Facile Fabrication of Superhydrophobic Sponge with Selective Absorption and Collection of Oil from Water

A simple vapor-phase deposition process has been developed to fabricate a superhydrophobic and superoleophilic sponge using ordinary commercial polyurethane sponges. The simultaneous properties of superhydrophobicity and superoleophilicity enable the sponge to float on the water surface and selectively absorb oil from water. Its uptake capacities of different oils (motor oil, lubricating oil, pump oil, silicone oil, and soybean oil) in the oil–water mixtures were all above 20 g/g. The absorbed oil could be collected by squeezing the sponge, and the recovered sponge could be reused in oil–water separation for many cycles while still maintaining a high capacity. This is helpful for realizing the proper disposal of the oil and avoiding secondary pollution. A similar experiment was performed using the as-prepared sponge to remove petroleum from contaminated water. The results suggest that our material might find practical applications in the cleanup of oil spills and the removal of organic pollutants from water surfaces

Facile Fabrication of Superhydrophobic Sponge with Selective Absorption and Collection of Oil from Water

A simple vapor-phase deposition process has been developed to fabricate a superhydrophobic and superoleophilic sponge using ordinary commercial polyurethane sponges. The simultaneous properties of superhydrophobicity and superoleophilicity enable the sponge to float on the water surface and selectively absorb oil from water. Its uptake capacities of different oils (motor oil, lubricating oil, pump oil, silicone oil, and soybean oil) in the oil–water mixtures were all above 20 g/g. The absorbed oil could be collected by squeezing the sponge, and the recovered sponge could be reused in oil–water separation for many cycles while still maintaining a high capacity. This is helpful for realizing the proper disposal of the oil and avoiding secondary pollution. A similar experiment was performed using the as-prepared sponge to remove petroleum from contaminated water. The results suggest that our material might find practical applications in the cleanup of oil spills and the removal of organic pollutants from water surfaces

Robust and Durable Superhydrophobic Cotton Fabrics for Oil/Water Separation

By introducing the incorporation of polyaniline and fluorinated alkyl silane to the cotton fabric via a facile vapor phase deposition process, the fabric surface possessed superhydrophobicity with the water contact angle of 156° and superoleophilicity with the oil contact angle of 0°. The as-prepared fabric can be applied as effective materials for the separation of water and oil mixture with separation efficiency as high as 97.8%. Compared with other materials for oil/water separation, the reported process was simple, time-saving, and repeatable for at least 30 times. Moreover, the obtained fabric kept stable superhydrophobicity and high separation efficiency under extreme environment conditions of high temperature, high humidity, strong acidic or alkaline solutions, and mechanical forces. Therefore, this reported fabric has the advantages of scalable fabrication, high separation efficiency, stable recyclability, and excellent durability, exhibiting the strong potential for industrial production

Robust and Durable Superhydrophobic Cotton Fabrics for Oil/Water Separation

By introducing the incorporation of polyaniline and fluorinated alkyl silane to the cotton fabric via a facile vapor phase deposition process, the fabric surface possessed superhydrophobicity with the water contact angle of 156° and superoleophilicity with the oil contact angle of 0°. The as-prepared fabric can be applied as effective materials for the separation of water and oil mixture with separation efficiency as high as 97.8%. Compared with other materials for oil/water separation, the reported process was simple, time-saving, and repeatable for at least 30 times. Moreover, the obtained fabric kept stable superhydrophobicity and high separation efficiency under extreme environment conditions of high temperature, high humidity, strong acidic or alkaline solutions, and mechanical forces. Therefore, this reported fabric has the advantages of scalable fabrication, high separation efficiency, stable recyclability, and excellent durability, exhibiting the strong potential for industrial production

Air Cushion Convection Inhibiting Icing of Self-Cleaning Surfaces

Anti-icing surfaces/interfaces are of considerable importance in various engineering fields under natural freezing environment. Although superhydrophobic self-cleaning surfaces show good anti-icing potentials, promotion of these surfaces in engineering applications seems to enter a “bottleneck” stage. One of the key issues is the intrinsic relationship between superhydrophobicity and icephobicity is unclear, and the dynamic action mechanism of “air cushion” (a key internal factor for superhydrophobicity) on icing suppression was largely ignored. Here we report that icing inhibition (i.e., icing-delay) of self-cleaning surfaces is mainly ascribed to air cushion and its convection. We experimentally found air cushion on the porous self-cleaning coating under vacuum environments and on the water/ice-coating interface at low temperatures. The icing-delay performances of porous self-cleaning surfaces compared with bare substrate, up to 10–40 min under 0 to ∼−4 °C environments close to freezing rain, have been accurately real-time recorded by a novel synergy method including high-speed photography and strain sensing voltage. Based on the experimental results, we innovatively propose a physical model of “air cushion convection inhibiting icing”, which envisages both the static action of trapped air pocket without air flow and dynamic action of air cushion convection. Gibbs free energy of water droplets increased with the entropy of air derived from heat and mass transfer between warmer air underneath water droplets and colder surrounding air, resulting in remarkable ice nucleation delay. Only when air cushion convection disappears can ice nucleation be triggered on suitable Gibbs free energy conditions. The fundamental understanding of air cushion on anti-icing is an important step toward designing optimal anti-icing surfaces for practical engineering application