Superhydrophobic Carbon Nanotube–Metal Rubber Composites for Emulsion Separation

Poor mechanical stability of the superhydrophobic surface is the fundamental reason that limits its wide application. In the present study, metal rubber (MR) with a three-dimensional elastic porous characteristic was applied as the substrate. Multiwalled carbon nanotubes (MWCNTs) were filled into the pores of MR through suction and filtration of the MWCNTs suspension. Using an in situ bonding method, MWCNTs were anchored in the MR pores by poly(dimethylsiloxane) (PDMS). Consequently, a type of superhydrophobic material with a three-dimensional network frame protection was constructed. The emulsion separation mechanism of superhydrophobic MR was investigated using the plane random segmentation theory and theoretical model of deep filtration. By analysis of the depth retention effect in the separation process, the separation efficiency of the emulsion was predicted. In addition, the results show that the prepared superhydrophobic MR had an excellent purification capability for a water-in-lubricating oil emulsion and outstanding mechanical and chemical stability.