure unless the surface properties of colloidal particles change. Although external fields with adjustable inputs can guide the reconstruction of active structures after stimulating the dynamic assembly of active colloidal motors, the interaction between colloidal motors is unclear. Here, the study reports a bioinspired communication and directed assembly of peanut‐shaped colloidal motors with the emergence of ordered ribbon structures triggered by self‐generated chemical fields. The colloidal motors photocatalytically decompose the fuel to create the chemical concentration gradient fields and exert long‐range attractions on the colloidal scale, which enable colloidal motors to communicate by sensing each other, synchronizing orientation, and assembling side‐by‐side after the collision between their local flow fields. The inter‐individual communication occurs at a critical distance of ≈4.4 µm, resulting from the interplay between hydrodynamic effects, long‐ranged phoretic attraction, and short‐ranged magnetic interaction. The linear ribbons are still active owing to the symmetry breaking of the local fluid field and can be switched between rigid and flexible states according to light conditions to simulate the polymer conformation. The complexity of colloidal motors can be combined with external manipulations to manufacture active soft materials with precise and adaptive functions.