Light-Activated Active Colloid Ribbons.

Lin, Zhihua; Si, Tieyan; Wu, Zhiguang; Gao, Changyong; Lin, Xiankun; He, Qiang

We report a dynamic self-organization of self-propelled peanut-shaped hematite motors from non-equilibrium driving forces where the propulsion can be triggered by blue light. They result in one-dimensional, active colloid ribbons with a positive phototactic characteristic. The motion of colloid motors is ascribed to the diffusion-osmotic flow in a chemical gradient by the photocatalytic decomposition of hydrogen peroxide fuel. We show that self-propelled peanut-shaped colloids readily form one-dimensional, slithering ribbon structures under the out-of-equilibrium collisions. This self-organization intrinsically results from the competition among the osmotically driven motion, the phoretic attraction and the inherent magnetic moments. The giant size number fluctuation in colloid ribbons is observed above a critical point 4.1 % of the surface density of colloid motors. Such phototactic colloid ribbons may provide a model system to understand the emergence of function in biological systems and have potential to construct bioinspired active materials based on different active building blocks.

COLLOIDS; HEMATITE; RIBBONS; HYDROGEN peroxide; CHEMICAL equilibrium; CRITICAL point (Thermodynamics)

Angewandte Chemie, 2017, Vol 129, Issue 43, p13702

0044-8249

Academic Journal

10.1002/ange.201708155