Sustainable Droplet Manipulation on Ultrafast Lubricant Self‐Mediating Photothermal Slippery Surfaces

Designing intelligent slippery surfaces for droplet manipulation is critical for many applications from drug delivery to bio‐analysis, while is of great challenging in sustainability for inescapable wastage of lubricant layer. Herein, an ultrafast lubricant self‐mediating (self‐replenishing/‐absorbing) photothermal slippery surface is designed that achieves sustainable transport of droplet under the irradiation of near infrared light (NIL) even if the lubricant layer is wiped clean completely, as well as at other man‐made extreme conditions. The ultrafast lubricant self‐mediating performance is caused by synergistic effects of interconnection of porous structure and photothermal expansion of the material. When lubricant on surface is lost, photothermal expansion of material can quickly squeeze the lubricant inside the base to flow into and out of the interconnected porous structure to generate a fresh lubricant layer. Attractively, when the NIL is turned off, the rebuilt lubricant layer can be swiftly self‐absorbed into the porous to inhibit unnecessary wastage. Moreover, an arbitrary split of droplet in desired configurations can be achieved by controlling the NIL irradiating route. This sustainable droplet manipulation induced by ultrafast lubricant self‐mediating can be extensively applied in microfluidics and micro‐reactor settings. A new design of lubricant self‐mediating photothermal slippery surface to achieve sustainable transport and arbitrary split of droplet under the irradiation of NIL even if the lubricant layer is wiped clean, as well as at other man‐made extreme conditions is proposed. This outstanding finding will extend the practical applications of droplet manipulation in microfluidic and biotechnological systems.