Highly ordered architectures with roughness and porous surface are the key challenges toward developing smart superwetting membranes. We prepared switchable superwetting Cu(OH) 2 @ZIF-8 core/shell nanowire membranes for high-flux oil/ water separation as well as simultaneous heavy-metal ions removal in one step. The well-defined Cu(OH) 2 @ZIF-8 core/shell nanowire grown on copper mesh with average length of ca. 15 μm and diameter of ca. 162 nm exhibits high water contact angle (CA) of ca. 153 ± 0.6°. After modified by ethanol, the membrane holds the reverse superwettability with oil (dichloromethane as an example) CA of ca. 155 ± 0.8°underwater. The separation efficiencies of the membranes are higher than that of 97.2% with a remarkable flux rate higher than 90 000 L m −2 h −1 for the immiscible oil/water mixture. And the removal efficiency for Cr 3+ ions at 10 ppb can arrive at 99.2 wt % in the toluene-in-water emulsion. The high performances of the smart superwetting membranes can be attributed to the interfacial capillary effects of the hierarchical Cu(OH) 2 @ZIF-8 core/shell nanostructures. This work may provide a new insight into the design of smart superwetting surfaces for oil/water separation and target adsorption in one step.

In nature, leaf photosynthesis is the most common solar energy conversion system, which involves light absorption and conversion processes. Most interestingly, the leaves of a green plant are almost lamellar. Herein, inspired by the structure and light conversion capacity of plants, we developed a Crassula perforata-structured CuO@CuS/poly­(dimethylsiloxane) (CuO@CuS/PDMS) nanowire arrays (NWAs) on copper foam (CF) with effective light-to-heat conversion to clean up viscous crude oil (∼105 mPa s) by in situ reducing the viscosity of crude oil. The C. perforata-structured CuO@CuS/PDMS core/shell NWAs were grown on copper foam with high density and uniformity, exhibiting excellent light adsorption and photothermal conversion efficiency. When simulated sunlight was irradiated on the structure of the CuO@CuS/PDMS NWAs/CF, abundant heat was generated and in situ reduced the viscosity of crude oil, which prominently increased the oil diffusion coefficient and sped up the oil sorption rate. The oil recovery procedure can realize a continuous clean up with the assistance of a pump device, and the crude oil adsorption capacity can reach up to 15.57 × 105 g/m3 during a 5 min adsorption process. The high-performance photothermal self-heated superoleophilic CuO@CuS/PDMS NWAs/CF has a promise of promoting the practical applications of the sorbents in the clean up of viscous crude oil spills.

Studies which regulate macroscopic wetting states on determined surfaces in multiphase media are of far-reaching significance but are still in the preliminary stage. Herein, inspired by the wettability subassembly of fish scales, Namib desert beetle shell, and lotus leaf upper side, interfaces in the air–water–oil system are programmed by defect engineering to tailor the anti-wetting evolution from double to triple liquid repellency states. By controlling the visible light irradiation and plasma treatment, surface oxygen vacancies on Cu x O@TiO2 nanowires (NWs) can be healed or reconstructed. The original membrane or the membrane after plasma treatment possesses abundant surface oxygen vacancies, and the homogeneous hydrophilic membrane shows only double anti-wetting states in the water–oil system. By the unsaturated visible light irradiation time, the surface oxygen vacancy partially healed, the heterogeneous hydrophilic–hydrophobic components occupied the membrane surface, and the anti-wetting state finally changed from double to triple in the air–water–oil system. After the illumination time reaches saturation, it promotes the healing of all surface oxygen vacancies, and the membrane surface only contains uniform hydrophobic components and only maintains double anti-wetting state in the air–oil system. The mechanism of the triple anti-wetting state on a heterogeneous surface is expounded by establishing a wetting model. The wetting state and the adhesion state of the Cu x O@TiO2 NW membrane show regional specificity by controlling the illumination time and region. The underwater oil droplets exhibit the “non-adhesive” and “adhesive” state in a region with unsaturated irradiation time or in an unirradiated region, respectively. Underwater oil droplet manipulation can be accomplished easily based on switchable wettability and adhesion. Current studies reveal that defect engineering can be extended to anti-wetting evolution in the air–water–oil system. Constructing an anti-wetting interface by heterogeneous components provides reference for designing the novel anti-wetting interface.

Removal rate and durability are the two most important parameters of an ideal air purification filter to remove inhalable particles and toxic gases. Here, based on the interaction of a local electric field and an external electric field, a novel coaxial core–shell CuO@NH2-MIL-53(Al) nanowire array was synthesized on a rigid copper net, which was used to remove PM2.5 and SO2 simultaneously. The removal rates of PM2.5 by the filter with and without an external electric field can reach 98.72% and 44.41%, respectively, and the adsorption capacity of SO2 can reach 4.87 mol/m2. After repeated filtration and cleaning for 10 cycles, the air pollution removal efficiency can be kept almost stable.