Engineered photothermal Janus systems for controllable unidirectional crude oil manipulation in marine spill recovery

Efficient and rapid cleanup of offshore oil spills remains a significant global challenge, primarily due to the high viscosity and low fluidity of most crude oils. Herein, a functional engineered Janus copper foam, integrating special asymmetric wettability and efficient photothermal properties, is constructed via a controllable surface/interface engineering strategy. The surface temperature of the copper foam rises rapidly under light irradiation, thereby reducing the viscosity of the contacting crude oil in situ. Simultaneously, the special oleophobic/oleophilic asymmetric wettability generates a strong internal driving force via a surface energy gradient, which facilitates the unidirectional transport of crude oil. By combining directional transport with photothermal properties, this engineered Janus system enables rapid adsorption and collection of offshore crude oil. Furthermore, integrated with a peristaltic pump to form a "self-heating vacuum cleaner" system, the photothermal Janus copper foam achieves continuous and efficient cleanup of crude oil from seawater.