Mussel-inspired V-shaped copolymer coating for intelligent oil/water separation

•Smart surface was fabricated based on mussel-inspired chemistry.•V-shaped brush leads the surface to be highly and independently stimuli-responsivity.•Gravity-driven pH switchable oil/water separations were realized.•Reversible oil capture and release were achieved.

Successful fabrication of mussel-inspired V-shaped copolymer based materials for pH controllable oil/water separation was reported. Triblock copolymer, polydimethylsiloxane-block-poly(2-hydroxyethyl methacrylate)-block-poly(2-(dimethylamino)ethyl methacrylate) (PDMS-b-PHEMA-b-PDMAEMA) was designed and synthesized through copper(0)-mediated reversible-deactivation radical polymerization (RDRP). Hydroxyl-containing PHEMA block enabled the covalent reaction to occur between polymer and polydopamine (PDA) functionalized substrates. The mixed polymer brushes of oleophilic/hydrophobic PDMS and pH-responsive PDMAEMA endowed the substrates with good pH responsive oil/water wettability and stability. As a proof of concept, the functionalized mesh can separate a range of different immiscible oil/water mixtures with high separation efficiency over 98.5% and high oil flux of 8800-9500 L h−1 m−2 and water flux of 7400-7800 L h−1 m−2. Additionally, the functionalized sponge realized reversible oil capture and release in aqueous media. Because dopamine through self-polymerization can form strong adhesive films on inorganic and organic substrates in alkalescence solution, the method used in current contribution would be also suitable for producing polymer brush functionalized intelligent materials based on other common substrates.

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