A facile method for the fabrication of a superhydrophobic polydopamine-coated copper foam for oil/water separation

Abstract

A simple dip-coating method was explored to construct hierarchical structures on a 3D copper foam (CF) surface by combining the intrinsic properties of mussel-inspired polydopamine (PDA) and a 3D metal structure. The CF substrate was sequentially modified with PDA and Ag nanoparticles (NPs) and then coupled with n-dodecyl mercaptan (NDM) to create a durable superhydrophobic CF for oil/water separation. The morphology, chemical composition and wettability of the fabricated modified CF surface were characterized. The modified CF surface possesses an increased roughness and exhibits superhydrophobicity, with water contact angle values greater than 150°. The PDA coating on the CF surface can reduce silver ions and anchor the formed NPs onto the surface to construct the hierarchical structure of the superhydrophobic CF. Furthermore, the oil/water separation properties were also investigated. The modified CF can separate a series of oil/water mixtures with a high efficiency and relatively high intrusion pressure. More importantly, the modified CF retains its high efficiency after 30 repeated uses (more than 98% for a dodecane/water mixture), exhibiting excellent durability. The mechanism of oil/water separation is also discussed. The results of this study indicate that the modified CF can serve as a promising candidate for the large-scale separation of oily pollutants from water.