Experimental study on the self-diffusiophoresis of the Janus micromotor in complex fluids

Janus micro/nanomotors have shown broad application prospects as drug delivery tools in biomedicine or energy generators for micro/nano-robots working under complex conditions. Existing studies have focused on the self-diffusiophoresis of Janus micro/nanomotors in simple liquids such as water, however, the research on the mechanism and characteristics of the self-diffusiophoresis in complex fluids is still lacking. This work experimentally investigates the self-diffusiophoresis of 2.06 μm Janus micromotors in polymer PEO solutions. The results systematically describe the influence of the PEO concentration on the propulsion speed of the Janus micromotor, the mean square displacements of the motion, and the rotation feature. Our findings show that the PEO polymers not only influence the viscosity of the solution, but also cause sub-diffusive and super-diffusive behaviors in the short-time and intermediate-time propulsion regime respectively, and result in an anomalous enhancement of the rotation of the Janus micromotors.