A fuel-free polymer-based micropump with optically tunable pumping directions

Micropumps, especially those based on polymers, have shown great potential in sensing and mass transportation applications. However, polymer-based micropumps only exhibit a certain pumping direction, which is not adjustable, thus limiting their further applications. In this paper, a light-driven micropump with tunable pumping directions is reported. The direction control of this micropump relies on the photothermal effect of the polymeric component and the light-induced release of the encapsulated surfactant. Both on–off, inward and outward, or even the unique heartbeat-like pumping behaviors could be realized. The direction-controlled micropump has great potential for a variety of applications. Among others, it has the ability to rectify the fluid flow or accelerate the solution stirring.