The Polymer Society of Korea

Abstract

We present heterogeneous oil-infused porous surfaces (HOIPSs) for programmable and precise directional control of water droplets. By selectively infusing two immiscible lubricants into chemically patterned nanopores, HOIPSs create surface hydrophobic gradients that repel droplets toward less hydrophobic regions, enabling uphill transport by balancing gravity and interfacial forces. The system allows tunable droplet motion by varying lubricant viscosity, tilt angle, and track geometry. This design can be extended to function as a mass-recognizing, logic-gated droplet router, enabling selective control based on droplet size or weight. HOIPSs further support controlled droplet merging, splitting, and guided movement, even on flexible or curved substrates. This approach offers a robust and scalable platform for programmable liquid manipulation, with potential applications in water harvesting and microfluidics.