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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]

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]

Laser-induced graphene (LIG) is a graphitic material that can be easily formed by CO 2 -laser irradiation on a variety of carbon-based substrates, including porous polymeric membranes. LIG-membrane formation involves lasing the top surface of a polymeric membrane, and converts essential polymer separation structures to porous LIG foam. However, in previous studies, separation properties could be partly recovered by forming LIG polymer composite layers or by coating the polymeric membrane substrate with trimethylaluminum (TMA) or graphene oxide (GO) to avoid melting or damaging the membrane pore structure and the subsurface polymeric structures during the lasing process. Herein, by optimizing the laser settings and fabrication conditions, we made LIG directly on uncoated porous PES membranes, while preserving the subsurface polymer. The effects of lasing on membrane properties were studied by comparing porous polymeric PES membranes fabricated using the non-solvent induced phase separation (NIPS) or the vapor-induced phase separation (VIPS) method. Membrane fabrication conditions such as the polymer concentration of the casting solution and the exposure time to the non-solvent were varied, and the NIPS method resulted in membranes with a finger-like polymer substructure morphology while the VIPS method resulted in membranes with an asymmetric cellular morphology. LIG-membranes prepared on NIPS membranes resulted in large permeability changes, while LIG on VIPS membranes gave only very minor changes. The antimicrobial activity of these LIG-membranes as porous electrodes was dependent on applied voltage and solution contact time and 4–6 log removal of bacteria at 10 V was achieved. Understanding LIG formation on porous polymeric membranes will minimize processing steps and might lead to electrically conductive membranes with controlled separation properties. [Display omitted] • Laser-induced graphene (LIG) was optimized on different membrane structure types. • Uncoated NIPS and VIPS membranes were lased without melting the subsurface polymer. • Increased LIG contact time enhanced electrically dependent antimicrobial activity. • 4–6 log removal of bacteria at 10 V was achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • Laser-induced graphene was generated on PES with different wetting properties. • LIG coatings reduce marine biofilm growth. • Application of electrochemical potentials reduces the attachment of marine bacteria. • Cyclic voltammograms reveal the electrochemical conversions on the LIG surfaces. • At positive potentials, reactive oxygen and chloride species are formed. Biofouling can severely impact the function of devices in contact with sea- or brackish water. Laser-induced graphene (LIG) was previously discovered to resist bacterial attachment and when electrochemically activated to reduce their viability. Here we investigated the suitability of LIG and electrochemically activated LIG to counteract the attachment of marine organisms in high salinity media. We fabricated LIG on poly(ether)sulfone with optimized electrical conductivity and varied the wettability of the surfaces using atmospheric plasma and chemical modification. The superhydrophilic and superhydrophobic LIG surfaces were challenged with the marine bacterium Cobetia marina in a dynamic attachment assay, which showed that superhydrophobic LIG coatings are capable to resist bacteria accumulation. An extended biofilm growth experiment revealed that even unfunctionalized LIG coatings outperformed control gold coated glass surfaces modified with 1-dodecanthiol after 36 h by showing a reduced biofilm coverage. Electrochemical measurements performed under static conditions showed reduction of bacteria accumulation for potentials above +1.4 V. This effect was attributed to the formation of H 2 O 2 , which was detected at µM levels. The results underline the promising potential of LIG surface modification as method to counteract marine fouling. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) is a three-dimensional porous carbon material prepared by direct laser writing with a CO 2 laser on various polymers in an ambient atmosphere, leading to electrically conductive, low fouling coatings. Recently, LIG has been synthesized on porous supports, which led to highly permeable and porous separation filters and LIG composites have greatly improved the stability. On the other hand, graphene oxide (GO) has emerged as a promising 2D nanomaterial to coat porous or non-porous polymer membrane supports resulting in separation membranes with enhanced separation and surface properties. Here, we report a robust, hybrid LIG-GO membrane fabricated by filtration and crosslinking of GO onto the LIG membrane support, generating ultrafiltration membranes with tailored performance. Increasing the amount of crosslinked GO on the LIG surface resulted in increased rejection of bovine serum albumin (BSA) up to 69%, and bacterial rejection was increased from 20 to 99.9%, which agreed with the measured molecular weight cut-off determination that approached ~ 90 kDa as the GO content increased. Higher flux recovery ratios and lower BSA adsorption were seen with LIG-GO membranes, and the hybrid membranes showed comparatively good antifouling. These composite membranes showed 83% less biofilm growth compared to a typical polymer ultrafiltration membrane under non-filtration condition. Noteworthy is that the LIG supporting layer maintained its electrical conductivity and the LIG-GO membrane used as electrodes showed complete elimination of bacterial viability with potent antimicrobial killing effects when treated with mixed bacterial culture. In cross-flow filtration, LIG-GO membranes with 3V anodic electric field showed 11% improvement of flux as compared to typical polymer ultrafiltration membrane. The LIG-GO membranes expand possibilities for the use of LIG in membrane separation applications, especially ultrafiltration. Carbon-based antifouling, electrically conductive ultrafiltration membranes were fabricated using laser-induced graphene membrane supports and crosslinked graphene oxide. Image 1 • laser-induced graphene (LIG) integrated into composite membranes. • LIG composites with crosslinked graphene oxide(GO) show ultrafiltration properties. • LIG-GO composite membranes stable under extended sonication at low and high pH. • Membranes electrically active, showing low fouling and bacterial killing effects. • LIG-GO more biofouling resistant than commercial UF membrane in cross-flow testing. [ABSTRACT FROM AUTHOR]