Study on the Mechanism of Rapid Oil‐Water Separation by a Fe3O4@PMMA@PDMS Intelligent Superhydrophobic Micro/Nanorobot

Abstract We prepared an environmentally friendly intelligent Fe 3 O 4 @PMMA@PDMS superhydrophobic oil‐absorbing material with simple process and excellent performance, and investigated the effects of different particle sizes of Fe 3 O 4 , different concentrations of PDMS, and different heating times on the superhydrophobicity of the coating. The best performance of the coating was achieved at a particle size combination of 20/500 nm for Fe 3 O 4 , a PDMS to Fe 3 O 4 @PMMA mass ratio of 6 : 1, and a heating time of 2 min at 400 °C. H2‐SPSS coating not only has excellent superhydrophobicity, abrasion resistance, self‐cleaning property, and chemical corrosion, but also has good flux and efficiency for separating oil‐water mixture, with fluxes of 40,540, 32,432, and 37,027 Lm −2 h −1 for trichloromethane, dichloromethane and bromoethane, respectively, and separation efficiencies of 99.78 %, 99.74 % and 99.73 %, respectively. In addition, we also prepared a superhydrophobic magnetic polyurethane (SPPU) sponge using Fe 3 O 4 @PMMA@PDMS, which not only has a good oil absorption capacity of 18–44 g/g for different oil substances, it can also move directionally by magnet attraction and absorb oil along a fixed path. Under the control of the magnet, SPPU completes the whole oil absorption process in only 4 s, showing excellent oil absorption and intelligence.