Facile one-step fabrication of highly hydrophobic, renewable and mechanically flexible sponge with dynamic coating for efficient oil/water separation

•Highly-hydrophobic Cu-NPs coated sponge was one-step fabricated without any modification.•The dynamic Cu-NPs coating provides sponge an excellent renewability.•The coated sponge exhibits high open-pore structure and great mechanical property.•The coated sponge shows excellent striking absorption capacities and separation efficiencies.•The coated sponge can be used for oil/water separation at static and dynamic states.