Abstract

Efficient oil–water separation has been a significant research focus in the field of environmental science. In this study, superhydrophobic nickel foam (NCH/NF/PDMS) with controllable multiscale microstructure was successfully prepared using an in situ hydrothermal synthesis method with a facile adjustment of raw material ratios. Inspired by the delicate multiscale structure of Wodyetia bifurcata, we finally designed and prepared a multistage structured superhydrophobic nickel foam Co2Ni1/NF/PDMS with a needle-like bottom structure complemented by nanoflower structures for efficient oil–water separation applications. This unique multi-stage structure not only significantly reduces the actual contact area between the water and the surface but also induces significant capillarity at the nanoscale. This facilitates the preferential propagation of the oil phase through the pores, while the water phase is repelled due to the higher contact angle and low surface energy, resulting in highly efficient oil–water separation. Experimental results demonstrated that Co2Ni1/NF/PDMS exhibited excellent performance in separating various oil–water mixtures and emulsions. After 100 cycles of separation, the separation efficiency of Co2Ni1/NF/PDMS for 1,2-dichloroethane/water mixtures remained at 98.8?%, with an oil flux exceeding 8235 L·m^?2·h^?1. For carbon tetrachloride W/O emulsions, the separation efficiency reached 99.32?% with a flux of 805 L·m^?2·h^?1. Additionally, Co2Ni1/NF/PDMS maintained stable superhydrophobicity under various mechanical deformations. This outstanding superhydrophobicity endowed the material with a delayed icing tendency, effectively reducing the nucleation rate of heterogeneous materials. Electrochemical tests also revealed that the prepared superhydrophobic surfaces possess excellent corrosion resistance and remarkable durability. This study provides a new design strategy for the development of efficient oil–water separation materials, underscoring the potential for optimizing separation performance through modulation of microstructure and surface properties.