Femtosecond-Laser-Ablated Porous Silver Nanowire Heater with Ultralow Driven-Voltage and Ultrafast Sensitivity for Highly Efficient Crude Oil Remedy.

The development of viscous-crude oil and water separation technology is important for overcoming pollution caused by oil spills. Although some separators responding to light, electric, and temperature have been proposed, their poor structural homogeneity and inferior controllability, together with weak capillary forces, hinder the rapid salvage of viscous crude oil. Herein, a Joule-heated hydrophobic porous oil/water separator is reported, which has advantages of low energy consumption (169.7 °C·cm·W), short thermal-response time (5 s) and rapid heating rate (13 °C/s). Under an ultralow voltage of 4.5 V, crude oil could infiltrate through the separator within 5 s. COMSOL simulation reveals the thermodynamics of crude oil's unidirectional collection. Significantly, the gradient wettability originating from the asymmetrical temperature on the dual face is the dominant driving force for efficient oil/water separation. Finally, a homemade device is successfully deployed for continuous viscous oil/water separation. This work provides a new avenue for viscous oil remedy.