Facile preparation of superhydrophobic melamine foam via one-pot emulsion polymerization for efficient oil/water separation

Superhydrophobic materials for efficient oil/water separation have significant industrial application value, but their preparation through low-cost and simple strategy is still a great challenge. Herein, melamine foam (MF) was superhydrophobically modified by polydimethylsiloxane (PDMS) through one-pot emulsion polymerization. The nanospheres generated via emulsion polymerization in-situ formed micro-nanostructures on the MF skeleton. During emulsion polymerization, the crosslinking between PDMS was simultaneously carried out to form a hydrophobic layer on the surface of the skeleton. The modified MF was superhydrophobic (the water contact angle and rolling angle were 156.8° and 3°, respectively), had high saturated absorption capacities (61.49–122.73 g/g), and separation efficiency > 99.5% for various oils/organic solvents. Moreover, the foam featured excellent chemical/physical stability, and the surface wettability did not change significantly for acidic (pH = 1), basic (pH = 13), or saturated NaCl solutions or when sonicated. Meanwhile, the foam can continuously separate oil/water mixtures with the assistance of vacuum pump. Furthermore, our foam can also effectively separate the surfactant-stabilized emulsion via simply mechanical compression strategy. These results open an alternative and simple route for treating oily wastewater in practice.