Incorporation Of Graphene Research Articles

Effect of graphene incorporation on properties of epoxy-based self-healing coatings

Effect of graphene incorporation on properties of epoxy-based self-healing coatings

Synergistic Signal Amplification-Initiated Innovative Self-Powered Photoelectrochemical Aptasensing: An Ingenious Photocathode Activated by the High-Light-Harvesting Photoanode.

Exploiting ingenious photoelectrodes and innovative signal amplification strategies has the potential to achieve high sensitivity in self-powered cathodic photoelectrochemical (PEC) analysis. In this work, a novel self-powered PEC sensing platform was constructed by integrating a synergistic signal amplification of an ingenious photocathode with a high light-harvesting photoanode. In the dual photoelectrode-based PEC system, the amplified photocurrent signals were induced by a synergistic enhancement: (1) the photocurrent of the BiOBr photocathode was improved by the incorporation of nitrogen-doped graphene; (2) the photocurrent of the self-powered sensor was activated by the high-light-harvesting Bi2S3-C3N4 photoanode. Subsequently, the rational mechanism for synergistic signal amplification was investigated. For the construction of the sensing interface, an aptamer was introduced as the recognition element to specifically capture the streptomycin (STR) target. Under optimal conditions, the constructed self-powered aptasensor has the merits of good linear range (1 × 10-11 to 5 × 10-7 M), acceptable limit of detection (1.18 × 10-12 M), and excellent stability and selectivity for STR detection. Additionally, the proposed self-powered aptasensor showed acceptable accuracy for the detection of STR in water. Hopefully, this might stimulate more interest in designing and constructing novel platforms for exquisite photocathodic monitoring of various contaminants in the environment.

An effective strategy for improving the performance of electrodeposited Fe-W alloy plating: Tailoring microstructure by graphene incorporation

Despite the excellent performance of hard Cr plating using hexavalent chromium (Cr6+), its use is being restricted owing to recent environmental regulations. Electrodeposited Fe-W alloy is considered a possible alternative, but its high coefficient of friction (COF), high wear rate owing to tribo-oxidation, and high corrosion rate hinder its practical application. In this study, we attempted to solve these problems by modifying the microstructure of Fe-W alloy by incorporating 2D-structured graphene. The effect of graphene incorporation on the structure of the Fe-W alloy and its properties, especially microhardness, wear, and corrosion resistance, were investigated. The results showed the graphene effectively modified the columnar structure of the Fe-W alloy by inhibiting the vertical growth of clusters during electrodeposition, leading to fragmentation of the vertical cluster boundaries. This improved the hardness by as much as 17 % up to 9.1 GPa, and the corrosion resistance by changing the corrosion mechanism from localized corrosion to uniform corrosion. In addition, the graphene reduced the COF and wear rate by reducing the Fe2O3 formed by tribo-oxidation to a lower oxidation state. The structural modification of the plating by graphene incorporation thus provides an effective solution to improving the performance of Fe-W alloys.

A two-step homogenization micromechanical model for strain-sensing of graphene reinforced porous cement composites

The incorporation of graphene and its derivatives into cement for electrically conductive composites is currently under extensive investigations due to their potential applications as smart materials for large-scale self-sensing structures. It is of great importance to develop theoretical models to predict the response of the electrical conductivity of the cement composites when subjected to mechanical deformation. Experimental studies have demonstrated that pores and rippled graphene fillers exist in the cement composites. However, currently there are limited theoretical models to predict the electrical conductivity and piezoresistive properties of the cement composites with incorporating the effects of pores and graphene ripples. To address the research gap, this paper develops a two-step micromechanical modelling to predict the effective electrical conductivity and the response of conductivity to compression strain of graphene nanoplatelet (GNP) reinforced cement composites (GNPRCCs) with considering the effects of pores and graphene ripple for the first time. The effective medium theory and Mori-Tanaka model are employed to homogenize the GNP and pores as inclusions with considering several influencing mechanisms. Parametric study is carried out to identify the effects of the attributes of GNPs, pores and electron tunnelling on the electrical and piezoresistive properties of the GNPRCCs. It is found that the piezoresistive response is proportional to porosity when the conductive behavior of GNPRCC is dominated by the tunnelling effect. Increasing porosity has a negative impact on the strain-sensing performance of the GNPRCCs once the conductive network is formed.

Mechanical and surface properties of a 3D-printed dental resin reinforced with graphene

Objectives: Commercial photocurable polymers used in dental additive manufacturing still have mechanical limitations. The incorporation of graphene may provide interesting advantages in this field. This study aimed to evaluate in vitro the effect of adding graphene nanoparticles to a 3D-printed polymethylmethacrylate dental resin in terms of surface roughness, flexural properties, and hardness. Methods: A 3D-printed dental resin (Dental Sand, Harz Lab) was loaded with four different graphene nanoplatelet (Graphenest) concentrations: 0.01wt%, 0.1wt%, 0.25wt%, and 0.5wt%. The neat resin was used as the control group. The surface roughness was measured with a contact profilometer using bar-shaped specimens (50x10x4mm). The flexural strength of specimens (80x10x4mm) from each group was calculated using the 3-point bending test in a Universal Test Machine. Hardness shore D was measured using a manual durometer on round-shaped specimens (12x6mm). Data were evaluated using the Kruskall-Wallis test followed by post-hoc Bonferroni corrected pairwise inter-group comparisons. Statistical significance was set at p<0.05. Results: Graphene improved 3D-printed PMMA resin hardness with statistical significance at a concentration of 0.01wt% (p=0.043). Surface roughness increased with graphene concentrations above 0.01wt%, with statistically significant differences at 0.25wt% (p=0.006) and 0.5wt% (p=0.005) concentrations. Flexural properties worsened with increased graphene concentrations, and these differences were significant in the concentrations of 0.25wt% (p=0.028) and 0.5wt% (p=0.006). Conclusions: The use of graphene as a mechanical reinforcement nanomaterial seems to be viable at low concentrations without prejudice to the surface roughness of a 3D-printed polymethylmethacrylate resin.

Graphene-bioactive glass composites: Structural, Vickers hardness, and gamma-ray attenuation characteristics

Introduction: Graphene-based materials have gained increasing attention for use in radiation attenuation applications. In this study, pristine graphene nanoplatelet-containing (1, 3, 5, and 10 wt%) borate-based bioactive glass composites were prepared.Methods: Structural properties, Vickers microhardness, and gamma-ray radiation shielding properties of the fabricated composites were examined in detail.Results and Discussion: Results revealed that the inclusion of the graphene in the glass matrix led to a decrease in the bulk density of the glass-based composites from 2.41 to 2.31 g/cm3. Similarly, a decrease in Vickers hardness was obtained as the graphene concentration was increased due to a convoluted effect of the non-uniform distribution of graphene nanoplatelets in the bioactive glass matrix and the higher residual porosity. Vickers hardness of the bare and the 10 wt% graphene-containing bioactive glass discs were measured to be 5.03 ± 0.28 GPa and 1.87 ± 0.56 GPa, respectively. On the other hand, the incorporation of graphene starting from 3 wt% decreased the crack propagation after indentation which may be attributed to an increase in fracture toughness. In the study, fundamental gamma ray absorption properties of graphene-containing bioactive glasses were examined in the 0.015–15 MeV incident photon energy range. For this purpose, the Py-MLBUF code was employed to determine gamma ray absorption parameters. Results showed that linear attenuation coefficients of the glass-based composites decreased due to a decrease in the density of the samples. On the other hand, as graphene was incorporated into the bioactive glass structure, exposure buildup factor and energy absorption buildup factor values increased. The growing graphene ratio in the glass structure contributed negatively to the photon’s tendency to interact with the material.

Microstructure and micro-mechanical properties of friction stir processed Al 5086-based surface composite

The present research work investigates the microstructure and mechanical properties of friction stir processed aluminium alloy 5086 based surface composite at micro-level. Towards the fabrication of surface composite, graphene and silicon carbide nano-particulates were introduced as a reinforcing medium. The mechanical properties at the micro-level were evaluated via in-situ micro-pillar compression. Based on experimental data, it was found that friction stir processing introduced severe plastic deformation, together with uniform distribution of the constituents phases and ensure grain refinement (from 4.19 µm to 1.59 µm), compared to the bulk material. This microstructural development had a positive impact to increase the compressive strength of the friction stirred processed composite, up to 193.3 MPa, compared to 147.8 MPa to that of bulk material. In addition to that, the deformation of the material possesses ductile fracture with enhanced plasticity, due to the incorporation of nano-particulate graphene and silicon carbide.

Review of Flexible Supercapacitors Using Carbon Nanotube-Based Electrodes

Carbon nanotube (CNT)-based electrodes in flexible supercapacitors have received significant attention in recent years. Carbon nanotube fiber fabrics (CNT-FF) have emerged as promising materials due to their high surface area, excellent conductivity, and mechanical strength. Researchers have attempted to improve the energy density and rate performance of CNT-FF supercapacitor electrodes through various strategies, such as functionalization with conductive materials like MnO2 nanoparticles and/or incorporation of graphene into them. In addition, the utilization of CNTs in combination with thin metal film electrodes has also gained widespread attention. Research has focused on enhancing electrochemical performance through functionalizing CNTs with conductive materials such as graphene and metal nanoparticles, or by controlling their morphology. This review paper will discuss the recent developments in supercapacitor technology utilizing carbon nanotube-based electrodes, including CNT fiber fabrics and CNTs on thin metal film electrodes. Various strategies employed for improving energy storage performance and the strengths and weaknesses of these strategies will be discussed. Finally, the paper will conclude with a discussion on the challenges that need to be addressed in order to realize the full potential of carbon nanotube-based electrodes in supercapacitor technology.

Mesoporous Materials of the MCM Type: Synthesis, Application, use of Ionic Solids and Functionalization with Graphene: A Review

The wide applicability of silica-based mesoporous molecular sieves in the most different scientific areas, such as catalysis, adsorption, drug delivery systems, sensors, CO2 capture, enzyme immobilization, so on, is justified by their unique textural and structural characteristics. These materials exhibit high porosity, high specific surface area, limited pore distribution and controllable morphology what makes them adaptable and versatile. This review will address the latest in relation to molecular sieves of the M41S family, as well as their synthesis routes, highlighting the role of ionic solids and ionic liquids as structure-directing agents, the influence of heteroatoms addition (M+/MCM), focusing on graphene incorporation (graphene/MCM), the means of characterization of these materials and their main applications. Considering the approaches that have been widely explored in the literature, it is safe to say that, depending on the synthesis route, these materials can be considered environmentally friendly, as it is possible to obtain them using clean reagents in one-pot syntheses. These materials already provide several solutions to nanoscale problems and its functionalization with graphene and the use of ionic solids and ionic liquids as SDA can further improve its performance.

Flammability and vibrational study of graphene incorporated epoxy/ramie/glass hybrid nanocomposite

AbstractHybrid polymer composites are vastly used in aerospace, construction, and automotive fields. This study aims to analyze the flammability and vibrational behavior of graphene incorporated epoxy/ramie/glass (ERG) hybrid nanocomposite. The samples were prepared with different weight percentage of graphene (GR) through hand layup method, followed by vacuum bag technique. The samples were analyzed for water intake, porosity, mechanical strength, fractography, vibrational property together with flammability of the material. GR addition depletes water intake and porosity by 11.5% to 5.3% and 6.2% to 2.2%, respectively. It increases hardness and flexural strength up to 25% and 41%, with a reduction in tensile property of the composites. Besides, GR nanocomposites show improved damping properties, owing to stick‐slip mechanism exhibited at epoxy and GR interface. Also, GR addition declines burning rate of ERG at high concentrations since it does not score any grade in flammability test. This work found that the incorporation of GR in ERG composite enhances mechanical properties and decreases water intake. A decrease in the burning rate of the ERG composite could be achieved by incorporating graphene particles, which could be used for structural applications (car door‐panels, ballistic, and aerospace) leading to delay in burning rate of the developed composites when exposed to fire during accidents.

In Vitro Mechanical Properties of a Novel Graphene-Reinforced PMMA-Based Dental Restorative Material.

Recent studies suggest that the incorporation of graphene in resin-based dental materials might enhance their mechanical properties and even decrease their degree of contraction during polymerization. The present study aimed at comparing the three-point flexural strength (FS), the compressive strength (CS), and the Vickers hardness (VH) of a CAD/CAM poly-methylmethacrylate (PMMA)-based resin, a recently introduced graphene-reinforced CAD/CAM PMMA-based resin (G-PMMA), and a conventional dental bis-acryl composite resin (BACR). No significant differences (p > 0.05) were detected among the materials in terms of flexural strength. On the other hand, a mean flexural modulus value of 9920.1 MPa was recorded in BACR group, significantly higher compared to the flexural modulus detected for G-PMMA (2670.2 MPa) and for conventional PMMA (2505.3) (p < 0.05). In terms of compressive modulus (MPa) and compressive strength (MPa), BACR was significantly stiffer than PMMA and G-PMMA. Concerning VH measurements, a significantly increased hardness emerged comparing the BACR group (VH 98.19) to both PMMA and G-PMMA groups (VH 34.16 and 34.26, respectively). Based on the finding of the present study, the graphene-reinforced (PMMA)-based polymer herein tested was not superior to the conventional PMMA and seemed not able to be considered as an alternative material for permanent restorations, at least in terms of hardness and mechanical response to compressive stress. More research on the mechanical/biological properties of G-PMMAs (and on graphene as a filler) seems still necessary to better clarify their potential as dental restorative materials.

Novel energy bandgap formation of organic solution doped graphene membrane for semiconductor applications

In this work, the electrolyte nano fibrous solution is prepared using corn husk through a chemical process. This study explores the new aspect of producing sizeable and tunable bandgap in graphene by doping organic nanoporous solution as a membrane. The energy bandgap of organic doped graphene membrane varies from 2.313 eV to 2.502 eV. It is noted that the organic nanoporous solution as a membrane also has a bandgap under with (2.665 eV) and without PVA (3.761 eV). The membrane is produced by the phase inversion process. The incorporation of graphene in green solution also exhibits conductive properties like organic nanoporous solution which in terns used as electrolytes to produce electricity. It is the first successful attempt to create a direct graphene bandgap with organic doping but it still requires more research for a better understanding of the properties for future applications. This concept can also be used where bandgap is a very concerning issue. The physical properties of with and without a graphene-based organic membrane are examined by Scanning Electron Microscope Test (SEM), Fourier Transform Infrared Spectroscopy Test (FTIR), and Ultra Violate Test (UV). Sample 4 has a superior surface morphology, which means the particle dispersion is more homogeneous than the others. There are porosities in all the samples.

An Effective Strategy for Improving the Performance of Electrodeposited Fe-W Alloy Plating: Tailoring Microstructure by Graphene Incorporation

An Effective Strategy for Improving the Performance of Electrodeposited Fe-W Alloy Plating: Tailoring Microstructure by Graphene Incorporation

Graphene coupled flower-like oxidized-polyacrylonitrile as high-performance anodes for sustainable lithium-ion batteries.

In situ polymerization of acrylonitrile and graphene oxide in combination with thermal treatment was readily performed to produce robust hierarchical hybrids containing flower-like oxidized-polyacrylonitrile, which synergistically couple conductive graphene and a multi-electron redox-active matrix, affording large reversible capacity, high rate capability, and long cycle life toward cost-efficient and sustainable batteries.

Advancements and Prospects of Composites Consisting of Carbon-NanomaterialDispersed Liquid Crystals

This research paper presents a thorough examination of the progress and potential of composites that consist of carbon nanomaterials dispersed in liquid crystals. These composites have attracted considerable interest in recent years due to their unique combination of properties and their wide range of applications. Specifically, this paper focuses on the incorporation of carbon nanotubes (CNTs) and graphene into liquid crystal matrices. The synthesis methods utilized for the preparation of these composites, including dispersion techniques and alignment strategies, are discussed in detail. Moreover, the paper investigates the effects of incorporating carbon nanomaterials on the structural, electrical, and optical properties of liquid crystals. The potential applications of these composites in various fields such as optoelectronic devices, sensors, and energy storage systems are also explored. Furthermore, significant attention is given to recent experimental findings and theoretical studies, which demonstrate the remarkable advancements achieved in the performance of these composites. Moreover, the research delves into forthcoming opportunities and obstacles in the domain while emphasizing scalability, stability, and device integration. Collectively, this scholarly article sheds light on the progress and possibilities of composites that encompass carbon-nanomaterial-dispersed liquid crystals, thus underscoring their prospective role in emerging technologies

STRUCTURAL AND THERMAL STABILITY OF FUNCTIONALIZED GRAPHENE INCORPORATED POLYURETHANE NANOCOMPOSITE FOAM

The thermal stability and morphology of polyurethane nanocomposite foams reinforced with chemically modified Fenton graphene (FG), graphene oxide (GO), or reduced graphene oxide (rGO) were investigated. The polyurethane (PU) polymeric nanocomposite foams having 0.5 to 2.0 wt.&amp;#37; were prepared using a thermo-reversible solution method involving a supramolecular self-assembly process. The effect of edge and surface oxidization morphology of functionalized graphene/PU foams was characterized by scanning electron microscopy and X-ray diffraction methods. The thermal stability of the polyurethane nanocomposite foam was investigated by thermo-gravimetric analysis (TGA). The thermal stability of 0.5 wt.&amp;#37; FG-based nanocomposite foam was more as compared to 0.5 wt.&amp;#37; of GO and rGO-based nanocomposite foam.

Electrochemical performance of aqueous hybrid supercapacitor based on LiFePO4/Si/graphene composite

Aqueous hybrid supercapacitors (HS) are a viable alternative to achieve low-cost, environmentally friendly, and safer energy storage technologies. Herein, lithium iron phosphate modified silicon and graphene derivatives (LFP/Si/graphene) are constructed as the cathode, and graphene nanoplatelets (GNPs) as the anode for an aqueous HS. The incorporation of GNPs and reduced graphene oxide (rGO), which is the source of graphene derivatives (graphene) in the composite, has played the role of an electronic conductivity enhancer for LFP/Si structure in the framework structure of the rGO film. Therefore, Si is able to perform its role effectively in avoiding surface instability issues and preventing the side reaction of LFP in aqueous electrolyte. The electrochemical performance is evaluated in a 1 M Li2SO4 aqueous electrolyte that has been thoroughly deaerated with high-purified argon (Ar) gas to remove any dissolved oxygen that might interfere with the analysis. The Ar blanketing in the electrolyte intensified the electrochemical performance by 60 % as compared to the Ar-free electrolyte. The coated LFP by 0.5 w/w% Si with incorporation of graphene (LFP/Si0.5/graphene) for electronic conductivity enhancement in Swagelok-type cells has an exceptional specific capacitance of 272.6 F/g and a highly improved cycle life, which shows 87.2 % capacitance retention after 5200 cycles. Moreover, a different assembly of a close-to-current commercial format of roll-type cell is also studied, and it exhibits slightly higher in specific capacitance of 301.3 F/g with energy and power density of 35.62 Wh kg−1 with 922.53 W kg−1, respectively. Therefore, both cell configurations using LFP/Si0.5/graphene display promising applications of the HS, which have the potential to slowly build themselves into a vital role in hybrid-electric technology.

Molecular Dynamics Simulation of the Thermomechanical and Tribological Properties of Graphene-Reinforced Natural Rubber Nanocomposites

The thermomechanical and tribological properties of graphene (GNS)-reinforced NR were investigated using molecular dynamics (MD) simulations. The amorphous molecular dynamics models of two nanocomposites, i.e., natural rubber (pure NR) and graphene/natural rubber (GNS/NR), were established. In addition, the thermodynamic properties of the two materials, before and after the incorporation of graphene into the natural rubber matrix, were investigated through analytical comparison. The results showed that after the graphene was added to the rubber matrix as a reinforcing material, the elastic modulus and shear modulus were increased by 110% and 94.8%, respectively, the tensile property was increased by 178%, the overall thermal conductivity of the composite system was increased by 59%, the glass transition temperature increased from 223 K to 236 K, and the rigidity of the material matrix was significantly improved. The inherent interactions and wear mechanisms of the polymer nanocomposites were discussed at the atomic scale by analyzing the changes in temperature, atomic velocity, relative atomic concentration, and radial distribution functions at the friction interface in the thickness direction.

Study on the Influence of Graphene Content Variation on the Microstructure Evolution and Properties of Laser Additive Manufacturing Nickel-Based/SiC Composite Cladding Layer on Aluminum Alloy Surface.

A Ni25-10% SiC-X% graphene (mass fraction X = 0, 0.5, 1.0, 1.5) composite cladding layer was prepared on a 6063 aluminum alloy substrate using laser cladding in order to enhance the comprehensive performance of the aircraft refueling interface. The effect of the graphene content on the organization and properties of nickel-based silicon carbide composite cladding layers was investigated by laser melting. The macroscopic morphology, microstructure, hardness, elemental changes, corrosion and wear resistance of the cladding layer were studied by optical microscopy, scanning electron microscopy, a hardness tester, an X-ray diffractometer, an electrochemical workstation and an M-2000 frictional wear tester. The results indicated that the nickel-based clad layer without graphene incorporation had the worst forming, with a large number of pores and cracks in the cladding layer. Because graphene agglomerated easily, cracks were regenerated when the content of graphene was higher than 0.5%. The material phases of the cladding layer without graphene incorporation were mainly: Al3Ni2, Fe3Si and SiC. Due to the addition of graphene, the clad layer of specimen 2 was refined and a large number of hard phases, such as CrC and Cr23C6, were generated, which led to the increase in the hardness of the clad layer. When the content of graphene was further increased, the number of hard phases such as CrC and Cr23C6 produced in the cladding was relatively reduced due to the agglomeration of graphene, and the hardness of the cladding was reduced. As the impermeability of graphene reduces the diffusion of corrosive media to the substrate, the generation of hard-phase Al3Ni2 in the cladding layer makes the corrosion resistance of the cladding layer increase with the increase in graphene mass fraction. The result is that, when the content of graphene was 0.5%, the overall performance of the clad layer was the best, where its average hardness was increased by 40%, the average coefficient of friction was reduced by 12.7% and the wear rate was reduced by 60%.

Ultra-fast self-healable stretchable bio-based elastomer/graphene ink using fluid dynamics process for printed wearable sweat-monitoring sensor

The practical application of wearable real-time monitoring systems is currently restricted by the irreversible mechanical damage and fracture of their sensors during physical activity, which has inspired the development of self-healable ink materials. However, progress in this field is limited by the difficulty of combining high mechanical strength with high conductivity and realizing scalable and efficient fabrication. Herein, a fluid dynamics process is used to prepare a self-healable, robust, and conductive ink through the incorporation of graphene into a self-healing polymer, namely poly(1,4-cyclohexanedimethanol succinate-co-citrate). The corresponding screen-printed serpentine-structured electrode exhibits spontaneous conductivity self-healing during 10 cut-heal cycles and at a tensile strain of 200% under ambient conditions. These unique properties are used to fabricate a highly stretchable electrochemical Na+ sensor with a high self-healing efficiency (average sensitivity retention of 99%). On-body tests reveal that this wearable sensor is well suited for the real-time monitoring of sweat during physical exercise and is capable of autonomous repair after mechanical cutting, showing a healing time of ∼12 s. Thus, our work paves the way to the commercialization of devices typically requiring a combination of mechanical resilience and stable electrical performance, e.g., e-skin, sweat sensors, soft robotics, and biofuel cells.