Droplet Manipulation on Lubricant Self-Mediating Slippery PDMS Films.

Further exploration is needed for sustainable and precise droplet manipulation on intelligent surfaces, especially the problem of SLIPS failure caused by lubricant loss. In this work, a self-mediating photothermal lubrication surface was designed. Through a simple preparation method, it was possible to generate a new lubrication layer through near-infrared light (NIL) and perform sustainable and precise droplet manipulation even after the surface lubricant was consumed. The thermal expansion film obtained from polydimethylsiloxane (PDMS) and nano ferric oxide, combined with the connected structure obtained through laser etching technology, effectively preserve lubricating oil. After the surface lubricating oil is consumed, under the action of NIL, the lubricating oil inside the film is squeezed out, forming a new lubricating layer. At the same time, programmable droplet transport can be achieved by inducing the direction of NIL. After turning off NIL, the lubricating oil is absorbed into the network structure, achieving good circulation. This not only reduces the loss of lubricating oil, but also facilitates the manipulation of droplets. In addition, the movement (plane and antigravity) and splitting behavior of droplets are also discussed. This sustainable and precise manipulation of liquid droplets on the LSSPF (lubricant self-mediating slippery PDMS films) surface can be widely applied in various micro reaction devices.