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Bioinspired design of underwater superoleophobic Poly(N-isopropylacrylamide)/ polyacrylonitrile/TiO2 nanofibrous membranes for highly efficient oil/water separation and photocatalysis

Sun, Fei, Ren, Hai-Tao, Li, Ting-Ting, Huang, Shih-Yu, Zhang, Yue, Lou, Ching-Wen, Lin, Jia-Horng
Environmental research 2020 v.186 pp. 109494
chemical composition, contact angle, hydrophilicity, mechanical properties, mechanical stress, methylene chloride, nanofibers, oils, petroleum, photocatalysis, polyacrylonitrile, rhodamines, scales (integument), temperature, thermal properties, titanium dioxide, ultraviolet radiation, wastewater treatment, wettability
Inspired by fish scales, this study prepares a thermo-responsive underwater oleophobic PNIPAM/PAN/TiO₂ nanofibrous membranes by traditional electrospinning technique using poly-N-isopropylacrylamide (PNIPAM) and polyacrylonitrile (PAN). Thermal properties, mechanical properties, surface chemical composition, wettability, photocatalysis, and oil/water separation of PNIPAM/PAN/TiO₂ membrane are explored compared to pure PNIPAM membrane. Result reveals that PAN/TiO₂ compounds make PNIPAM membrane with a smaller fiber diameter of 141 nm and high tensile stress of 7.4 MPa, and also decompose 98% of rhodamine B after UV light radiation. This bioinspired design structure endows the membrane with superhydrophilicity with a low water contact angle, and underwater superoleophobicity with a high oil contact angle of 157° (petroleum ether) and 151° (dichloromethane). This membrane can efficiency separate oil/water mixture with a high separation efficiency. Moreover, the resultant PNIPAM/PAN/TiO₂ membrane has the bionic fish scale structure, and has wettability respond at lower critical solution temperature making the water flux decreased from 10013 ± 367 L m⁻²·h⁻¹ to 7713 ± 324 L m⁻²·h⁻¹, and thus has a potential to be used in purification of reclaimed water and separation of oil from water.