Pickering High Internal Phase Emulsions Templated Super-Hydrophobic–Oleophilic Elastic Foams for Highly Efficient Oil/Water Separation

We report a facile method to fabricate highly porous, elastic poly(butyl acrylate) (PBA)-based foams with excellent oil absorption capacity, anti-fouling property, and reusability templated by water-in-oil (w/o) Pickering high internal phase emulsions (HIPEs), stabilized by hydrophobic silica nanoparticles. Specifically, additional polydimethylsiloxane (PDMS) droplets were introduced in the emulsification system for enhancing the multifunctionality of fabricated polyHIPEs. The synergistic effect between micro–nano hierarchical structure and low surface energy endows the prepared foams with superhydrophobicity (>160° water contact angle) and superoleophilicity, both inside and outside, which also confers environmental stability to the material. Due to the tailored pore size and open-cell structure, the porous materials have self-cleaning property as well as high oil absorptivity, which are antifouling for diverse contaminants and can rapidly absorb a large amount of oil by swelling. In addition, the foams can be recycled and reused directly after each recovery of absorbed oil by simply squeezing due to the excellent compression-resilience property. Since PBA has a low glass transition temperature (Tg), the as-prepared PBA-PDMS foams are particularly applicable to use in cold conditions.