Bo Ge

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.

A versatile approach to produce superhydrophobic materials used for oil-water separation.

Designing functional materials that can be used for oil-water separation in an efficient and cost-effective process is highly desired yet still challenging. Herein, three functional materials used for oil-water separation are readily produced by a dip coating process. Three typical porous materials including copper mesh, fabric, and sponge were dipped into the solution of polyfluorowax-hydrophobic SiO2 to alter their surface texture and chemistry, allowing them to exhibit superhydrophobic property. It was found that the resulting superhydrophobic copper mesh and fabric can be used as a membrane to separate oil-water mixture efficiency; while the obtained superhydrophobic sponge was demonstrated as an oil sorbent scaffold to absorb oil from the oil-water mixture selectively. More importantly, these superhydrophobic materials can retain their oil-water separation efficiency even after 10 cycles of oil-water separation.

Designing transparent superamphiphobic coatings directed by carbon nanotubes

Creating surfaces with superamphiphobic property and optical transparency simultaneously would have fundamental and practical significance but has been proven extremely challenging. Herein, we develop a transparent superamphiphobic coating using carbon nanotubes (CNTs) as the template by a facile approach. CNTs enwrapped with SiO2 coating was produced by a sol-gel method and then sprayed onto the glass slides to form coatings. Subsequent thermal treatment and surface fluoration allowed the sprayed coating to exhibit enhanced transparency across a broad spectrum of ultraviolet and visible wavelengths and also display superrepellency toward water and a number of organic liquids, such as dodecane. The obtained transparent coating can sustain its superamphiphobicity even after thermal treatment at 400 °C. Separate experiment demonstrated that the CNTs-directed geometrical structure played a key role in establishing superamphiphobicity.

A superhydrophobic monolithic material with tunable wettability for oil and water separation

Abstract The development of a convenient method for oil-removal is of great significance for environmental protection. Here, we present a simple method for the removal of oils from water surface based on sponges that we fabricated by solution-immersion processes. The sponges exhibited high selectivity and absorption capacities for various kinds of oils when they were employed as absorptive materials. More importantly, the superhydrophobic sponge could be sustained 400 cycles of compressing test without losing their superhydrophobicity, exhibiting the high elasticity, robustness, and durability. To extend application field, superhydrophobic filter paper was used for oil–water separation. Interestingly, tunable wettability was received when oleophobic silica was employed instead of hydrophobic silica. We expected that this low-cost process can be used for oil-spill cleanup.

One-pot, template-free synthesis of a robust superhydrophobic polymer monolith with an adjustable hierarchical porous structure

We fabricated a porous polymer monolith with tunable hierarchical porosity and damage-tolerant superhydrophobic properties simultaneously using divinylbenzene (DVB) and SiO2 composites. The polymer monolith exhibiting a high specific surface area (820.5 m2 g−1) and large pore volume (1.59 cm3 g−1) is obtained without using any fluorinated compounds, template, surfactant or stabilizer and further chemical modification which is green, low cost, simple and environmentally-safe. The hierarchical porosity of the polymer monolith is controllable readily by regulating the solvothermal temperature. In addition, the polymer monolith features excellent superhydrophobicity with a water contact angle of 161.3° and a sliding angle smaller than 4.0° as well as switchable wettability which can be realized by simple UV irradiation and abrasion. Importantly, the monolith demonstrates excellent mechanical resistance and environmental durability owing to its low-surface-energy microstructures extending throughout its whole volume which is comparable to most superhydrophobic surfaces that have poor durability. Moreover, the monolith can be used as a chalk for painting superhydrophobic porous polymer coating on substrates with various shapes and features, which facilitates the preparation of large area superhydrophobic surfaces and is extensively applicable.

A simple way to an ultra-robust superhydrophobic fabric with mechanical stability, UV durability, and UV shielding property

HYPOTHESIS Development of an ultra-robust superhydrophobic fabric with mechanical stability, UV durability, and UV shielding by a simple method is highly desirable, yet it remains a challenge that current technologies have been unable to fully address. EXPERIMENTS Herein, the original fabric is immersed into the solution containing ZnO nanoparticle and PDMS (polydimethylsiloxane), and the fiber surfaces are uniformly covered by a ZnO-PDMS layer after thermal treatment at 110 °C for 30 min. FINDINGS Droplets of water and corrosive liquids including strong acid, strong alkali, and saturated salt solution display sphere shape on the ZnO-PDMS coated fabric surface. The stable binding of ZnO-PDMS layer onto the fibers allows for the fabric coating with robust superhydrophobicity, and the coated fabric still displays superhydrophobicity after hand twisting, knife scratching, finger touching, and even cycles of sandpaper abrasion. The ZnO-PDMS coated fabric can also keep its superhydrophobic property when exposed to long term UV illumination, demonstrating its UV resistance. Moreover, the uniformly distribution of ZnO nanoparticles on fibers allows the ZnO-PDMS coated fabric to display UV shielding property.

One-step foaming method to functional polyurethane absorbents foam

ABSTRACT Traditional preparation of superhydrophobic absorbents relies on solvents or further modification with silane. For environmental reasons, it is ideal to find ways that reduce or completely non-solvent. Herein, we show that superhydrophobic sponges can be obtained without solvents by the foaming process. Rough surface morphology and low surface energy were achieved simultaneously during the formation of superhydrophobic foam without further modification. The time required for oil–water separation was shortened significantly, when combined the sponge with a vacuum system. Importantly, the obtained sponge can retain its high oil absorption capacity after several cycles of oil–water separation. The sponge is easy to be scaled up and we have fabricated foams in large scale (37 cm × 30 cm × 22 cm) for making it an ideal candidate for practical application.