Superhydrophobic polymer multilayers for the filtration- and absorption-based separation of oil/water mixtures

Abstract

We report layer-by-layer approaches to the design of superhydrophobic and superoleophilic substrates for the filtration- or absorption-based separation of bulk oil from oil/water mixtures. Fabrication of covalently cross-linked, nanoporous polymer multilayers on mesh substrates yielded superhydrophobic and superoleophilic porous media that allow oil to pass, but completely prevent the passage of bulk water. This approach can be used to promote the filtration of oil/water mixtures, and these film-coated substrates can be bent and physically manipulated without affecting oil- and water-wetting properties. Fabrication on three-dimensional macroporous polymer pads yielded flexible objects that float on water and absorb oil at contaminated air/water interfaces. This approach permits oil to be recovered by squeezing or rinsing with solvent and the reuse of these materials without decreases in performance. These pads can also absorb oil from simulated seawater, brine, and other media representative of marine or industrial contexts where oil contamination can occur. Our results address issues associated with the design of polymer-based coatings for the separation, removal, and collection of oil from oil-contaminated water. With further development, this approach could provide low-energy alternatives to conventional remediation methods or yield new strategies that can be implemented in ways that are impractical using current technologies. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3127–3136.