Robust and durable self-healing superhydrophobic polymer-coated MWCNT film for highly efficient emulsion separation

The discharge of large amounts of oily wastewater causes serious environmental pollution and is a threat to human health. It is therefore necessary to develop products to deal with the challenges posed by such wastewater discharges. One important area is the separation of oil/water emulsions. In this study, a modified multi-walled carbon nanotube film was fabricated. Polydivinylbenzene decoration and a POTS (1H,1H,2H,2H-perfluorooctyltriethoxysilane) layer were formed by a solvothermal method and chemical vapor deposition, respectively. The film had outstanding superhydrophobicity and demulsification, separated water-in-oil emulsions with high efficiency (99.98% for water-in-chloroform emulsion), and high reusability (above 99.7% after 20 cycles). Because of its self-healing ability, the film can maintain its superhydrophobicity after severe damage caused by O2 plasma treatment. These features make the film suitable for practical sewage treatment. The self-healing mechanism is also discussed in this article.