Silicone Oil‐Infused Polydimethylsiloxane Surfaces with Reduced Interface Hysteresis for Enhanced Oil‐Water Separation

A simple yet effective strategy is presented to create silicone oil‐infused polydimethylsiloxane (PDMS) surfaces with reduced interface hysteresis for efficient oil–water separation. The modified surfaces maintain hydrophobicity while significantly enhancing oleophilicity and reducing sliding angles for both liquids. Infused PDMS sponges demonstrate five‐fold faster oil absorption compared to untreated controls, with performance enhancement attributed primarily to reduced interface hysteresis rather than oil viscosity. When applied as coatings on metal meshes, these surfaces enable continuous separation with oil selectively penetrating through while water remains above. Microfluidic experiments confirm accelerated liquid transport in treated channels under identical pressure conditions. Moreover, these surfaces exhibit self‐healing properties, recovering their original lubricity within 24 h after water immersion. This work provides new insights into the role of interface hysteresis in oil–water separation and introduces a reliable approach to address this critical challenge, offering an effective solution for oil spill remediation and selective liquid transport applications.