Stimuli-responsive materials with switchable wettability for bidirectional oil-water separation show great potential in practical applications. Inspired by mussels, we use dopamine as an anchor molecule to construct a polydopamine (PDA) coating on the surface of copper foam (CF). Silver particles are deposited on the PDA coated surface to construct a multiscale composite structure, and the long-chain alkylthiol with carboxyl and methyl groups at the end is subsequently self-assembled to the modified copper foam surface. The as-modified copper foam has unique pH responsiveness, that is, the water contact angle (WCA) is measured to be about 140° under acidic and neutral conditions, while alkaline conditions radically change the surface property from superhydrophobic to superhydrophilic due to the measured WCA turning to 0°. It can be used efficiently for the bidirectional separation of an oil-water mixture, e.g., the separation efficiency of a 1,2-dichloroethane/water mixture can reach as high as 98.2%. Besides, it maintains 98% separation efficiency and stable wettability for an octane/water mixture, together with excellent mechanical durability; the WCA of the surface maintains at about 130° after ten wear cycles.

用于双向油水分离的具有可切换润湿性的刺激响应材料在实际应用中显示出巨大的潜力。受贻贝的启发，我们使用多巴胺作为锚定分子，在泡沫铜 (CF) 表面构建聚多巴胺 (PDA) 涂层。银粒子沉积在PDA涂层表面以构建多尺度复合结构，末端带有羧基和甲基的长链烷基硫醇随后自组装到改性泡沫铜表面。改性后的泡沫铜具有独特的 pH 响应性，即在酸性和中性条件下测得的水接触角 (WCA) 约为 140°，而在碱性条件下，由于测得的表面性质从超疏水转变为超亲水。 WCA 转向 0°。可高效用于油水混合物的双向分离，如1,2-二氯乙烷/水混合物的分离效率高达98.2%。此外，它对辛烷/水混合物保持98%的分离效率和稳定的润湿性，以及优异的机械耐久性；经过十次磨损循环后，表面的 WCA 保持在大约 130°。