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The utilization of solar energy for steam generation is a highly efficient and sustainable technology for seawater desalination to solve the long-standing water crisis. Carbon-based materials have shown promising thermal-heat conversion efficiency due to their broadband solar absorption. Herein, carbon black (CB) was combined with polydopamine (PDA) to develop a high-performance, low-cost, and scalable PDA/CB@PP composite non-woven fabric was fabricated by dip-coating of CB and in situ polymerization of PDA. The hierarchical structure constructed on the fiber surface and the synergetic effects of CB and PDA contributed to the high light absorbance (>95%), superhydrophilicity, and high energy conversion efficiency. The one-way fluidic PDA/CB@PP photothermal based solar steam evaporator demonstrated a high evaporation rate of 1.68 kg m-2h−1 with a solar steam efficiency of 91.5%. Moreover, the PDA/CB@PP fabric shows remarkable salt resistance when purifying seawater because of the water channel preserved by the hydrophilic porous structure of the fabric which could provide sustained water supply. Besides, the PDA/CB@PP fabric possesses excellent purification capability to wastewaters contaminated by heavy-metal and chemical dyes. This study provides insights into the design and development of low-cost, scalable, highly stable, and efficient solar steam generators for seawater desalination and wastewater purification.

Solar steam generation is an efficient way of harvesting solar energy for water purification. Developing a versatile solar absorber with salt resistance and the capability to purify an oil-in-water emulsion is a grand challenge. Herein, a polypropylene (PP) nonwoven fabric-based photothermal absorber is fabricated by the combination of carbon nanotubes (CNTs), polypyrrole (PPy), and a fluorinated hydrophobic coating in a layer-by-layer approach. The specially designed architecture displays a hierarchical microstructure and Janus wetting properties, facilitating solar absorption and heat generation on the evaporation surface, and can effectively prevent salt crystallization. The water layer formed on the superhydrophilic/underwater superoleophobic bottom surface could repel oil droplets and form a channel to advect concentrated salt back into bulk water, which enabled high purity separation of an oil-in-water emulsion and continuous desalinization of seawater without the reduction of the evaporation rate. As a result, the solar absorber can achieve a remarkable evaporation rate of 1.61 kg m-2 h-1 and an energy efficiency of 91.2% under 1 sun irradiation and shows extraordinary performance in the purification of contaminated wastewater (over 99.8% purity). The strategy proposed provides a pathway for developing versatile high-performance solar absorbers for the sustainable treatment of saline water, wastewater, and oil-containing water.

High-performance low-cost superhydrophobic sponges are desired for selective recycling of leaking oils from open water. Herein, an ingenious method is proposed to fabricate an ultrathin superhydrophobic coating layer on a commercial sponge. The coating layer is composed of a shish-kebab-structured porous ultrahigh molecular weight polyethylene (UHMWPE) film that is fabricated from a UHMWPE/xylene solution by shear flow-induced crystallization. A strong relationship between the shish-kebab crystallite morphology and the superwetting performance is confirmed. The UHMWPE coating layer fabricated at a 900 rpm rotation rate possesses a lamellae size of 95.1 nm and a lamellae distance of 27.4 nm, which lead to a high water contact angle of 157° and a low contact angle hysteresis of 4.5°. The UHMWPE layer prepared in 4 min of treatment is thick enough to prevent the intrusion of water even under vacuum and remain superoleophilic. The developed UHMWPE-coated sponge (UCS) exhibited a high absorption capability of 70-191 g/g toward various oils and solvents, which is comparable with the neat melamine sponge. Its excellent compressibility and durability enabled fast recovery of absorbed oil with a high recovery rate (over 85%) by mechanical squeezing. The UCS could be assembled into small devices to selectively collect oil from open water and a water/oil mixture using a pump, which manifests its promising practical applicability. Apart from these extraordinary properties, the approach developed has the lowest material cost and the shortest processing time hitherto.

Precise control and regulation of the cell structure in supercritical CO2 (scCO2) foaming is the key to boost the performance and extend the application of polymer foams. In this work, dynamic scCO2 foaming method is proposed to fabricate thermoplastic polyurethane (TPU) foams with unique wrinkly structures by introducing a continuous scCO2 flow field during scCO2 saturation. The scCO2 flow field applied on the TPU matrix generated intramolecular stress and resulted in the formation of wrinkles on the surface of cells. The structure of wrinkles was controlled by pivotal processing factors including foaming temperature, pressure, scCO2 flow rate, and scCO2 flow time. Attributing to the wrinkly structure, the wrinkled foams possessed superior compressive modulus, strength, recoverability, and energy absorption performance than conventional TPU foams, which make them a promising material for buffering and energy absorption applications. The dynamic scCO2 foaming method opens avenue for scCO2 foaming process involves dynamic field.

In nature, the water-repellent surface of a superhydrophobic material such as lotus has the micro/nano hierarchical structure, while shish-kebab, which is one of the most fascinating superstructure crystals in polymer science, also exhibits micro/nano hierarchical structure. Accordingly, it remains an idea of whether this structure can be used as the superhydrophobic materials. In this work, a modified flow-induced crystallization method was employed to fabricate a pure shish-kebab membrane, whose wetting behavior and other related performances were comprehensively studied. The membrane surface displays superhydrophobic characteristic with a static water contact angle of 161° and sliding angle of 3°. More importantly, the superhydrophobic membrane not only is of low adhesive, anti-impact, and self-cleaning performance, but also presents oil/water separation capacity, high absorption capacity with porosity (67–83%), and recyclability for organic liquids. This work proposed a new approach from the viewpoint...

Mimicking the superwetting behaviors of nature creatures is advantageous for the development of multifunctional surfaces. Superhydrophobic surfaces are desired for applications such as self-cleaning, drag reduction, anti-staining, anti-corrosion, oil-water separation, etc. Herein, a superefficient approach is proposed to produce a robust ultrahigh molecular weight polyethylene (UHMWPE) coating on various substrates by dripping and drying UHMWPE solutions. The superhydrophobic surfaces can be tuned between Cassie impregnating state and Cassie state, which resembles the “rose petal effect” and “lotus leaf effect”, respectively, by simply adjusting the quenching temperature and the solvent system. UHMWPE/ortho-xylene biphasic solution resulted in a wrinkled morphology with a high-adhesion superhydrophobic surface, while the UHMWPE/ortho-xylene/cyclohexanone triple-phase solution led to a highly porous morphology with a low-adhesion superhydrophobic surface. The micro-nano structured surfaces displayed promising applicability in droplet transportation, selective oil absorption, anti-staining, and self-cleaning. They also possess superior stability and durability against various liquids and mechanical impact. This work provides a highly efficient approach to produce versatile bionic superhydrophobic coatings with tunable superwetting states.