Superhydrophilic and Underwater Superoleophobic Poly(propylene) Nonwoven Coated with TiO₂ by Atomic Layer Deposition

To develop an effective and convenient solution for underwater repelling oil and cleaning up oily water, TiO₂ nano-coating is deposited on the surface of poly(propylene) nonwoven (PPN) by atomic layer deposition (ALD). There is no evident change in the morphologies comparing ALD-modified PPN with PPN except for thickness. For oils of different densities, such as 1,2-dichloroethane, methylene chloride, chloroform, carbon tetrachloride, n-hexane, and petroleum ether, the underwater oil contact angle and underwater oil sliding angle of ALD-modified PPN range from 152.25° to 156.19° and 5.63° to 8.80°, respectively, exhibiting superior superhydrophilicity and underwater superoleophobicity. Notably, ALD-modified PPN shows a high chemical stability in different solutions, such as acid, alkali, salt, and polar solvent, which even can slightly improve the underwater superoleophobicity of TiO₂ nano-coating. The excellent underwater anti-oil property, self-cleaning property, robust chemical resistance, and easily scaled-up preparation process of TiO₂-coated PPN suggest great potential for practical applications in the energy, environmental protection, marine anti-fouling, and microflow control fields.