One-Step Ultraviolet Laser-Induced Fluorine-Doped Graphene Achieving Superhydrophobic Properties and Its Application in Deicing

Asymmetric Laser Enabled High-Throughput Manufacturing of Multiform Magnetically Actuated Graphene-Based Robots for Various Water Depths

Achieving large-scale and facile manufacturing for diverse small-scale robots is critical in the field of small-scale robots. At present, conventional manufacturing methods have limitations in terms of efficiency, environmental friendliness, and operability. In particular, it is difficult to facilely process multiform small-scale robots through a single processing technology only. In this work, with the introduction of an asymmetric laser, multiforms of graphene, including powders, helical, and sheet, were successfully fabricated by simply adjusting laser processing parameters only. This allowed the development of multiform graphene-based robots capable of being actuated in various water depths, including underwater swarm, suspended helical, and floated sheet robots. Importantly, such robots can move smoothly in various trajectories under magnetic fields, including simple geometrical shapes and complicated words, demonstrating good maneuverability. Moreover, this manufacturing method enables the efficient production of multiform robots in different sizes, from 5 to 48 units, within 1 min. The proposed asymmetric laser technology is possible to provide a new means for manufacturing high-performance small-scale robots at high throughput.

Rapidly one-step fabrication of durable superhydrophobic graphene surface with high temperature resistance and self-clean

High temperature resistant and self-cleaning superhydrophobic flexible film has potential application value in lunar exploration. In this paper, a novel method of magnetic field-assisted ultrafast laser induced plasma was proposed to fabricate strongly superhydrophobic graphene on polyimide film with multi-level micro-nano structure. The longitudinal magnetic field contributed to constrain the induced plasma in the lateral direction so as to form a plasma plume with high temperature and high energy density. The multi-level micro-nano graphene structures with better ordering and superhydrophobicity were fabricated, which had a contact angle of 163.1° and a roll-off angle of 1.5°, as well as hydrophobic CC bond content of 72.82 %. The droplets can achieve obvious bouncing at different heights of 1 cm and 5 cm on surfaces at different angles of 0°, 5° and 10°. The contact angle was still greater than 160° after 25 days of aging treatment and heating at 300 °C for 40 min. The water droplets before and after the heating of the sample can push the dust off the surface, showing excellent high temperature resistance and self-cleaning performance.

Dual-Sided Superhydrophobic Laser-Induced Graphene Evaporator for Efficient Desalination and Brine Treatment under High Salinity

The immense energy footprint of desalination and brine treatment is a barrier to a green economy. Interfacial evaporation (IE) offers a sustainable approach to water purification by efficient energy conversion. However, conventional evaporators are susceptible to fluctuations in solar radiation and the salinity of handling liquid. The present research is an innovative step toward the fabrication of superhydrophobic laser-induced graphene (LIG) interfacial evaporators for desalination and brine treatment. The fabricated dual-sided superhydrophobic laser-induced graphene (DSLIG) exhibits self-cleaning ability on both sides, enhancing salt rejection capabilities through a lotus effect. This multilayered evaporator comprises a top layer of MPES LIG and a bottom layer of PVDF AR 972 LIG, resulting in superior localized heat generation ability. The engineered surface has undergone performance analysis with DI water and NaCl solutions with concentrations of 3.5-24 wt %. The dual-stacked configuration with coupled solar (one sun)-joule heating (5 V) attained evaporation rates of ∼5 kg m-2 h-1 for distilled water and ∼2.2 kg m-2 h-1 for a 24 wt % NaCl solution. The remarkable outcome resulted from substantial thermophysical property changes with LIG formation. The DSLIG's bottom concentration gradient promoted salt back diffusion and ceased salt penetration to the top surface. The work can be further extended to treat the desalination brine for sustainable desalination and zero liquid discharge.

Only-sp2 nanocarbon superhydrophobic materials - Synthesis and mechanisms of high-performance

Superhydrophobic systems have fascinated the human kind since the earliest observations of the repellence of water droplets by biological systems. Currently, superhydrophobic materials (SHMs), often inspired by nature and engineered as thin coatings, become an important class of complex systems with numerous industrial implementations. The most important applications of SHMs cover waterproof, self-cleaning, anti-/deicing, anti-fogging, and catalytic systems/units, e.g., in textiles, civil and military engineering, automotive and space industry, and water-from-oil separating systems. In a few above areas, SHMs proved also to be tailorable as smart, i.e., reversibly stimuli-responsive and/or recyclable solutions. In all of those emerging fields, carbon - as the 'sixth element' - represents one of the most prospective components, also in the 'only‑carbon'-based systems. The versatility of carbon (nano)materials, supported by their surface and morphology/topology tunability at from the nano- to macroscale, is vital in the manufacturing of high-performance SHMs. Here, we review only-sp2-hybridized nanocarbon SHMs, i.e., materials exhibiting water contact angle (WCA) >150°, from molecular design to synthesis and evaluation of their application-oriented properties, including WCA. The nanocarbons - pristine/as-made, (non-)covalently functionalized and in a form of carbon‑carbon composites - are analyzed according to their dimensionality: 0D fullerenes, 1D carbon nanotubes (CNTs), 2D graphene, and 3D carbon nanofibers (CNFs). Importantly, this review intends to provide premises toward novel sp2-nanocarbon SHMs, indicating nanowettability and Hansen Solubility Parameters the key ones.

Laser-Induced Graphene-Based Sensors in Health Monitoring: Progress, Sensing Mechanisms, and Applications

The rising global population and improved living standards have led to an alarming increase in non-communicable diseases, notably cardiovascular and chronic respiratory diseases, posing a severe threat to human health. Wearable sensing devices, utilizing micro-sensing technology for real-time monitoring, have emerged as promising tools for disease prevention. Among various sensing platforms, graphene-based sensors have shown exceptional performance in the field of micro-sensing. Laser-induced graphene (LIG) technology, a cost-effective and facile method for graphene preparation, has gained particular attention. By converting polymer films directly into patterned graphene materials at ambient temperature and pressure, LIG offers a convenient and environmentally friendly alternative to traditional methods, opening up innovative possibilities for electronic device fabrication. Integrating LIG-based sensors into health monitoring systems holds the potential to revolutionize health management. To commemorate the tenth anniversary of the discovery of LIG, this work provides a comprehensive overview of LIG's evolution and the progress of LIG-based sensors. Delving into the diverse sensing mechanisms of LIG-based sensors, recent research advances in the domain of health monitoring are explored. Furthermore, the opportunities and challenges associated with LIG-based sensors in health monitoring are briefly discussed.

Advances in Graphene-Based Electrode for Triboelectric Nanogenerator

With the continuous development of wearable electronics, wireless sensor networks and other micro-electronic devices, there is an increasingly urgent need for miniature, flexible and efficient nanopower generation technology. Triboelectric nanogenerator (TENG) technology can convert small mechanical energy into electricity, which is expected to address this problem. As the core component of TENG, the choice of electrode materials significantly affects its performance. Traditional metal electrode materials often suffer from problems such as durability, which limits the further application of TENG. Graphene, as a novel electrode material, shows excellent prospects for application in TENG owing to its unique structure and excellent electrical properties. This review systematically summarizes the recent research progress and application prospects of TENGs based on graphene electrodes. Various precision processing methods of graphene electrodes are introduced, and the applications of graphene electrode-based TENGs in various scenarios as well as the enhancement of graphene electrodes for TENG performance are discussed. In addition, the future development of graphene electrode-based TENGs is also prospectively discussed, aiming to promote the continuous advancement of graphene electrode-based TENGs.

Ultra-Wide Interlayered WxMo2xSy Alloy Electrode Patterning through High-Precision Controllable Photonic-Synthesis

Ultra-thin 2D materials have great potential as electrodes for micro-supercapacitors (MSCs) because of their facile ion transport channels. Here, a high-precision controllable photonic-synthesis strategy that provided 1 inch wafer-scale ultra-thin film arrays of alloyed WxMo2xSy with sulfur vacancies and expanded interlayer (13.2 Å, twice of 2H MoS2) is reported. This strategy regulates the nucleation and growth of transition metal dichalcogenides (TMDs) on the picosecond or even femtosecond scale, which induces Mo-W alloying, interlayer expansion, and sulfur loss. Therefore, the diffusion barrier of WxMo2xSy is reduced, with charge transfer and ion diffusion enhancing. The as-prepared symmetric MSCs with the size of 100 × 100 µm2 achieve ultrahigh specific capacitance (242.57 mF cm-2 and 242567.83 F cm-3), and energy density (21.56 Wh cm-3 with power density of 485.13 W cm3). The established synthesis strategy fits numerous materials, which provides a universal method for the flexible synthesis of electrodes in microenergy devices.

Highly Stable, Bending-Tolerant, and Sustainable Flexible Heater through a Scalable Papermaking Procedure

Flexible electrothermal heaters have attracted abundant attention in recent years due to their wide applications, but their preparation with high efficiency remains a challenge. Here in this work, a highly stable and bending-tolerant flexible heater was fabricated with graphite nanosheets and cellulose fibers through a scalable papermaking procedure. Its electrothermal property can be enhanced by a hot-pressing treatment and introduction of cationic polyacrylamide (CPAM) during the papermaking protocol. The flexible heater may quickly reach its maximum temperature of 239.8 °C in around 1 min at a voltage of 9 V. The power density was up to 375.3 °C cm2 w-1. It appeared to have a high tolerance for bending deformation with various curvatures, and the temperature remained stable even under 100 bending with frequency of around 0.17 Hz. Over 100 alternatively heating and cooling cycles, it worked stably as well. It was proved to be used as wearable heating equipment, soft heaters, and aircraft deicing devices, suggesting its great prospect in the field of heat management.

Laser-Scribed Graphene for Human Health Monitoring: From Biophysical Sensing to Biochemical Sensing

Laser-scribed graphene (LSG), a classic three-dimensional porous carbon nanomaterial, is directly fabricated by laser irradiation of substrate materials. Benefiting from its excellent electrical and mechanical properties, along with flexible and simple preparation process, LSG has played a significant role in the field of flexible sensors. This review provides an overview of the critical factors in fabrication, and methods for enhancing the functionality of LSG. It also highlights progress and trends in LSG-based sensors for monitoring physiological indicators, with an emphasis on device fabrication, signal transduction, and sensing characteristics. Finally, we offer insights into the current challenges and future prospects of LSG-based sensors for health monitoring and disease diagnosis.

Preparation and Anti-Icing Properties of Zirconia Superhydrophobic Coating

Zirconia (ZrO2) is a ceramic material with high-temperature resistance and good insulating properties. Herein, for the first time, the surface of ZrO2 was modified with docosanoic acid (DCA) to improve its self-cleaning and hydrophobic properties. This surface modification transformed the surface of ZrO2 from hydrophilic to superhydrophobic. A two-step spraying method was used to prepare the superhydrophobic surface of ZrO2 by sequentially applying a primer and a topcoat. The primer was a solution configured using an epoxy resin as the adhesive and polyamide as the curing agent, while the topcoat was a modified ZrO2 solution. The superhydrophobic surface of ZrO2 exhibited a contact angle of 154° and a sliding angle of 4°. Scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and other analytical techniques were used to characterize the prepared zirconia particles and their surfaces. Moreover, results from surface self-cleaning and droplet freezing tests showed that DCA-modified ZrO2 can be well combined, and its coatings show good self-cleaning and anti-icing properties on TA2 bases.

Advances in superhydrophobic material research: from preparation to electrified railway protection

Freezing is a serious problem that affects the power, transport, and transmission industries and is a major concern for the national economy and safety. Currently, several engineering de-icing methods, such as thermal, mechanical, and chemical de-icing, have shown problems related to energy consumption, efficiency, and the environment. Superhydrophobic materials have high droplet contact and roll angles, which can reduce the droplet residence and ice adhesion on their surfaces and have unique advantages in the self-cleaning and anti-icing fields. This paper introduces the development of infiltration theory and superhydrophobic materials and their principles of anti-icing and de-icing. Herein, the preparation and coating methods of superhydrophobic materials in applications are summarised, the performance and lifetime issues of superhydrophobic materials in applications are clarified, and the research progress on superhydrophobic materials in different fields is reviewed. Prospects for the application of superhydrophobic materials in electrified railways are also presented. A feasibility study was conducted to solve some of the existing problems of electrified railways, providing a theoretical basis for the development of electrified railways.

Synergistic Effect of Hybrid CdSe Nanobelt/PbI2 Flake Heterojunction Toward Drastic Performance Flexible Photodetectors

Despite numerous studies on broadband photodetectors, the problematic query that remains unaddressed is the limited photoresponsivity while broadening the spectral regime. Here, for the first time, a rational design of a hybrid 1D CdSe nanobelt/2D PbI₂ flake heterojunction device is constructed, which substantially boosts the photocurrent while significantly attenuating the dark current, resulting in improved photodetector figures-of-merit. Thanks to the excellent quality of the nanobelt/flake and built-in electric field at the CdSe/PbI₂ interface heterojunction, photogenerated carriers are promptly segregated and more photoexcitons are accumulated by the respective electrodes, enabling a high responsivity of ∼10⁶ A/W, making this one of the highest values among similar reported hybrid heterojunction photodetectors, together with a large linear dynamic range, superior sensitivity, excellent detectivity and external quantum efficiency, an ultrafast response, and a broadband spectral response range. The similar 1D/2D hybrid heterojunction device architecture assembled on the flexible polyimide tape substrate exhibits excellent folding endurance and mechanical, flexural, and long-term environmental stability. The present device architecture and robust operational stability in an ambient environment reveals that the combination of the present 1D/2D hybrid heterojunction has incredible potential for future flexible photoelectronic devices.

Synthesis of bentonite/Ag nanocomposite by laser ablation in air and its application in remediation

In this research, a simple, green, and efficient approach is described to produce novel bentonite/Ag nanocomposite wherein the preparation of Ag nanoparticles (Ag NPs) deployed the laser ablation method in air; Ag NPs are deposited on the bentonite via the magnetic stirring method. The structural and morphological characterization of the as-prepared bentonite/Ag nanocomposite (denoted as B/Ag30, 30 min being the laser ablation time) is accomplished using different methods. Additionally, the catalytic assessment of the ensued composite exhibited excellent catalytic reduction/degradation activity for common aqueous pollutants namely methyl orange (MO), congo red (CR) and 4-nitrophenol (4-NP) utilizing NaBH₄ as reductant. Furthermore, the recycling tests displayed the high stability/reusability of B/Ag30 nanocomposite for at least 4 runs with retention of catalytic prowess.

A review: studying the effect of graphene nanoparticles on mechanical, physical and thermal properties of polylactic acid polymer

Polylactic acid (PLA) is a linear aliphatic polyester thermoplastic made from renewable sources such as sugar beet and cornstarch. Methods of preparation of polylactic acid are biological and chemical. The advantages of polylactic acid are biocompatibility, easily processing, low energy loss, transparency, high strength, resistance to water and fat penetration and low consumption of carbon dioxide during production. However, polylactic acid has disadvantages such as hydrophobicity, fragility at room temperature, low thermal resistance, slow degradation rate, permeability to gases, lack of active groups and chemical neutrality. To overcome the limitations of PLA, such as low thermal stability and inability to absorb gases, nanoparticles such as graphene are added to improve its properties. Extensive research has been done on the introduction of graphene nanoparticles in PLA, and all of these studies have been studied. In this study, we intend to study a comprehensive study of the effect of graphene nanoparticles on the mechanical, thermal, structural and rheological properties of PLA/Gr nanocomposites and also the effect of UV rays on the mechanical properties of PLA/Gr nanocomposites.

Biogenic synthesis of reduced graphene oxide decorated with silver nanoparticles (rGO/Ag NPs) using table olive (olea europaea) for efficient and rapid catalytic reduction of organic pollutants

In this work, graphene oxide (GO) sheets were prepared via a facile electrochemical exfoliation of graphite in acidic medium and subsequent oxidation with potassium permanganate. The GO sheets were employed for preparation of reduced GO adorned with nanosized silver (rGO/Ag NPs) using green reduction of GO and Ag(I) via olive fruit extract as a reducing and immobilizing agent. The crystal phase, morphology, and nanostructure of the prepared catalyst were characterized by XRD, SEM, EDX, UV-Vis and Raman spectroscopy techniques. The as-prepared rGO/Ag NPs showed superior catalytic performance towards the complete reduction (up to 99%) of 4-nitrophenol (4-NPH) to 4-aminophenol (4-APH) and rhodamine B (RhB) to Leuco RhB within 180 s using NaBH₄ at ambient condition. The rate constant (k) values were found to be 0.021 and 0.022 s^-1 for 4-NPH and RhB reduction, respectively. In addition, the regenerated catalyst could be reused after seven cycles without losing any apparent catalytic efficiency. Accounting for the excellent catalytic capability, chemical stability and environment-friendly synthesis protocol, the rGO/Ag NPs has great potential working as a heterogeneous catalyst in the transforming harmful organic contaminants into less harmful or harmless compounds.

Fabrication of Durable, Chemically Stable, Self-Healing Superhydrophobic Fabrics Utilizing Gellable Fluorinated Block Copolymer for Multifunctional Applications

Limited durability and complex materials restrict the application of superhydrophobic fabrics in daily life. In this work, gellable fluorinated block copolymer poly(dodecafluoroheptyl methacrylate)-block-poly(3-(triethoxysilyl)propyl methacrylate) (PDFMA-b-PTEPM) was used to fabricate adhesive-free superhydrophobic poly(ethylene terephthalate) (PET) fabrics via a simple dip-coating technology and sol-gel reaction. The growth of silica nanoparticles builds up a rough hierarchical structure and provides sol-gel reaction sites of PTEPM segments. The grafting of block copolymer significantly reduced the surface free energy of the fabrics, resulting in an excellent superhydrophobicity with a water contact angle of 160.2°. Benefiting from extensive chemical bond grafting and cross-linking of the PTEPM segment, the fabric exhibits excellent durability in mechanical abrasion, chemical treatment, and washing. The coating has withstood 50 sandpaper abrasion cycles and 400 soft friction cycles and can maintain superhydrophobic properties in various solvents, freezing and a wide pH range. These superhydrophobic fabrics with a long life span possess self-cleaning, anti-icing, oil-water separation, and self-healing capabilities. The multifunctional fabrics developed in this study are durable and easy to produce, possessing the potential for applications in industry and daily life.

Effect of Graphene Oxide on the Properties of Polymer Inclusion Membranes for Gold Extraction from Acidic Solution

The cyanidation leaching method is hazardous to the environment, but it is widely applied in the gold mining process because it is effective for gold extraction. This study fabricates polymer inclusion membranes (PIMs), which have environment-friendly properties, with graphene oxide (GO) as an alternative to the cyanidation leaching method for gold extraction. Poly(vinylidenefluoride-co-hexa-fluoropropylene)-based PIMs with different GO concentrations in five membranes (i.e., M1 (0 wt.%), M2 (0.5 wt.%), M3 (1.0 wt.%), M4 (1.5 wt.%), and M5 (2.0 wt.%)) are studied for their potential to extract gold from a hydrochloric acid solution. The membranes are prepared using di-(2-ethylhexyl) phosphoric acid as the extractant and dioctyl phthalate as the plasticizer. Scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, ion exchange capacity, and water uptake are used to characterize the physical and chemical properties of the fabricated PIMs. The results show that the optimized membrane for gold extraction is M4 (1.5 wt.% GO), which yields a better performance on thermal stability, ion exchange capacity (IEC), and water uptake. M4 (1.5 wt.% GO) also exhibits a smooth and dense structure, with the maximum extraction efficiency obtained at 84.71% of extracted gold. In conclusion, PIMs can be used as an alternative for extracting gold with a better performance by the presence of 1.5 wt.% GO in membrane composition.

Exfoliation of MoS2 Quantum Dots: Recent Progress and Challenges

Although, quantum dots (QDs) of two-dimensional (2D) molybdenum disulfide (MoS2) have shown great potential for various applications, such as sensing, catalysis, energy storage, and electronics. However, the lack of a simple, scalable, and inexpensive fabrication method for QDs is still a challenge. To overcome this challenge, a lot of attention has been given to the fabrication of QDs, and several fabrication strategies have been established. These exfoliation processes are mainly divided into two categories, the 'top-down' and 'bottom-up' methods. In this review, we have discussed different top-down exfoliation methods used for the fabrication of MoS2 QDs and the advantages and limitations of these methods. A detailed description of the various properties of QDs is also presented.

Wettability Controlled Surface for Energy Conversion

To achieve clean and high-efficiency utilization of renewable energy, functional surfaces with controllable and patternable wettability are becoming a fast-growing research focus. In this work, a laser scribing strategy to fabricate patterned graphene surfaces that are capable of energy conversion in different forms is demonstrated. Using the laser raster-scanning and vector-scanning modes, two distinct surface structures are constructed on polybenzoxazine substrate, yielding a superhydrophilic (LSHL) surface and superhydrophobic (LSHB) surface, respectively. Of particular note is that the unique hierarchical structure of LSHB surface has endowed it with quite a robust superwetting behaviors. Further profiting from the flexibility of the processing method, wettability patterns with spatially resolved LSHL and LSHB regions are designed, achieving the conversion of surface energy to liquid kinetic energy. This also offers a tractable approach to fabricate wettability-engineered devices that enable the directional, pumpless transport of water by capillary pressure gradient and the selective surface cooling via jet impingement. In addition, the LSHB surface demonstrates the high conversion of electric-to-thermal energy (222 °C cm² W^-1 ) and light-to-thermal energy (88%). Overall, the material system and processing method present a promising step forward to developing easy-fabricated graphene surfaces with spatially controlled wettability for efficient energy utilization and conversion.

Laser Processing of Flexible In-Plane Micro-supercapacitors: Progresses in Advanced Manufacturing of Nanostructured Electrodes

Flexible in-plane architecture micro-supercapacitors (MSCs) are competitive candidates for on-chip miniature energy storage applications owing to their light weight, small size, high flexibility, as well as the advantages of short charging time, high power density, and long cycle life. However, tedious and time-consuming processes are required for the manufacturing of high-resolution interdigital electrodes using conventional approaches. In contrast, the laser processing technique enables high-efficiency high-precision patterning and advanced manufacturing of nanostructured electrodes. In this review, the recent advances in laser manufacturing and patterning of nanostructured electrodes for applications in flexible in-plane MSCs are comprehensively summarized. Various laser processing techniques for the synthesis, modification, and processing of interdigital electrode materials, including laser pyrolysis, reduction, oxidation, growth, activation, sintering, doping, and ablation, are discussed. In particular, some special features and merits of laser processing techniques are highlighted, including the impacts of laser types and parameters on manufacturing electrodes with desired morphologies/structures and their applications on the formation of high-quality nanoshaped graphene, the selective deposition of nanostructured materials, the controllable nanopore etching and heteroatom doping, and the efficient sintering of nanometal products. Finally, the current challenges and prospects associated with the laser processing of in-plane MSCs are also discussed. This review will provide a useful guidance for the advanced manufacturing of nanostructured electrodes in flexible in-plane energy storage devices and beyond.

Research Progress on the Preparation and Applications of Laser-Induced Graphene Technology

Graphene has been regarded as a potential application material in the field of new energy conversion and storage because of its unique two-dimensional structure and excellent physical and chemical properties. However, traditional graphene preparation methods are complicated in-process and difficult to form patterned structures. In recent years, laser-induced graphene (LIG) technology has received a large amount of attention from scholars and has a wide range of applications in supercapacitors, batteries, sensors, air filters, water treatment, etc. In this paper, we summarized a variety of preparation methods for graphene. The effects of laser processing parameters, laser type, precursor materials, and process atmosphere on the properties of the prepared LIG were reviewed. Then, two strategies for large-scale production of LIG were briefly described. We also discussed the wide applications of LIG in the fields of signal sensing, environmental protection, and energy storage. Finally, we briefly outlined the future trends of this research direction.