Dispersion Of Graphene Research Articles

Synthesis of Graphene / Copper Composite Thin Foils As Innovative Anode Current Collectors for Lithium-Ion Batteries

Lithium-ion batteries (LIB) are now considered as standard power storage units in laptops, mobile phones, and electric cars. Yet, they trigger important and constant R&D efforts to improve their energy density, lifespan, safety, and cost efficiency. Among LIB components, anodic copper current collector contributes to 8.1% of the total LIB weight [1]. In their ongoing quest to reduce the thickness of the anodic electrode foils, manufacturers face now a 6 µm thickness limitation due to mechanical issues (wrinkling and tearing) complicating their processing. In this context, using lighter materials with improved mechanical properties (with equal or improved thermal and electrical conductivity) compared to pristine copper is considered as an interesting solution to contribute to a further improvement of Lithium-Ion Batteries energy density.Owing to its high mechanical properties, high electrical and thermal conductivity, and low density [2], graphene and its derivates could be considered as promising materials to fabricate graphene / copper composites and achieve thinner / lighter current collectors. Such composites have already been successfully synthetised using copper electroplating with clear thermal and mechanical improvement [3].The work to be presented in this talk will describe a new and simple route for the fabrication of graphene nanoplatelets (GNPs) or graphene oxide (GO) / copper composites consisting of : (i) the dispersion of graphene derivates in ethanol, (ii) their spraying onto Titanium substrate, (iii) a post electroplating on the sprayed graphene materials. In case of GNPs, a prior functionalization by polydopamine biopolymer is performed to increase their hydrophilicity and allow their dispersion. The polydopamine polymerization mechanism is known in literature to be complex and not extensively understood. The investigations done to understand the functionalization of GNPs by polydopamine using different techniques like Transmission Electron Microscopy (TEM) and X-ray Photoemission Spectroscopy (XPS) will be shared. Moreover, the use of Helium Ions Microscopy coupled with Secondary Ions Mass Spectrometer (HIM-SIMS) has been chosen as an original and powerful technique to further study the conformation of polydopamine onto GNPs. Finally, we will present the fabrication of thin graphene oxide copper composite foils and their characterization using Scanning Electron Microscope (SEM). A special focus will be given on the comprehension of copper nucleation behaviour on Graphene materials that remains not well studied. Electrochemical techniques such as impedance and current transient nucleation and growth analysis is currently under testing.[1] Zhu, P. Gastol, D. Marshall, J. Sommerville, R. Goodship, V. Kendrick, E. J Power Sources, 485, 229321 (2021)[2] Fatemeh Farjadian et al. Recent Developments in Graphene and Graphene Oxide: Properties, Synthesis, and Modifications: A Review 5,10200-10219, Chemistry Europe (2020)[3] Song, G. et al.. One-step synthesis of sandwich-type Cu/graphene/Cu ultrathin foil with enhanced property via electrochemical route. Materials and Design, 191, 108629. (2020)

Self-assembly strengthening-toughening epoxy/Graphene composites through intermolecular π-π interactions with ultralow Graphene content

Dispersion of Graphene (GE), high cost of massive usage of GE, and synergistic efficiency of GE and other fillers on epoxy resin (ER) are still challenges. This work not only achieves the uniform dispersion of few-layered GE through π-π interaction between GE and phenyl glycidyl ether (PGE), but also presents an equation in calculating the synergistic efficiency of multiple tougheners. The results show that the strength, modulus, elongation at break, and impact strength of ER can be simultaneously improved when D8 (an epoxy resin with side aliphatic chains) and PGE/GE are used together (D8/PG-X samples) or alone, and the D8/PG-X samples exhibit incomparable positive synergistic efficiency in both strength and toughness with ultralow GE content. The improvement of the impact strength, elongation at break, tensile modulus, and tensile strength in the optimum D8/PG-5 system is 115.5 %, 45.7 %, 17.8 %, and 28.3 % compared with unmodified ER system. We demonstrate that the improved comprehensive properties of the D8/PG-X samples as well as the improved interlaminar shear strength (ILSS) of the carbon fiber (CF)/ER composites can be ascribed to synergistic strengthening-toughening effect of self-assembly effect of aliphatic chains in D8 and uniformed dispersed GE (by π-π interaction). The impressive synergistic strengthening-toughening strategy can provide theoretical guidance for the preparation of high-performance ER with ultralow GE content.

Electrochemical exfoliation of graphene without drying for direct preparation of Ag/graphene coating

The high production cost and agglomeration of graphene are the primary challenges limiting the large-scale practical application of graphene-enhanced nanocomposites. In this study, graphite rods were electrochemically exfoliated in the nitric acid solution, and the undried exfoliated graphene was directly dispensed into the deposition solution. The esterification reaction of hydroxyl and carboxyl groups was blunted due to the spatial site-barrier effect of water molecules present in graphene. Irreversible agglomeration due to drying in the usual graphene preparation process was avoided, resulting in a composite electroplating solution with uniform graphene dispersion. On this basis, Ag/graphene composite coatings were electrochemically deposited. The graphene in the composite coating was uniformly distributed, and the surface was smooth and free of agglomeration. At the same time, the incorporation of graphene changed the coating grain orientation shift from (220) crystal plane to low-energy (111), (200) crystal plane orientation. The surface energy of the composite coating was dramatically reduced, the hardness was increased, and the wear resistance was significantly improved. This study provides a low-cost and high-quality solution for preparing graphene composites.

Synthesis and characterization of homogeneously dispersed graphene–copper heterostructures with enhanced thermal properties

Synthesis and characterization of homogeneously dispersed graphene–copper heterostructures with enhanced thermal properties

The role of solvent interfacial structural ordering in maintaining stable graphene dispersions

Liquid phase exfoliation is the most promising method for the low-cost, scalable production of two-dimensional nanosheets from their bulk counterparts. Extensive exfoliation occurs in most solvents due to the huge amount of energy introduced by sonication or shear mixing. However, the subsequent dispersion is not always stable, with extensive reaggregation occurring in some solvents. Identifying the optimal solvent for a particular layered material is difficult and requires a fundamental understanding of the mechanism involved in maintaining a stable dispersion. Here, we use molecular dynamics calculations to show that when graphene is immersed in a solvent, distinct solvation layers are formed irrespective of the choice of solvent and their formation is energetically favourable for all considered solvents. However, energetic considerations such as these do not explain the experimental solvent-dependence of the dispersion concentration. Instead, we find that solvents with high diffusion coefficients parallel to the graphene layer result in the lowest experimental concentration of graphene in solution. This can be explained by the enhanced ease of reaggregation in these solvents. Solvents with smaller diffusion coefficients result in higher experimental graphene concentrations as reaggregation is prevented. In the low diffusion limit, however, this relationship breaks down. We suggest that here the concentration of graphene in solution depends primarily on the separation efficiency of the initial exfoliation step. Based on this, we predict that the concentration of exfoliated graphene in solvents such as benzaldehyde and quinoline, which have low diffusion constants, can be increased dramatically by careful tuning of the experimental sonication parameters.

A novel crosstalk-free piezoresistive/self-capacitive bimodal sensor for human-robot collaboration

In practical applications of collaborative robots, proximity and pressure sensing capabilities are crucial for ensuring the safety and effectiveness of interaction. This paper proposes a novel method of integrating a bimodal sensor that uses a piezoresistive membrane as a self-capacitive electrode, overcoming the current challenges in integration and signal independence. By optimizing the graphene dispersion concentration, the prepared piezoresistive membrane can meet the initial resistance requirements of the self-capacitive electrode and the high sensitivity requirements of piezoresistive sensing. Experimental trials conducted to characterize the sensor focus on its sensitivity (8.49 MPa−1 /2.75% cm−1), response time, and repeatability for both pressure and proximity sensing. Results indicate successful dual-mode detection with crosstalk-free between the two sensing modalities, achieved by evaluating proximity performance under different pressure conditions. Furthermore, a practical application of a 6-array e-skin mounted on a robotic arm is demonstrated, enabling proximity pause and pressure-based servo position control. This innovative approach enhances the robot’s sensing ability and promotes safer and more efficient collaboration between humans and machines.

Fabrication of functionalised graphene-PAEK nanocomposites for different manufacturing processes

ABSTRACTAchieving good dispersion of graphene (GNP), in polyetheretherketone (PEEK), is challenging due to the high melt viscosity, solvent resistance and processing temperature of PEEK. In addition, certain manufacturing processes tend to enhance the anisotropy due to GNP orientation within the structure. This study investigated the fabrication of nanocomposite parts through hot compression moulding (C-MOULD) and powder bed fusion (PBF) processes, using powder with GNPs fused to the surface of polymeric particles, through a process called mechanofusion. The method applies mechanical forces of compression, shear and impact to generate a mechanical bond between materials, in this case, O2 functionalised GNP and a developmental polyaryletherketones (PAEK) grade powder. The novelty of this work is in the combination of processes used for manufacturing (material preparation and actual manufacturing processes), which are scalable and efficient in comparison with existing methods (such as solvent mixing or melt-compounding). The mechanofusion GNP-PAEK composite powders were successfully printed for the first time using the EOS P800 system with notable improvements in electrical and mechanical properties. This study highlights that the mechanofusion process could be used as an efficient process for making multifunctional nanocomposite materials and this can be combined with additive manufacturing (AM) processes to produce complex components.

Fabrication and characterization of copper and copper alloys reinforced with graphene

The consistent rise in current density within electrical wires leads to progressively more substantial heat losses attributed to the Joule effect. Consequently, mitigating the electrical resistivity of copper wires becomes imperative. To attain this objective, the development of a composite material that incorporates a more conductive reinforcement, like graphene, holds great promise. The conception of a copper/graphene composite using a powder metallurgy-based approach is presented. An optimum graphene quantity of 0.06 vol.% was obtained by calculation in order to limit the phenomenon of overlapping layers. This synthesis technique enables the dispersion of graphene and the meticulous control of the interface through the growth of CuO(Cu) nanoparticles that are tightly bonded to the reinforcement. The increase in the hardness of the various materials with separation of the graphene sheets by ultrasonic treatment (55.3 to 67.6 HV) was obtained. It is an indicator of the correct distribution of the reinforcement. The influence on the electrical properties of dendritic copper (ρe = 2.30 µΩ.cm) remains limited, resulting in a modest reduction in electrical resistance of around 1.4%. Nevertheless, for flake copper (2.71 µΩ.cm) and brass (7.66 µΩ.cm), we achieved a more substantial reduction of 2.7% and 10%, respectively. With the improvement of graphene quality, there exists a greater potential for further enhancing the electrical properties.

Experimental investigation and predictive modeling of compressive strength and electrical resistivity of graphene nanoplatelets modified concrete

Multipurpose cement composites are required for the sustainable development of the construction industry. Incorporation of nanomaterials can produce high-performing and multipurpose cement composites (CC). However, predicting the properties of these composites is challenging due to their complex composite nature and nonlinear behavior. This study investigates the integration of graphene nanoplatelets (GNPs) in concrete to enhance compressive strength and electrical properties. In addition to the experimental study, three machine learning techniques i.e., gene expression programming (GEP), support vector machine (SVM), and random forest regression (RFR), are employed to predict the compressive strength and electrical resistivity of graphene nanoplatelet modified concrete (GrNCC). The experimental results showed that GNP was evenly distributed throughout the matrix, and GrNCC exhibited enhanced compressive strength (CS) and fractional change in resistivity (FCR). GNP concentrations of 0.1% and 0.5% depict strength enhancement of 16.58% and 13.23% respectively. Similarly maximum FCR change of − 13%, and − 12.19% is observed. Moreover, GEP was the most robust ML model with mean R2 values of 0.988 and 0.74 for CS and ER respectively. In addition, SVM has R2 values of 0.93 and 0.71, and RFR shows R2 values of 0.899 and 0.671 for CS and ER respectively. GEP performed 52% and 67.5% better than SVM and RFR for CS, and 34.92% and 35.1% better than SVM and RFR for ER in terms of MAE. Furthermore, sensitivity analysis revealed that graphene content is the most important parameter contributing almost 27.3% and 29.2% for CS and ER respectively, followed by graphene dispersion and water content. Moreover, a graphical user interface (GUI) is made using a model that has been trained to predict the output values based on the input parameters. This simplifies the process and offers a valuable tool for utilizing the model's capabilities in civil engineering.

Advancements in Conductive Cotton Thread-Based Graphene: A New Generation of Flexible, Lightweight, and Cost-Effective Electronic Applications

Conductive threads have emerged as a highly promising platform for the advancement of smart textiles, enabling the integration of conductivity into fabric materials. In this study, we present a novel approach to fabricate highly flexible graphene-based smart threads, which exhibit exceptional electrical properties. Four distinct types of smart threads were meticulously prepared by drop-casting graphene dispersions onto cotton threads, utilizing various solvents. The influence of annealing temperature and the quantity of dispersed graphene on the electrical conductivity of the threads was systematically investigated. Our findings reveal that the electrical conductivity of the threads is significantly influenced by the type of solvent and the annealing temperature, while exhibiting an increasing trend with higher amounts of dispersed graphene. Remarkably, we achieved a maximum electrical conductivity of 2505.68 S cm−1 for a thread prepared with 6 mL of graphene dispersed in ethanol, annealed at a temperature of 78 °C. Furthermore, the fabricated smart threads were successfully employed as replacements for electric cables in a mobile charger and a computer mouse, demonstrating their high efficiency. This work represents a significant advancement in the development of a new generation of smart textiles, offering a simple, cost-effective, and environmentally friendly fabrication method for the production of smart threads.

Localized fabrication of flexible graphene-copper composites via a combined ultrafast laser irradiation and electrodeposition technique

Graphene-metal composites (GMC) possess superior properties, such as high specific strength, and high thermal and electrical conductivity, and have been widely used in many fields. However, the fabrication of GMC still remains to be explored, as existing methods via powder metallurgy and chemical synthesis are difficult to achieve uniform dispersion of graphene, not to mention achieving selective and localized preparation of GMC with complex patterns. In this paper, a simple method for the fabrication of graphene-copper composites (GCC) is firstly proposed by combining flexible laser irradiation and efficient electrodeposition. It not only effectively solves the problems of graphene agglomeration and inhomogeneous dispersion in GCC, but also enables the selective and precise preparation of GCC with spatial micro-patterns. Specifically, an ultrafast picosecond (ps) laser is firstly used to irradiate the polyimide (PI) film to selectively and precisely produce the desired laser-induced graphene (LIG) region. The localized deposition of copper atoms is subsequently made via the electrodeposition step, forming the flexible GCC with a laser-determined spatial pattern. The experimental study of LIG process on PI film has been carried out, and high-quality LIG region is obtained by optimizing the laser scanning path and parameters. On this basis, the regional flexible GCC of 45 μm in thickness with a compact and uniform copper layer of 20 μm has been efficiently fabricated, followed by the detailed characterizations of surface morphology and chemical composition. Furthermore, a significant enhancement of the electrical conductivity has been confirmed, as the measured value is up to 32.8 S/cm at the LIG region and further to about 60.9 S/cm at the GCC area. The mechanical properties of the obtained conductive GCC have been tested and good flexibility is confirmed by nanoindentation and bending tests, verifying its potential for a wide range of applications in flexible electronics, medical and many other fields.

Decoupling rheology from particle concentration by charge modulation: Aqueous graphene-clay dispersions

HypothesisAqueous graphene dispersions are usually obtainable by treating the surface of graphene chemically or physically. In these dispersions, the rheological properties (e.g., viscosity) are governed by a direct coupling to the graphene concentration, which limits their applicability. An alternative approach for dispersing graphene is trapping them in a viscoelastic-network formed by a co-dispersed charged fibrous-clay, Sepiolite. Contrary to surface treatment, the rheological properties of these dispersions are set by the clay particles. The rheology of charged-colloidal dispersions is governed by various parameters, including interparticle interactions. Hence, the rheology of the dispersion could be modulated by changing the clay surface charge without compromising the dispersed graphene concentration. ExperimentalThe surface charge of Sepiolite was modulated either by charge-screening (by NaCl added to the solution) or by surface-charging (by attachment of highly charged ions, e.g., HexaMetaPhosphate, HMP−) and the effect on rheology and graphene concentration was assessed. In particular, loading the dispersion with HMP− yielded low viscosity, storage, and loss moduli (two orders of magnitude lower than the corresponding HMP−-free dispersion) while the graphene concentration was maintained. We demonstrate that by this charge-modulation approach, reaching the rheological requirements of different applications without compromising on graphene concentration is plausible.

Well-Dispersed Graphene Enhanced Lithium Complex Grease Toward High-Efficient Lubrication

Graphene as a lubricating additive holds great potential for industrial lubrication. However, its poor dispersity and compatibility with base oils and grease hinder maximizing performance. Here, the influence of graphene dispersion on the thickening effect and lubrication function is considered. A well-dispersed lubricant additive was obtained via trihexyl tetradecyl phosphonium bis(2-ethylhexyl) phosphate modified graphene ([P66614][DEHP]-G). Then lithium complex grease was prepared by saponification with 12-OH stearic acid, sebacic acid, and lithium hydroxide, using polyalphaolefin (PAO20) as base oil and the modified-graphene as lubricating additive, with the original graphene as a comparison. The physicochemical properties and lubrication performance of the as-prepared greases were evaluated in detail. The results show that the as-prepared greases have high dropping point and colloidal stability. Furthermore, modified-graphene lithium complex grease offered the best friction reduction and anti-wear abilities, manifesting the reduction of friction coefficient and wear volume up to 18.84% and 67.34%, respectively. With base oil overflow and afflux, well-dispersed [P66614][DEHP]-G was readily adsorbed to the worn surfaces, resulting in the formation of a continuous and dense graphene deposition film. The synergy of deposited graphene-film, spilled oil, and adhesive grease greatly improves the lubrication function of grease. This research paves the way for modulating high-performance lithium complex grease to reduce the friction and wear of movable machinery.

Interlayer spacing control strategy to construct the rapid thermal conductivity channel in the molten salt phase change materials

With the goal of improving the thermal conductivity of inorganic salt PCMs without significantly affecting the thermal energy storage density, a functionalized modification strategy to regulate the layer spacing of nano two-dimensional (2D) materials was proposed to construct a thermal conduction pathway in phase change materials (PCMs). In the instance of graphene, we proposed hydroxylation to increase the lamellar spacing between graphene, improve its dispersion in molten salt PCMs, and speed heat transfer of graphene composite molten salt. When compared to pure graphene, the addition of hydroxylated graphene (GOH) improved the thermal conductivity of PCMs significantly. The thermal conductivity model demonstrated that the thermal conductivity pathway can be constructed by equally dispersing enough GOH to further increase the thermal conductivity. When the GOH percentage was 0.8 %, the composite's thermal conductivity was 2.60 W/(m·K), which was 118.5 % greater than the graphene composite with the same content. When the melting point was 240.00 °C, the composite material had a high latent heat of 355.52 J/g. The morphology characterization and thermal conductivity model analysis show that adjusting the layer spacing can improve graphene dispersion, facilitating the construction of thermal conduction pathway in PCMs, accelerating heat transfer, and essentially maintaining PCMs' original thermal energy storage density. Therefore, the strategy of regulating the layer spacing of 2D materials in this study has the potential to extend the application of other 2D materials used in PCMs to improve the heat storage properties.

Passivating Grain Boundaries via Graphene Additive for Efficient Kesterite Solar Cells.

Grain boundaries (GBs)-triggered severe non-radiative recombination is recently recognized as the main culprits for carrier loss in polycrystalline kesterite photovoltaic devices. Accordingly, further optimization of kesterite-based thin film solar cells critically depends on passivating the grain interfaces of polycrystalline Cu2 ZnSn(S,Se)4 (CZTSSe) thin films. Herein, 2D material of graphene is first chosen as a passivator to improve the detrimental GBs. By adding graphene dispersion to the CZTSSe precursor solution, single-layer graphene is successfully introduced into the GBs of CZTSSe absorber. Due to the high carrier mobility and electrical conductivity of graphene, GBs in the CZTSSe films are transforming into electrically benign and do not act as high recombination sites for carrier. Consequently, benefitting from the significant passivation effect of GBs, the use of 0.05wt% graphene additives increases the efficiency of CZTSSe solar cells from 10.40% to 12.90%, one of the highest for this type of cells. These results demonstrate a new route to further increase kesterite-based solar cell efficiency by additive engineering.

A simple atomization approach enables monolayer dispersion of nano graphenes in cementitious composites with excellent strength gains

Carbon nano additives (CNAs) are critical to achieving the unique properties of functionalized composites, however, controlling the dispersion of CNAs in material matrix is always a challenging task. In this study, a simple atomization approach was successfully developed to promote the dispersion efficiency of graphene nanoplatelets (GNPs) in cement composites. This atomization approach can be integrated with the direct, indirect and combined ultrasonic stirrings in a homemade automatic stirring-atomization device. Mechanical and microstructure tests were performed on hardened cement pastes blended with GNPs in different stirring and mixing approaches. Results show that the direct ultrasonic stirrings enabled more homogeneous dispersions of GNP particles with a smaller size for a longer duration. The atomized droplets with the mean size of ∼100 ​μm largely mitigated GNPs’ agglomerations. Monolayer GNPs were observed in the cement matrix with the strength gain by up to 54%, and the total porosity decrease by 21% in 0.3 ​wt% GNPs dosage. The greatly enhanced dispersion efficiency of GNPs in cement also raised the cement hydration. This work provides an effective and manpower saving technique toward dispersing CNAs in engineering materials with great industrialization prospects.

The study of structural, magnetic, and microwave absorbing properties of graphene/hexagonal ferrite for microwave absorber

This work reports the synthesis and characterization of Y-type Hexaferrite (Ba2Co2Fe12O22) and its composites with 20, 30, 40, and 50 wt% rGO. Ferrites were fabricated using the hydrothermal method and then sintered for 6 h at 1000 °C. The formation of Y-type hexaferrite (Ba2Co2Fe12O22) and Ferrites/rGO composites was confirmed using x-ray diffraction. Ferrite/rGO composites exhibited no diffraction peaks due to rGO, which may be due to staking disorders and uniformly dispersed graphene sheets. Scanning electron microscopy showed that graphene nanolayers are well-decorated with Y-type hexaferrite nanoparticles. FTIR spectra measured for Ba2Co2Fe12O22, rGO, and Ba2Co2Fe12O22/rGO nanocomposites revealed the presence of relevant functional chemical bonds. The dielectric properties studied between 1MHz-3GHz frequency range showed that composites of Ba2Co2Fe12O22/rGO perform better than pure ferrite. Diffuse reflectance spectroscopy was applied to determine the band gap, and rGO/Ferrites composites exhibited a band gap in the range of 4.4–4.6 eV. Vibrating sample magnetometer (VSM) measurements showed saturation magnetization of 26.2 emu g−1 in pure hexaferrite, which significantly lowered with rGO content in the composites. From enhanced absorption and reflection parameters of dielectric properties and magnetic loss that originate from the synergetic effect of rGO and Y-type hexaferrite (Ba2Co2Fe12O22), this study suggests lightweight, flexible, and efficient EMI shielding composites.

Study of the structure and electrical properties of graphene oxide (GO) and graphene oxide+nanocellulose (GO+NC)

Proton exchange membranes (PEMs) that function at elevated temperatures surpassing 100°C and exhibit exceptional mechanical, chemical, and thermochemical stability have garnered significant interest. This is primarily due to their practical utility in proton exchange membrane fuel cells (PEMFCs). In the present era, an extensive array of polymers and polymer-blended membranes have been scrutinized for their applicability in this domain. Each of these materials presents a set of advantages and disadvantages. However, the realm of PEMFCs is still in search of the perfect membrane endowed with distinct properties. Graphene oxide, a two-dimensional substance arising from the oxidation of graphite, has manifested itself as a promising candidate. Oxygen (O) functional groups are incorporated within the sp2 carbon (C) plane of the oxidized graphite, forming graphene oxide. This material can be synthesized by exfoliating graphite oxide, a three-dimensional carbon-based compound, into layered sheets using ultrasonic or mechanical agitation. The presence of multiple reactive oxygen functional groups renders graphene oxide suitable for a diverse array of applications, such as composite polymers, energy conversion materials, environmental safeguards, sensors, transistors, and optical components. This versatility is attributable to its outstanding electrical, mechanical, and thermal properties. Among the various methodologies for graphene oxide synthesis, the modified Hammer method stands out for its simplicity, cost-effectiveness, and high yield. This research delves into the structural analysis of graphene oxide obtained through the Hammer method, utilizing commercially available graphite. The study involves the creation of membranes based on carboxymethylcellulose (NC) that integrate dispersed graphene oxide (GO) sheets. These novel membranes, as well as pristine graphene oxide, were subjected to a comprehensive array of analytical techniques including XRD, XPS, Raman, FTIR, and SEM microscopy. Additionally, electrophysical characterizations were undertaken employing electrochemical impedance spectroscopy (EIS) measurements. The investigation uncovered that the introduction of NC into the graphene oxide matrix significantly enhances the electron conductivity of the composite membrane. Simultaneously, the presence of graphene oxide contributes to the mechanical robustness and thermomechanical stability of the membrane structure. The principal impetus behind this article lies in furnishing vital insights into the physical and structural attributes of graphene oxide membranes relevant to their deployment in hydrogen energy applications.

Graphene-containing para aramid fabric coating via surfactant assisted exfoliation of graphite

Based on existing industrial knowledge and equipment, liquid exfoliation is probably the most viable option for expanding graphene practical application fields. The method’s principal attraction is a scalable process where pristine graphite is subjected to a solvent treatment enabling the creation of graphene dispersion suitable for end applications without transition processes. The challenge is that graphene has a limited disperse ability even in solvents suitable for it, which is due to its small mixing potential and strong π-π attraction between two-dimensional graphite structures. The article discusses the possibilities of using an organic biodegradable solvent derived from natural cellulose residues Cyrene (dihydrolevoglikosenone) as a base solvent to create a liquid graphite exfoliation medium. Since the objective of obtaining graphene dispersion suitable for textile surface modification was not achieved, triethanolamine was added as a result of the search for solutions to improve the performance of the liquid medium. Several technological sequences have been developed and a comparative analysis is presented based on stereomicroscopy observations, micrographs, graphene flakes lateral dimension analysis and evaluation of dispersion adhesion intensity on the fibres of para-aramid fabric.

A Facile Graphene Conductive Polymer Paper Based Biosensor for Dopamine, TNF-α, and IL-6 Detection.

Paper-based biosensors are a potential paradigm of sensitivity achieved via microporous spreading/microfluidics, simplicity, and affordability. In this paper, we develop decorated paper with graphene and conductive polymer (herein referred to as graphene conductive polymer paper-based sensor or GCPPS) for sensitive detection of biomolecules. Planetary mixing resulted in uniformly dispersed graphene and conductive polymer ink, which was applied to laser-cut Whatman filter paper substrates. Scanning electron microscopy and Raman spectroscopy showed strong attachment of conductive polymer-functionalized graphene to cellulose fibers. The GCPPS detected dopamine and cytokines, such as tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) in the ranges of 12.5-400 µM, 0.005-50 ng/mL, and 2 pg/mL-2 µg/mL, respectively, using a minute sample volume of 2 µL. The electrodes showed lower detection limits (LODs) of 3.4 µM, 5.97 pg/mL, and 9.55 pg/mL for dopamine, TNF-α, and IL-6 respectively, which are promising for rapid and easy analysis for biomarkers detection. Additionally, these paper-based biosensors were highly selective (no serpin A1 detection with IL-6 antibody) and were able to detect IL-6 antigen in human serum with high sensitivity and hence, the portable, adaptable, point-of-care, quick, minute sample requirement offered by our fabricated biosensor is advantageous to healthcare applications.