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Photothermal superhydrophobic surfaces have been demonstrated for anti-icing/deicing applications. However, preparing these materials using simple and environmentally friendly methods remains a challenge. Herein, a high-efficiency energy utilization strategy based on a photothermal-wind synergistic effect combined with superhydrophobicity has been proposed for anti-icing/deicing. Using onestep femtosecond laser direct writing technology, we modified a polyether ether ketone surface, which resulted in a superhydrophobic surface with photothermal effects. The optimized fabrication condition was laser treatment with velocity of 80 mm s−1 (LT-V80), which gave a surface possessing a high water contact angle (∼160.9°) and a low rolling angle (∼3°), and excellent self-cleaning properties were seen. Furthermore, LT-V80 showed high light absorptivity (∼94.6%), which caused the surface temperature to increase by 44.5 °C under 1.0 sun illumination. The addition of wind to the system resulted in a synergistic effect together with the photothermal and superhydrophobic properties, and caused a 87.1% reduction of the deicing time and a 220.3% increase in the icing time. This strategy also demonstrated good deicing efficiency in a cold outdoor environment. An efficient solar energy utilization strategy as demonstrated by LTV80 indicates that efficient anti-icing/deicing is possible using simple, environmentally friendly, and low cost fabrication methods. [ABSTRACT FROM AUTHOR]

Frost formation is a normal phase transition phenomenon in cold climates, while it usually brings certain troubles to human lives and production. Therefore, it is of great significance to develop frost resistant materials and key technologies. Here, a salt-philic and superhydrophobic surface is designed on a PDMS substrate by femtosecond laser direct writing technology in combination with salt–ethanol–water mixtures droplet treatment. The laser-treated PDMS embedded salt (LTP-S) surface exhibits superhydrophobicity, which alone is a property that can resist the formation of frost and enables a self-cleaning effect. Meanwhile, the salt coating further enhances the frost resistance of the surface by reducing the freezing point temperature. The LTP-S surface is revealed to perform well in frosting-defrosting cycles, washing resistance, chemical corrosion resistance, heating resistance, and long-term air exposure tests as a highly efficient and stable anti-frosting surface. This work demonstrates a facile strategy to fabricate a salt-philic and superhydrophobic surface for efficient anti-frosting. [ABSTRACT FROM AUTHOR]

Liquid droplets on superheated surfaces produce the Leidenfrost effect. This phenomenon might lead to droplet manipulation and control strategies in microfluidics and thermal management. However, Leidenfrost droplets move randomly and irregularly on superheated surfaces and the manufacturing of special surfaces to control Leidenfrost droplet movement poses great challenges. Here, we propose a simple and environment-friendly method to create heterogeneously wetting surface structures to control the spin motion of droplets on superheated brass using femtosecond laser patterning. The water contact angle of the superhydrophobic area on the surface was ∼160°, and the superhydrophilic area showed ∼7°. A z-shaped pattern was fabricated, which segmented the vapor film and influenced gas flow, and it resulted in the spinning of oval-shaped droplets analogous to a spinning egg. We used simulation to explain this phenomenon and also expanded the application of this droplet control in accelerating dissolution of solids and mechanical driving. This study provides the basis for a creative control method using the Leidenfrost droplet phenomenon, which has broad implications in steam-driven droplet motion and future fluid manipulation. [ABSTRACT FROM AUTHOR]

Crystalline and porous metal–organic frameworks (MOFs) are potential candidates for different antibacterial, photocatalytic, and adsorption applications. Moreover, multiprincipal element nanoparticles are effective against multidrug‐resistant bacteria, and combining metals with carbon nanomaterials can enhance activity. Herein, a Tri‐MOF comprised of iron, zinc, cobalt and 2‐methyl imidazole is grown together with laser‐induced graphene (LIG) powder. Electron microscopy imaging shows the successful preparation and the crystalline nature of the LIG/Tri‐MOF composite. Fourier‐transform infrared and X‐Ray photoelectron spectroscopy confirm a noncovalent mixture of LIG and Tri‐MOF. Compared with the negligible activity of LIG alone, low doses (0.91–4.54 mg mL−1) of the prepared LIG/Tri‐MOF composite show excellent antibacterial activity (≥95% bacterial removal) and a MIC of 0.6 mg mL−1 for Gram‐negative bacteria, via the gradual leaching of metal ions and organic linker from the material enhanced by bacterial aggregation near the LIG/Tri‐MOF. Compared to a mixture of separately synthesized Tri‐MOF and LIG, the LIG/Tri‐MOF composite shows improved antibacterial effects. All materials show cytotoxicity for L929 mouse cell lines, the solids showing a disrupting effect on cells grown in vitro. Performance‐enhancing combinations of various materials leading to synergistic or additive antimicrobial effects are essential strategies for minimizing the possible emergence of antibiotic‐resistant strains. [ABSTRACT FROM AUTHOR]

Marine oil spills have become a major global environmental challenge, yet there remains a lack of effective and environmentally friendly strategies for the remediation of water contaminated with high-viscosity oil. In this study, we introduce a superhydrophobic oleophilic material with photothermal properties for efficient absorption of viscous oil. Femtosecond laser treatment methodology is applied to cork (FSLA-cork), which exhibits not only superior hydrophobic and oleophilic properties but also the exceptional ability to be rapidly heated from ambient conditions to 58 °C in 10 s under 1.8 solar irradiation. Under solar irradiance, the FSLA-cork adsorbent functions synergistically by capillary absorption and centrifugal pumping. At one-sun intensity, an oil absorption rate of 4.02 g cm−2 within 200 s was observed. The high adsorption rates of FSLA-cork combined with the high availability of the raw material and its eco-friendly fabrication methods indicate that such methods and materials can be utilized for large-scale clean up of aqueous environments contaminated with high-viscosity oils. [ABSTRACT FROM AUTHOR]

Modulating the thermal emission of a material in the infrared (IR) range can be essential for various practical applications such as smart textiles, camouflage, and anti-counterfeiting. Although many different materials or structures have been proposed, the complex manufacturing processes are still hindering their widespread use. Herein, a facile femtosecond laser processing technology and a drop-coating method are introduced to form a patternable low emissivity film. Laser-treated polyimide films resulted in superhydrophilic structured surfaces that are uniformly coated with silver-nanowires (AgNWs) in aqueous solutions for low emissivity surfaces. Furthermore, the emissivity of the samples is as low as ∼0.2 without deterioration over 800 bending-releasing cycles. The as-prepared films also display good thermal camouflage properties, namely, the films reduced the thermal radiation temperature of an object by 35.8 °C when the object temperature was ∼69.1 °C. Additionally, this IR camouflage effect of the AgNWs coated samples shows excellent stability even in harsh environments such as immersion in water, acid, alkali, and salt solution and applied voltage. We also show that information encryption was possible by adjusting the amount of AgNWs. The design of this programmable patterned low emissivity film indicates an idea for the thermal camouflage and anti-counterfeiting technology, which can carry more abundant application scenario and disguise them more complex and sophisticated. [ABSTRACT FROM AUTHOR]

Numerous treatment methods such as biological digestion, chemical oxidation, and coagulation have been used to treat organic micropollutants. However, such wastewater treatment methods can be either inefficient, expensive, or environmentally unsound. Here, we embedded TiO2 nanoparticles in laser-induced graphene (LIG) and obtained a highly efficient photocatalyst composite with pollutant adsorption properties. TiO2 was added to LIG and lased to form a mixture of rutile and anatase TiO2 with a decreased band gap (2.90 ± 0.06 eV). The LIG/TiO2 composite adsorption and photodegradation properties were tested in solutions of a model pollutant, methyl orange (MO), and compared to the individual and mixed components. The adsorption capacity of the LIG/TiO2 composite was 92 mg/g using 80 mg/L MO, and together the adsorption and photocatalytic degradation resulted in 92.8% MO removal in 10 min. Adsorption enhanced photodegradation, and a synergy factor of 2.57 was seen. Understanding how LIG can modify metal oxide catalysts and how adsorption can enhance photocatalysis might lead to more effective pollutant removal and offer alternative treatment methods for polluted water. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces are capable to resist the adhesion of organisms through a surface bound air layer, known as a plastron. However, the lifetime of such plastrons is limited and their decay results in the loss of the protective barrier against organism attachment. Here a method is established to replenish the plastron by Joule heating of electrically conductive, superhydrophobic laser‐induced graphene (SLIG) coatings. Local heating with a DC current reduces the water solubility of gases and the growth of an initial microplastron into a macroplastron through gas nucleation at the liquid–air interface is observed. Small temperature differences between the surface and the surrounding water could induce this effect. Different SLIG surfaces are challenged against biofouling by the diatom Navicula perminuta under dynamic conditions and it is shown that surfaces with intact plastron resist diatom accumulation. Surfaces without the protective air layer are found to accumulate high amounts of diatoms. The results underline the promising potential of plastron‐based antifouling approaches because plastrons can be stabilized for extended times. This strategy could be applied to many other materials for an effective protection against fouling organism. [ABSTRACT FROM AUTHOR]

Biofouling is an ongoing challenge for water treatment membrane processes. Reducing biofilm growth on the membrane surface or on the polymeric feed spacer will reduce operation, maintenance, and module replacement costs. Laser‐induced graphene (LIG) is a low cost, environmentally friendly, electrically conductive carbon material shown to have antibiofouling properties. Here it has been shown that an electrically conductive LIG‐coated polypropylene (PP) feed spacer has both antimicrobial and antifouling effects under a low electrical current, and when implemented into a spiral wound membrane module reduced biofilm growth on both the membrane and the spacer components. The antibacterial property of the LIG spacer is tested using Pseudomonas aeruginosa and the brackish water Rheinheimera sp. as model organisms. Using a voltage of 12 V, P. aeruginosa is completely inactivated in 10 h, while a dynamic accumulation assay employing Rheinheimera sp. showed significant reduction (p < 0.05) in bacterial adhesion compared to an uncoated spacer. The spacer is incorporated into a spiral wound reverse osmosis (RO) membrane module, and reduced biofouling is observed on both the membrane and LIG spacers components using brackish water and 12 V. This study demonstrates the feasibility of electrically conductive feed spacer components in spiral wound RO membrane modules. [ABSTRACT FROM AUTHOR]

Biofouling on surfaces in contact with sea- or brackish water can severely impact the function of devices like reverse osmosis modules. Single species laboratory assays are frequently used to test new low fouling materials. The choice of bacterial strain is guided by the natural population present in the application of interest and decides on the predictive power of the results. In this work, the analysis of the bacterial community present in brackish water from Mashabei Sadeh, Israel was performed and Rheinheimera sp. was detected as a prominent microorganism. A Rheinheimera strain was selected to establish a short-term accumulation assay to probe initial bacterial attachment as well as biofilm growth to determine the biofilm-inhibiting properties of coatings. Both assays were applied to model coatings, and technically relevant polymers including laser-induced graphene. This strategy might be applied to other water sources to better predict the fouling propensity of new coatings. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is a method of generating a foam-like conformal carbon layer of porous graphene on many types of carbon-based surfaces. This electrically conductive material has been shown to be useful in many applications (e.g., environmental technology) and exhibits low fouling and antimicrobial surfaces. Moreover, polymers and concrete composite materials have been made. Since LIG is formed using common engraving or cutting lasers, LIG images on paper products was recently termed "graphene art". Here we show that graphene art generated on polymers can be composited and made functional. Pouring concrete on LIG images obtained on poly-(ether sulfone) or polyimide and transferring the LIG onto the set concrete surface by simply peeling off the polymer support resulted in LIG-concrete composite artistic designs. The electrically conductive LIG-concrete composite art was functional and showed antibacterial effects when an electrical potential was applied (i.e., an antimicrobial rate (AR) of 100%a 5 log reduction). These examples show that artistically designed LIG-concrete composites can be functional by utilizing the electrical and chemical properties of LIG and especially for antibacterial effects, which might be of use for incorporation into structural aspects of hospitals or other buildings where sterile surfaces might provide added protection for immune-compromised patients. [ABSTRACT FROM AUTHOR]

A hybrid antibiotic consisting of vancomycin and nisin fragments is more active than the separate fragments against vancomycin resistant enterococci (VRE). Three different hybrids are prepared by using click chemistry and optimal spacer lengths and connection points are predicted by using computer modeling.

Several multivalent-made antimicrobial peptide magainin 2 compounds are examined for their pore-forming capability in large unilamillar vesicles (LUVs). Results show an almost 600-fold enhancement in pore formation by these compounds.

Previously, laser-induced graphene (LIG) coated surfaces were shown to resist biofilm growth, although the material was not strongly antibacterial. Here, we show LIG surfaces doped with silver nanoparticles (Ag0 or AgNPs) as highly antibacterial surfaces. Starting from AgNO3 polyethersulfone (PES) polymer substrates, silver nanoparticles between 5–10 nm were generated in situ during the lasing process and stably embedded in the fibrous and porous structure of LIG in a single step. These silver doped LIG (Ag@LIG) surfaces were highly toxic to bacteria via a mechanism of both Ag+ ion release and possible surface toxicity of the AgNPs. The added antibacterial function of Ag-nanoparticles expands the functionality of LIG coated surfaces and might lead to highly effective point of use/entry devices in rural areas or in disaster situations with contaminated water sources. [ABSTRACT FROM AUTHOR]