Durable ER@SiO2@PDMS superhydrophobic composite designed by double crosslinking strategy for efficient oil-water separation

The mechanical weakness and costly complex fabrication are major obstacles for the practical applications of superhydrophobic coatings for oil-water separation. Herein, we demonstrate a low-cost and scalable fabrication of a durable superhydrophobic composite with complex multilayered architecture, where silica nanoparticles (SiO 2 NPs) are confined within epoxy resin (ER) layers, providing proper roughness, and an outermost low-surface-energy layer of polydimethylsiloxane (PDMS) is coated, enhancing the superhydrophobicity. Benefitting from the multilayered structure, the manifests excellent water repellency and durability to mechanical and chemical damage. When evaluated as an absorbent for oil-water separation, the composite demonstrates remarkable separating ability, with the separating efficiency before and after mechanical damage reaching >98%. The multilayered superhydrophobic composite with tailored mechanical properties opens new possibilities for the development of robust superhydrophobic materials for oil absorption applications. We design and develop an ER@SiO 2 @PDMS superhydrophobic composite using a “adhesive + NPs + adhesive” double crosslinking strategy. Specifically, SiO 2 NPs are confined within ER layers to control the surface roughness, while PDMS is employed as the cross-linked hydrophobic coating. When evaluated as an absorbent for oil-water separation, the composite demonstrates remarkable separating ability, exhibiting high efficiency. • We design and fabricate an ER@SiO 2 @PDMS superhydrophobic composite by using the double crosslinking strategy. • The NPs are confined within ER layers to control surface roughness, while PDMS is employed as superhydrophobic coating. • The influence of the layer number and ER to ethanol ratio on WCA is investigated. • The as-prepared ER@SiO 2 @PDMS superhydrophobic composite demonstrates remarkable separating efficiency.