Citrus-peel-like durable slippery surfaces

We present a citrus-peel-like micro-cavity structure for the design of durable Slippery Liquid-Infused Porous Surfaces (SLIPSs). Owing to the re-entrant and enclosed nature of micro-cavity, lubricant oils can be stabilized by mitigating mass loss resulting from liquid displacement and shear drainage, respectively. Citrus-peel-like micro-cavity SLIPS displays two orders of magnitude enhancement in durability in the droplet-sliding test when compared with micro-pillar SLIPS and smooth lubricant surface. We demonstrated precise droplet manipulation without liquid loss and cross-contamination by harnessing the Marangoni effect with photo-thermal control. Cavity-smooth SLIPS with large adhesion contrast was patterned to initiate multiple droplet coalescences for on-demand neutralization reaction. The citrus-peel-like micro-cavity SLIPS would be beneficial to various applications, such as multi-step chemical reactions and bio-detections that require loss-free, contamination-free, and programmable droplet manipulation.