Drop/bubble transportation and controllable manipulation on patterned slippery lubricant infused surfaces with tunable wettability

Abstract

Directional transportation and manipulation of liquid droplets, which are of great significance for science and technologies, are mainly dependent on special surface wettability. Inspired by the carnivorous nepenthes, we fabricate a paraffin infused hybrid porous hydroxyapatite nanowires/carbon nanofibers film (PIHPHCF). The inorganic hydroxyapatite nanowires (HAPNWs) firmly intertwine with the carbon nanofibers (CNTs) to form a three-dimensional porous network after the self-assembly process. On account of the CNTs’ photothermal effect, the infused paraffin in PIHPHCF can transform from the solid state to a liquid state in response to near-infrared light irradiation (NIRLI, 808 nm), causing the wettability of the film to convert from hydrophobic to slippery. Through inducting variform mask layers, the slippery pathways melting from the lubricating paraffin are adjusted to different shapes such as ‘S’ and ‘Y’, where liquid droplets are able to be directionally transported. Additionally, potential application of the as-prepared patterned slippery film is explored as a microreactor and microfluidics device. Moreover, such a patterned slippery surface is successfully utilized to explore bubbles capture, manipulation and release under a warm-water environment. We anticipate that this work is poised to broaden the application of patterned slippery surfaces, as an example of which is liquid or bubble controllable transportation and manipulation.