Graphene-based Nanocomposites Research Articles

Broadband and strong electromagnetic wave absorption of epoxy composites filled with ultralow content of non-covalently modified reduced graphene oxides

High-efficiency microwave absorption epoxy nanocomposites filled with ultralow content of non-covalently modified reduced graphene oxides (rGO) are prepared via an in-situ polymerization method. Here, the porous and folded rGO nanosheets are successfully functionalized by strong π-π interaction between conjugated imidazole and graphene sheets. The combination of electron microscope and synchronous radiation X-ray small angle scattering (SAXS) techniques unambiguously illustrates that the non-covalently modified graphene nanosheets in the epoxy composites are well-dispersed and extensively winkle. Hence, compared with pristine rGO/epoxy composites, the composites containing the highly dispersed rGO demonstrate more ideal impedance matching and stronger microwave dissipation based on the experimental and simulated results. The composites remarkably achieve excellent microwave absorptions (minimum reflection loss of −65 dB, with a matching thickness of 1.8 mm), an extremely broad absorbing bandwidth of 7.48 GHz (RL < −10 dB) and ultralow filler loading (1–2 wt%). Moreover, the composites possess high hydrophobicity, endowing them attractive functions of self-cleaning. This work provides a promising, facile and scalable approach for designing and fabricating graphene-based nanocomposites with hydrophobicity and excellent microwave absorption capacities.

Ionic liquid-assisted pickering emulsion synthesis of hierarchical porous carbon wrapped graphene nanosheets for high performance lithium-sulfur batteries

Graphene-based nanocomposites with unique two-dimensional (2D) structural feature have become the most potential candidate for energy storage systems due to the excellent electrical conductivity and large specific surface area of graphene sheets. However, the aggregation of graphene nanosheets inhibits their applications in lithium-sulfur batteries. Here we tackle this problem by designing a porous carbon wrapped graphene nanosheet (M-GN) via a facile IL-microemulsion method. During the Pickering emulsion process, graphene oxide (GO) serves as surfactant and the templates, while the hydrophobic ionic liquid ([BMIm][FeCl4]) stabilizes the GO and forms the emulsion environment. The electrostatic effect between negative graphene oxide (GO) and positive cation 1-butyl-3-methylimidazolium (BMIm+) helps to form a stabilized system, which can facilitate the uniform growth of the carbon layers on GO. The obtained S/M-GN cathode delivers a high discharge capacity of 1331 mA h g−1 at 0.1C and 757 mA h g−1 after 100 cycles at 0.5C. The innovative IL-microemulsion method provides us with a new avenue for the synthesis of effective materials for energy storage devices.

Graphene-based magnetic metal organic framework nanocomposite for sensitive colorimetric detection and facile degradation of phenol

Abstract Phenol is a toxic and widely spread as environmental pollutants; the sensitive detection and efficient removal are quite important but challenging. Herein, we take the intrinsic advantages of graphene-based magnetic metal organic framework (MOF) composite as mimic enzyme sensor and Fenton-like catalyst for the colorimetric detection and degradation applications. In this work, magnetic Fe 3 O 4 decorated graphene MOF composite (Fe 3 O 4 /rGO/MOF) was fabricated by a simple strategy for the purpose of well-distributed porous MOF on basal planes of magnetic graphene. The adhesive coating of tannic acid film on both side of magnetic graphene was explored as the directing agent for the controllable self-assembly of MOF. Interestingly, the Fe 3 O 4 /rGO/MOF represent excellent mimic enzyme properties, which can detect phenol based on a visual colour change in water solution. The mimic enzyme senor can oxidize 4-aminoantipyrine in the presence of H 2 O 2 and exhibit strong affinity and selectivity in phenol detection. Simultaneously, Fe 3 O 4 /rGO/MOF also display high degradation ability towards phenol removal. These results indicate that the bifunctional composite can act both as colorimetric senor and Fenton-like catalyst, it would facilitate the real-time monitoring of water quality and wastewater treatment.

Activating microwave absorption via noncovalent interactions at the interface based on metal-free graphene nanosheets

Metal-free graphene-based nanocomposites with small organic molecules interaction are studied as a lightweight, wide bandwidth, and strong absorption microwave absorption material. During hydrothermal process, graphene oxide (GO) precursors are reduced and aggregated into 3D porous network structure. Meanwhile, anthraquinone molecules are intercalated and immobilized on RGO surface through noncovalent π–π stacking. For the obtained RGO@anthraquinone, noncovalent functionalization at interface can modify the electronic states and regulate the electrical conductivity of graphene substrate and its sheet-like structure can be largely maintained. Integrating the intrinsic 3D porous structure, good impedance matching, high conductive loss, and noncovalent interaction, the as-achieved RGO@anthraquinone composites exhibit excellent microwave absorption performance in the X and Ku band. Such as RGO@2-hydroxyanthraquinone (2-HAQ), its optimal absorption toward microwave can reach −54.2 dB at 12.8 GHz with a thickness of 3.0 mm, and its effective absorption bandwidth lower than −10 dB exceeds 7.0 GHz (from 10.96 to 18.0 GHz). When the thickness is controlled between 2.8 and 3.5 mm, the effective absorption bandwidth can cover the whole X and Ku bands (8.0–18.0 GHz). This opens ways to achieve new microwave absorbers with high-performance and provides more opportunities to activate MA behavior on carbon-based metal-free absorbers.

Constrained melting of graphene-based phase change nanocomposites inside a sphere

In the present work, the melting behavior of a fatty acid-based phase change material (PCM) with the addition of functionalized graphene nanoplatelets in a spherical capsule was experimentally studied. The fatty acid-based PCM (OM 08) has been selected for the air-conditioning application with a phase change temperature of 8 °C. The PCM-based nanocomposite samples were prepared by covalent functionalization method. The volume percentage of the functionalized graphene nanoplatelets varied from 0.1 to 0.5% with an increment of 0.1%. The thermal conductivity and rheological properties of the PCM nanocomposites were measured experimentally by transient hot wire method and rheometer, respectively. The maximum enhancement in thermal conductivity for 0.5 vol% of graphene nanoplatelets was found to be ~ 102%. The rheological test found that the addition of graphene nanoplatelets in the PCM resulted in the transition of Newtonian behavior to non-Newtonian behavior at lower shear rates. The viscosity of the PCM nanocomposites increases with volume fraction. Initially the pure PCM and PCM nanocomposites were solidified individually in a spherical capsule at different bath temperatures of 2 °C and − 10 °C. Then the solidified samples were kept in a constant temperature bath at 31 °C, and the melting characteristics were studied. The melting time of the PCM nanocomposite was reduced significantly with the addition of 0.5 vol% of graphene nanoplatelets by ~ 26% and ~21% for the PCM initial temperature of − 10 °C and 2 °C, respectively.

Graphene-based polymeric nano-composites: an introspection into functionalization, processing techniques and biomedical applications

Although, there have been numerous efforts in synthesis of polymers, their mechanical properties have limited their applications. Graphene has been investigated for excellent properties such as superior mechanical properties, high thermal conductivity that has attracted the attention of scientific community to employ graphene as a filler material in polymeric matrices to form composites with multi-functional capabilities. The excellent properties possessed by Graphene has motivated users to fabricate flexible nanocomposites that can be used for applications requiring superior mechanical, chemical and thermal performances. Characteristics of both the components if explored synergistically through proper structural and interfacial organization. The investigation in this direction has resulted into combination of graphene with variety of polymeric materials and hence the development of different graphene-based nanocomposites. The present work reviews the application of graphene-based nanocomposites in the biomedical domain. With this objective, the polymeric matrices suitable for biomedical applications as well as the techniques of producing graphene polymeric nanocomposites have been discussed. Finally the application particularly in biosensing, wound healing and drug delivery system has been discussed.

Multifunctional Thin-Film Nanofiltration Membrane Incorporated with Reduced Graphene Oxide@TiO2@Ag Nanocomposites for High Desalination Performance, Dye Retention, and Antibacterial Properties.

High desalination performance, dye retention, and antibacterial properties were achieved with a multifunctional thin-film nanocomposite (MTFN) membrane, fabricated by the incorporation of a novel nanocomposite structure of reduced graphene oxide@TiO2@Ag (rGO@TiO2@Ag) into the polyamide active layer. The specific characteristics of the graphene-based nanocomposite, synthesized by the microwave-assisted irradiation process, favored water channelization and provided superhydrophilicity and antibacterial properties to the MTFN membranes. In comparison with the conventional methods, such as multistep chemical process using strong agents for reduction and long-term energy-consuming hydrothermal process, microwave irradiation facilitated a green, fast, and cost-effective route for the fabrication of GO-based nanocomposites for multifunctional applications. Interfacial polymerization was performed on a polyethersulfone/Si3N4 robust hollow fiber substrate using m-phenylenediamine aqueous solution and 1,3,5-benzenetricarbonyltrichloride organic solution. The structural and chemical characteristics of the synthesized nanocomposites and the MTFN membranes were thoroughly studied by a series of characterization analyses (transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy). The physicochemical properties and the nanofiltration performance of the MTFN membranes were investigated after the incorporation of rGO@TiO2@Ag at various concentrations. The water contact angles confirmed the superb surface hydrophilicity of the MTFN membranes. High permeability (52 L·m-2·h-1), desalination (96% for 1 g/L Na2SO4 feed solution), and dye retention (98% for 0.5 g/L rose bengal feed solution) were recorded for MTFN enriched with 0.2 wt % rGO@TiO2@Ag. A 90% reduction in the number of viable bacteria ( Escherichia coli), after 3 h of contact with MTFN membranes, confirmed the superior antibacterial activity of the produced membranes.

The Effect of Hexamethylene Diisocyanate-Modified Graphene Oxide as a Nanofiller Material on the Properties of Conductive Polyaniline.

Conducting polymers like polyaniline (PANI) have gained a lot of interest due to their outstanding electrical and optoelectronic properties combined with their low cost and easy synthesis. To further exploit the performance of PANI, carbon-based nanomaterials like graphene, graphene oxide (GO) and their derivatives can be incorporated in a PANI matrix. In this study, hexamethylene diisocyanate-modified GO (HDI-GO) nanosheets with two different functionalization degrees have been used as nanofillers to develop high-performance PANI/HDI-GO nanocomposites via in situ polymerization of aniline in the presence of HDI-GO followed by ultrasonication and solution casting. The influence of the HDI-GO concentration and functionalization degree on the nanocomposite properties has been examined by scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile tests, zeta potential and four-point probe measurements. SEM analysis demonstrated a homogenous dispersion of the HDI-GO nanosheets that were coated by the matrix particles during the in situ polymerization. Raman spectra revealed the existence of very strong PANI-HDI-GO interactions via π-π stacking, H-bonding, and hydrophobic and electrostatic charge-transfer complexes. A steady enhancement in thermal stability and electrical conductivity was found with increasing nanofiller concentration, the improvements being higher with increasing HDI-GO functionalization level. The nanocomposites showed a very good combination of rigidity, strength, ductility and toughness, and the best equilibrium of properties was attained at 5 wt % HDI-GO. The method developed herein opens up a versatile route to prepare multifunctional graphene-based nanocomposites with conductive polymers for a broad range of applications including flexible electronics and organic solar cells.

Preparation and Properties of Graphene-based Inorganic Nanocomposites

Graphene is a two-dimensional hexagonal monoatomic layer crystal composed of carbon atoms, which exhibits the shape of a honeycomb and plays an important role in the fields of optics and mechanics. It also has the advantages of high specific surface area, strong chemical stability and special planar structure. It is an ideal carrier for carrying various inorganic compounds and is suitable for the development of high performance graphene-based inorganic nanocomposites.[1] Based on this, the paper introduces the characteristics of graphene, expounds the related content of graphene-based inorganic nanocomposites, and studies the preparation methods and properties of graphene-based inorganic nanocomposites.

Additive Manufacturing of PLA-Based Composites Using Fused Filament Fabrication: Effect of Graphene Nanoplatelet Reinforcement on Mechanical Properties, Dimensional Accuracy and Texture.

Fused filament fabrication (FFF) is a promising additive manufacturing (AM) technology due to its ability to build thermoplastics parts with advantages in the design and optimization of models with complex geometries, great design flexibility, recyclability and low material waste. This technique has been extensively used for the manufacturing of conceptual prototypes rather than functional components due to the limited mechanical properties of pure thermoplastics parts. In order to improve the mechanical performance of 3D printed parts based on polymeric materials, reinforcements including nanoparticles, short or continuous fibers and other additives have been adopted. The addition of graphene nanoplatelets (GNPs) to plastic and polymers is currently under investigation as a promising method to improve their working conditions due to the good mechanical, electrical and thermal performance exhibited by graphene. Although research shows particularly promising improvement in thermal and electrical conductivities of graphene-based nanocomposites, the aim of this study is to evaluate the effect of graphene nanoplatelet reinforcement on the mechanical properties, dimensional accuracy and surface texture of 3D printed polylactic acid (PLA) structures manufactured by a desktop 3D printer. The effect of build orientation was also analyzed. Scanning Electron Microscope (SEM) images of failure samples were evaluated to determine the effects of process parameters on failure modes. It was observed that PLA-Graphene composite samples showed, in general terms, the best performance in terms of tensile and flexural stress, particularly in the case of upright orientation (about 1.5 and 1.7 times higher than PLA and PLA 3D850 samples, respectively). In addition, PLA-Graphene composite samples showed the highest interlaminar shear strength (about 1.2 times higher than PLA and PLA 3D850 samples). However, the addition of GNPs tended to reduce the impact strength of the PLA-Graphene composite samples (PLA and PLA 3D850 samples exhibited an impact strength about 1.2–1.3 times higher than PLA-Graphene composites). Furthermore, the addition of graphene nanoplatelets did not affect, in general terms, the dimensional accuracy of the PLA-Graphene composite specimens. In addition, PLA-Graphene composite samples showed, in overall terms, the best performance in terms of surface texture, particularly when parts were printed in flat and on-edge orientations. The promising results in the present study prove the feasibility of 3D printed PLA-graphene composites for potential use in different applications such as biomedical engineering.

Electrochemical co-deposition synthesis of Au-ZrO2-graphene nanocomposite for a nonenzymatic methyl parathion sensor

For the first time, a simple electrochemical co-deposition was utilized to synthesis the gold and zirconia nanocomposites modified graphene nanosheets on glassy carbon electrode (Au-ZrO2-GNs/GCE) for electrocatalytic analysis of methyl parathion (MP). According to Field-Emission Scanning Electron Microscopy (FE-SEM), Transmission Electronic Microscopy (TEM) and X-Ray Diffraction (XRD), the gold nanoparticles were uniformly distributed on the surface of graphene-based nanocomposite. The Au-ZrO2-GNs/GCE based sensor exhibited superior capacity for MP detection, ascribed to the strong affinity of zirconia towards the phosphoric group, as well as the high catalytic activity and good conductivity of Au-GNs. The best fabrication and work conditions were then obtained by systematically optimization of the electrodeposition process, pH value and enrichment time. Compared to the gold nanoparticles, zirconia or graphene modified electrodes, AuZrO2-GNs/GCE sensor displayed superior electro-catalytic response toward MP oxidation. The sensor response current of square wave voltammetry was highly linearly correlated with the MP concentrations range of 1–100 ng mL−1 and 100–2400 ng mL−1 with the detection limit of 1 ng mL−1. The Au-ZrO2-GNs/GCE nanocomposite sensor showed excellent accuracy and reproducibility for detection of MP in Chinese cabbage samples, providing a new method for efficient pesticide detection in practical applications.

Efficient Mechanochemical Preparation of Graphene-Like Molybdenum Disulfide and Graphene-Based Composite Electrocatalysts for Hydrogen Evolution Reaction

Graphene-like MoS2 and graphene-based (gMoS2/Gr, Gr@gMoS2, and gMoS2@Gr) nanocomposites, which are able to operate as electrocatalysts of water splitting with hydrogen evolution, were prepared by solventless mechanochemical delamination of bulk molybdenum disulfide and graphite. It was shown that the sequence of nanostructuring significantly affects both the morphology and the electrocatalytic properties of the prepared nanocomposites. The material prepared by sequential mechanochemical treatment of molybdenum disulfide and graphite—gMoS2@Gr—is characterized by significant delamination of both components with nearly complete disruption of the layer ordering, few-layer MoS2 nanoparticles with higher degree of defectiveness, the graphene component with sufficiently large ordered regions, due to which it exhibited the best electrocatalytic performance with the Tafel slope of 60 mV/dec and the overvoltage of 195 mV at the current density of 10 mA/cm2 (or specific current ~ 17 A/g). It was shown that gMoS2@Gr nanocomposite as HER electrocatalyst can be used as an effective counter electrode in photoelectrochemical cells, providing the photocurrent of 1 mA/cm2 at the voltage of 365 mV. As a whole, the presented data show that gMoS2@Gr nanocomposite is an efficient HER electrocatalyst attractive due to the simplicity and cheapness of its preparation provided by the mechanochemical approach.

Curvature analysis of single layer graphene on the basis of extreme low-frequency Raman spectroscopy

Single layer graphene (SLG) sheets offer exciting optical and electronic properties, as well as excellent mechanical performance, which are desirable for countless potential applications in ultrathin optical, electronic, and mechanical devices. Typically, the mechanical properties of SLG are extrapolated from few layer graphene (FLG) systems in most existing experimental studies, despite the fact that the environmental mechanical response of SLG is quite different from FLG. Raman spectroscopy is one of the most versatile and nondestructive experimental techniques to probe graphene samples. Here, we provide direct experimental evidence for the vibrational behavior of SLG and its response to high pressure conditions (0–10 GPa) via Raman spectroscopy including the extreme low-frequency Raman region (5–250 cm–1). Artificial introduction of the curvature of the SLG sheets causes van Hove singularities within the range of Fermi energies (EF). The radius of curvature ρ can be predicted via a comparison of the shear mode and the breathing mode of SLG with the squash mode and the radial breathing mode of single wall carbon nanotubes (SWNTs). Furthermore, an additional polarization analysis further confirms similar low frequency modes of SLG and SWNTs under pressure. This direct investigation of SLG mechanical properties improves the quality of the available mechanical data, which is required for the design of new graphene-based nanocomposites and the development of electronic or mechatronic devices.

Removal of Chrysoidine Y from water by Graphene-based Nanocomposite Derivatives with Magnetic Chitosa Nanocomposite

This article describes a novel and efficient MCTS/GO nanocomposite for the accumulation and removal of a hazardous azo dye (Chrysoidine Y) from its aqueous solutions. Magnetic Chitosan /graphene oxide (MCTS/GO) nanocomposite adsorbent was prepared by wet-spinning technique, was used as accumulation and removal of Chrysoidine Y from aqueous solution. The structure and morphology of MCTS/GO nanocomposites were investigated using transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy were carried out on the MCTS/GO before the Chrysoidine Y (CY) accumulation experiments. The adsorption kinetics and isotherm studies were conducted under different conditions (pH = 3-7 and CY concentration = 100-400 mg/L) to examine the accumultion efficiency of the MCTS/GO towards CY in aqueous solution. The kinetics data of the adsorption process were analyzed using different kinetic models in order to investigate the adsorption behavior of CY on MCTS/GO. The results showed that the maximum adsorption capacity of the MCTS/GO nanocomposites towards CY can achieve up to ~700 mg/g for the adsorption at 300 mg/L CY. Kinetic data of adsorption process were found to fit pseudo-second order model as compared with pseudo-first-order model. The intraparticle diffusion model suggested that the adsorption process of MCTS/GO towards CY was dominated by the external mass transfer of CY molecules to the surface of MCTS/GO.

Nonenzymatic Electrochemical Determination of Paraoxon Ethyl in Water and Fruits by Graphene-Based NiFe Bimetallic Phosphosulfide Nanocomposite as a Superior Sensing Layer

A highly sensitive nonenzymatic electrochemical sensor is designed for stripping voltammetric determination of paraoxon ethyl (PE) as a model for nitroaromatic organophosphates (OPs). Graphene-based NiFe bimetallic phosphosulfide nanocomposite is used for the first time as a novel electrocatalytic modifier for enhancing the electrochemical signal of PE. As a consequence of the efficient π-π stacking interactions between the aromatic structure of OPs and graphene and also due to the strong electrocatalytic properties of the bimetallic phosphosulfide, PE can strongly bind to the surface of modified glassy carbon electrodes and provide a dramatically enhanced voltammetric signal in a nonenzymatic determination method. Maximum square wave voltammetric (SWV) signals were obtained when the adsorption step was completed via 5-min convection at 1000 rpm in an analyte solution with the adjusted pH of 6. The SWV signal of PE was highly linear over the range of 12.3–10,000 nmol L−1 and with the detection limit of 3.7 nmol L−1 (S/N = 3). The developed sensor shows good reproducibility (RSD = 5.2%, N = 10). The study offers a promising application for bimetallic phosphosulfide compounds for developing fast, simple, and highly sensitive nonenzymatic determination protocol for nitroaromatic OPs.

Enhanced photocatalytic degradation of methyl orange by porous graphene/ZnO nanocomposite

Degrading aquatic organic pollutants efficiently is very important but strongly relied on the design of photocatalysts. Porous graphene could increase photocatalytic performance of ZnO nanoparticles by promoting the effective charge separation of electron-hole pairs if they can be composited. Herein, porous graphene, ZnO nanoparticles and porous graphene/ZnO nanocomposite were prepared by fine tuning of partial combustion, which graphene oxide imperfectly covered by the layered Zn salt was combusted under muffle furnace within few minutes. Resulting ZnO nanoparticles (32–72 nm) are dispersed uniformly on the surface of graphene sheets, the pore sizes of porous graphene are in the range from ∼3 to ∼52 nm. The synthesized porous graphene/ZnO nanocomposite was confirmed to show enhanced efficiency under natural sunlight irradiation compared with pure ZnO nanoparticles. Using porous graphene/ZnO nanocomposite, 100% degradation of methyl orange can be achieved within 150 min. The synergetic effect of photocatalysis and adsorption is main reason for excellent MO degradation of PG/ZnO nanocomposite. This work may offer a new route to accurately prepare porous graphene-based nanocomposite and open a door of their applications.

UV Irradiated Graphene-Based Nanocomposites: Change in the Mechanical Properties by Local HarmoniX Atomic Force Microscopy Detection.

Epoxy based coatings are susceptible to ultra violet (UV) damage and their durability can be significantly reduced in outdoor environments. This paper highlights a relevant property of graphene-based nanoparticles: Graphene Nanoplatelets (GNPs) incorporated in an epoxy-based free-standing film determine a strong decrease of the mechanical damages caused by UV irradiation. The effects of UV light on the morphology and mechanical properties of the solidified nanocharged epoxy films are investigated by Atomic Force Microscopy (AFM), in the acquisition mode “HarmoniX.” Nanometric-resolved maps of the mechanical properties of the multi-phase material evidence that the incorporation of low percentages, between 0.1% and 1.0% by weight, of graphene nanoplatelets (GNPs) in the polymeric film causes a relevant enhancement in the mechanical stability of the irradiated films. The beneficial effect progressively increases with increasing GNP percentage. The paper also highlights the potentiality of AFM microscopy, in the acquisition mode “HarmoniX” for studying multiphase polymeric systems.

Experimental Investigation of Freezing and Melting Characteristics of Graphene-Based Phase Change Nanocomposite for Cold Thermal Energy Storage Applications

In the present work, the freezing and melting characteristics of water seeded with chemically functionalized graphene nanoplatelets in a vertical cylindrical capsule were experimentally studied. The volume percentage of functionalized graphene nanoplatelets varied from 0.1% to 0.5% with an interval of 0.1%. The stability of the synthesized samples was measured using zeta potential analyzer. The thermal conductivity of the nanocomposite samples was experimentally measured using the transient hot wire method. A ~24% (maximum) increase in the thermal conductivity was observed for the 0.5% volume percentage in the liquid state, while a ~53% enhancement was observed in the solid state. The freezing and melting behavior of water dispersed with graphene nanoplatelets was assessed using a cylindrical stainless steel capsule in a constant temperature bath. The bath temperatures considered for studying the freezing characteristics were −6 °C and −10 °C, while to study the melting characteristics the bath temperature was set as 31 °C and 36 °C. The freezing and melting time decreased for all the test conditions when the volume percentage of GnP increased. The freezing rate was enhanced by ~43% and ~32% for the bath temperatures of −6 °C and −10 °C, respectively, at 0.5 vol % of graphene loading. The melting rate was enhanced by ~42% and ~63% for the bath temperatures of 31 °C and 36 °C, respectively, at 0.5 vol % of graphene loading.

Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites

Abstract Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.

Graphene-Based Nanocomposites for Neural Tissue Engineering.

Graphene has made significant contributions to neural tissue engineering due to its electrical conductivity, biocompatibility, mechanical strength, and high surface area. However, it demonstrates a lack of biological and chemical cues. Also, it may cause potential damage to the host body, limiting its achievement of efficient construction of neural tissues. Recently, there has been an increasing number of studies showing that combining graphene with other materials to form nano-composites can provide exceptional platforms for both stimulating neural stem cell adhesion, proliferation, differentiation and neural regeneration. This suggests that graphene nanocomposites are greatly beneficial in neural regenerative medicine. In this mini review, we will discuss the application of graphene nanocomposites in neural tissue engineering and their limitations, through their effect on neural stem cell differentiation and constructs for neural regeneration.