Incorporation Of Graphene Oxide Research Articles

Tribological and corrosive properties examination of graphene oxide enriched electroless Ni[sbnd]P[sbnd]W composite coatings

This study focused on the mechanical, tribological, and corrosion behavior of graphene oxide (GO) reinforced NiPW composite coatings deposited by the electroless route. After deposition, all samples were analyzed using X-ray diffraction, field emission scanning electron microscope, scanning electron microscope, and energy dispersive spectroscopy methods. Hardness, tribological, and electrochemical tests of coatings were performed. The results demonstrated that the incorporation of GO effectively reduced friction, improved wear resistance, and enhanced corrosion resistance compared to NiPW coating. Among the tested concentrations, the NiPW/GO composite with 100 mg/L GO exhibited the lowest coefficient of friction as an average of 0.27 μ and the lowest corrosion potential value as Ecorr = −0.307 V.

Molecular dynamics study of temperature and defects on mechanical properties of Gr(GO)/C-S-H composites

In this paper, the effects of temperature and different defect types on the interfacial properties, kinetic properties and mechanical properties of Gr(GO)/C-S-H composites were investigated by molecular dynamics. It is shown that the incorporation of graphene (Gr) and graphene oxide (GO) improves the mechanical properties of the calcium silicate hydrate (C-S-H) model to varying degrees. The presence of defects at different temperatures affects the ordering of oxygen (Ow) in water in the proximal range of interlayer Ca ions and can effectively influence the spatial correlation between interlayer Ca ions and oxygen (Oc) in functional groups. The bond lengths of some Caw-Oc at different temperatures can be modulated by defects, thus affecting the interaction between calcium ions and graphene oxide. Compared with Gr/GO and C-S-H composites in perfect state, the incorporation of defects slows down the rate of C atoms, which can effectively enhance the interfacial connection. At temperatures of 100K-300 K, the effect of defect type on Gr/GO and C-S-H composites is small and the mobility of H atoms did not change significantly. Whereas, at high temperatures 400 K and 500 K, the presence of defects gives higher mobility of H atoms, which affects the properties of the composites. The tensile strength (compressive strength) and Young's modulus of Gr(GO)/C-S-H composites at perfect and different defect types basically show a decreasing trend with increasing temperature. The system structure changes during the relaxation process because of the different defect types and Gr (GO), which make the initial structure different, and thus the mechanical properties change.

Synergistic performance of polyethersulfone membranes embedded with graphene oxide‐zinc oxide nanocomposites for efficient heavy metal and dye removal with strong antibacterial properties

AbstractWater pollution caused by heavy metal ions (HMI) and dyes is a global issue challenging current solutions. Membrane filtration shows promise, yet faces limitations like fouling and low flux. This study proposes a new membrane by incorporating graphene oxide zinc oxide (GO‐ZnO) nanocomposites into a polyethersulfone (PES) matrix to overcome these challenges. The synthesized membrane exhibits strong antimicrobial activity, crucial for water treatment, and high efficiency in removing HMIs (Cu2+ and Ni2+) and dyes (BB9 and EBT) from water samples and industrial wastewater. Characterization via FTIR and FESEM confirms its chemical composition and morphology, while contact angle measurements assess its hydrophilicity. Mechanical strength tests ensure durability. Overall, the membrane demonstrates exceptional antimicrobial activity, pollutant removal efficiency, and mechanical robustness, highlighting the potential of integrating GO‐ZnO nanoparticles into PES membranes for water treatment.Highlights Synthesis of innovative PES membrane embedded with GO‐ZnO for durable and fast energy‐saving filtration. Thorough Membrane Characterization and its various applications with mechanisms. Efficient Heavy Metal and Dye Removal, Inherent Antibacterial Prowess.

Effect of Graphene Oxide Incorporation on the Strength of Denture Repair Resin

To evaluate the effect of incorporating graphene oxide nanoparticles (GO NPs) and graphene sheets on the flexural strength of an auto-polymerized (AP) acrylic resin-repaired denture. 60 heat-activated (HA) resin specimens were fabricated and randomly divided into 6 groups (n = 10). The specimens in Group I were kept intact. 50 specimens were cut into two parts with a 45-degree bevel. Group II specimens were repaired with AP resin and Group III specimens were repaired with HA resin. In the repair of Group IV, Group V, and Group VI specimens, 1%, 2% GO NPs, and graphene sheets were added to AP resin, respectively. A 3-point bending test with a universal test device measured the flexural strength. Statistical analyses of the results were performed with the Kruskal Wallis H-test. (α = 0.05) The flexural strength of Group I (130.05 ± 20.20 MPa) was the highest among all groups. The flexural strength of Group IV (67.49 ± 12.70 MPa) was significantly higher than Group V (50.87 ± 15.02 MPa) and Group VI (44.77 ± 10.70 MPa). The lowest strength value was obtained in Group VI. Adding 1% GO NPs to AP acrylic resins increases flexural strength. However, the increase in nanoparticle concentration and the addition of graphene sheets negatively affect strength.

Synergistic electrochemical and optical properties of a UVC class quaternary nanocomposite incorporating graphene oxide and samarium chromium oxide perovskite

This research presents a comprehensive investigation into a novel quaternary nanocomposite comprising graphene oxide (GO), samarium chromium oxide perovskite (SmCrO3), silicon dioxide (SiO2), and tin dioxide (SnO2). The nanocomposite was synthesized using a modified Stöber method. In order to assess its potential applications in supercapacitors and UVC devices, an extensive analysis of its electrochemical and optical properties was conducted. The crystal structure and phase identification were analyzed using X-ray diffraction (XRD) and Rietveld refinement with X'pert HighScore Plus software, confirming the successful formation of the nanocomposite. Scanning electron microscopy (SEM) provided valuable insights into the structural morphology, while energy dispersive X-ray spectroscopy (EDS) confirmed the presence of constituent elements. Fourier transform infrared (FTIR) analysis and Raman Spectroscopy elucidated the functional groups and chemical bonds, confirming the successful synthesis of the nanocomposite. UV–Vis spectroscopy and photoluminescence (PL) spectroscopy revealed its strong UV radiation absorption and intensified fluorescence properties and confirming the band gap of SmCrO3 and GO/SmCrO3/SiO2/SnO2 quaternary nanocomposite as ∼5.4 eV and 4.84 eV respectively. The potential of nanocomposite potential as a supercapacitor material was evaluated through cyclic voltammetry (CV) measurements and electrochemical impedance spectroscopy (EIS) analyses. Remarkably, the specific capacitance of the nanocomposite reached 253.75 Fg−1 at a scan rate of 10 mVs−1, and electrochemical surface area of 507 cm2, highlighting its exceptional charge storage capability and promising prospects for high-performance energy storage devices. This comprehensive study addresses a significant knowledge gap, providing a profound understanding of the electrochemical and optical behavior of the quaternary nanocomposite. The observed exceptional results underscore its suitability for supercapacitor applications and expected favorable material for UVC device technologies.

Rheological study of hybrid aqueous suspension of TEMPO-oxidized cellulose nanofibrils and graphene oxide

The incorporation of graphene oxide (GO) into a nanocellulose matrix has attracted considerable attention due to the unique advantages of both components. This study focuses on investigating the viscoelastic and flow properties of hybrid aqueous suspensions (2.00 w/v%), composed of TEMPO-oxidized cellulose nanofibrils (TOCNF) and GO at different TOCNF/GO weight ratios. To adjust the elastic properties of the hybrid suspensions, calcium ions are introduced, varying the concentration systematically to study their effects on the hybrid network structure. All blends exhibit shear-thinning behaviour and demonstrate elastic, gel-like properties. Notably, in the absence of calcium ions, the enhancement of elastic properties is more pronounced at higher GO fractions. Conversely, with the introduction of calcium ions, the enhancement of elastic properties becomes particularly important at higher TOCNF fractions. For the quantitative evaluation of these enhancements, we employ the logarithmic mixing rule. Significant positive deviations from the predictions of the logarithmic mixing rule are ascribed to the complex, concentration-dependent arrangement of cellulose nanofibrils and GO liquid crystals in the aqueous suspension, coupled with ionic crosslinking induced by calcium ions. The study aims to contribute to the understanding of the rheological behaviour of the TOCNF/GO hydrogel, showing potential advancements in various applications.Graphical abstract

Microstructure and Biocompatibility of Graphene Oxide/BCZT Composite Ceramics via Fast Hot-Pressed Sintering

Improving fracture toughness, electrical conductivity, and biocompatibility has consistently presented challenges in the development of artificial bone replacement materials. This paper presents a new strategy for creating high-performance, multifunctional composite ceramic materials by doping graphene oxide (GO), which is known to induce osteoblast differentiation and enhance cell adhesion and proliferation into barium calcium zirconate titanate (BCZT) ceramics that already exhibit good mechanical properties, piezoelectric effects, and low cytotoxicity. Using fast hot-pressed sintering under vacuum conditions, (1 − x)(Ba0.85Ca0.15Zr0.1Ti0.9)O3−xGO (0.2 mol% ≤ x ≤ 0.5 mol%) composite piezoelectric ceramics were successfully synthesized. Experimental results revealed that these composite ceramics exhibited high piezoelectric properties (d33 = 18 pC/N, kp = 62%) and microhardness (173.76 HV0.5), meeting the standards for artificial bone substitutes. Furthermore, the incorporation of graphene oxide significantly reduced the water contact angle and enhanced their wettability. Cell viability tests using Cell Counting Kit-8, alkaline phosphatase staining, and DAPI staining demonstrated that the GO/BCZT composite ceramics were non-cytotoxic and effectively promoted cell proliferation and growth, indicating excellent biocompatibility. Consequently, with their superior mechanical properties, piezoelectric performance, and biocompatibility, GO/BCZT composite ceramics show extensive potential for application in bone defect repair.

GO and surfactant assisted regulation of polyamide nanofiltration membranes for improved separation performance

Fabricating nanofiltration membranes with high water permeance and selectivity by tailoring the structure and morphology is crucial to efficient water purification. In this work, the fabrication of thin film nanocomposite (TFN) nanofiltration membranes by combining two methods, the surfactant-assembly interfacial polymerization (SARIP) and the addition of graphene oxide (GO) or ionic liquid functionalized graphene oxide (GO-IL) for the preparation of the selective PA layer on a novel porous substrate is reported. For the preparation of the porous substrate, mechanically robust, aromatic polyethers containing polar pyridine units (PDSPP) were chosen targeting to improved hydrophilicity and thus enhanced water permeability. The anionic sodium dodecyl sulfate (SDS) surfactant was used to regulate the interfacial polymerization thereby enabling the formation of dense PA layers with high cross-linking degree and consequently high salt rejections. On the other hand, the addition of GO/GO-IL nanosheets could impart hydrophilicity and antifouling properties. The novel porous PDSPP substrate was selected for the fabrication of TFN membranes due to its improved water permeability and superior salt rejection and increased hydrophilicity compared to commercial PSf substrate. The detailed study of the fabricated TFN membranes by ATR-FT-IR, SEM, AFM, XPS, contact angle measurements revealed the formation of polyamide selective layers with rougher surfaces, increased hydrophilicity and high cross-linking degrees (from 44 % to 94 %), resulted from the synergistic effect of SDS and GO incorporation. Moreover, the prepared TFN membranes exhibited high salt rejections while maintaining a moderate water permeability. In particular, the membrane containing the neat GO (TFNGO50) displayed excellent Na2SO4 and MgSO4 rejections (98.8 % and 99.5 %, respectively) while the NaCl rejection was 47.0 % and a water permeability value of 4.2 L m-2h−1 bar−1. The divalent salt rejections were among the highest values reported in the literature in comparison with commercial NF membranes and TFN membranes containing GO/functionalized GO. When GO-IL nanosheets were embedded in the PA layer, the water permeability was slightly improved while the salt rejections were significantly reduced compared to TFNGO50. Lastly, the incorporation of GO enhanced the anti-fouling properties of the prepared membranes due to increased hydrophilicity of the PA surface.

Evaluation of physical and mechanical properties of graphene oxide reinforced epoxy/Kevlar hybrid composites

Graphene is a miracle material with low density, excellent mechanical strength, electrical conductivity, molecular barrier properties and many other remarkable properties. Hence, recent research has been more focused on delving into various application areas of graphene. In this study, the effects of graphene oxide (GO) on the mechanical properties of composites based on epoxy resin and Kevlar fibers were investigated. The composites were fabricated by incorporating varying concentrations (1 %, 3 %, 5 %, 10 %, and 16 %) of graphene oxide (GO) into an epoxy matrix. The matrix was reinforced by two different wt.% (12.5 % and 25 %) of Kevlar fibers (KF). The hybrid composites were manufactured by hand lay-up process in a silicon mold at room temperature. Mechanical characterizations such as flexural, impact and hardness test exhibited an enhancement of the mechanical properties of the composites. Moreover, the measured density showed a significant reduction in density with increasing wt.% of GO. As a result, it was possible to fabricate a composite with a significant increase of specific flexural strength and specific flexural modulus. A microstructural analysis of the composites was performed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX). From the SEM images, it was revealed that the interphase bonding of the GO particles with Kevlar fibers and matrix was strong, thereby resulting in improved mechanical performance. It was observed that 5 wt% GO incorporation along with 25 wt% KF showed improved flexural strength, hardness and impact strength than that of sample fabricated only with Kevlar.

Construction of three-dimensional polyethyleneimine incorporated graphene oxide aerogels as high-capacity electrode for enhanced uranium(VI) electrosorption performance

Electrosorption technique is paid more attention in recovery of uranium(VI) due to its low energy consumption, green process and easy regeneration, but still is hindered by the limited accessible active sites on the electrode material, poor surface wettability and inherent ion exclusion effects. Herein, novel there dimensional porous polyethyleneimine/graphene oxide aerogel (PEI/GOA) electrode was constructed by incorporating polyethyleneimine into graphene oxide and using chitosan as binder for uranium(VI) electrosorption. The synthesized PEI/GOA had a stable three-dimensional porous structure, high specific capacitance (54.06F/G) and good charge–discharge stability. The electrosorption process of uranium(VI) by PEI/GOA electrode was affected by applied voltage and pH, fitted by the pesuo-second-order kinetics and Langmuir model. The maximum theoretical electrosorption capacity of uranium(VI) by PEI/GOA electrode at − 1.2 V was 419.71 mg/g, which was 2.2 times higher than that of pure graphene oxide electrode. PEI/GOA electrode exhibited less than 20 % loss after five cycles using 0.1 M NaHCO3 as the eluent. The efficient U(VI) electrosorption by PEI/GOA electrode was not only attributed to the formation of the electric double layer, but also due to the interaction and synergy of the –NH2, –CONH- and –OH on the PEI/GOA electrode. This research offers a new approach for the efficient removal of uranium (VI) from uranium-containing wastewater.

Dual Stimulus Responsive GO-Modified Tb-MOF toward a Smart Coating for Corrosion Detection.

Smart-sensing coatings that exhibit multistimulus response, rapid indication, and reusability are in urgent need to effectively enhance the practicability of coatings while accurately detecting metal corrosion. In this work, a reusable corrosion self-reporting coating with multiple pH and Fe3+ stimulus responses was first constructed by the integration of a composite fluorescent probe into the resin matrix. This composite sensor was constructed by combining a lanthanide metal-organic framework (Ln-MOF) based on terbium and trimeric acid (H3BTC) with graphene oxide (GO) nanosheets (GO@Tb-BTC). The incorporation of GO formed a sea-urchin-like structure, thereby increasing the specific surface area and active sites of the probe. The coatings were characterized by using electrochemical impedance spectroscopy (EIS), visual observation, and fluorescence spectrophotometry. The surface morphology, wettability, and adhesion of the coating samples were analyzed using SEM, XPS, hydrostatic contact angle test, and an adhesion test. EIS measurements in 3.5 wt % NaCl solution for 72 h demonstrated the superior corrosion protection performance of the 0.3 wt %/GO@Tb-BTC/WEP coating compared to blank coating, with the charge-transfer resistance reaching 4.33 × 107 Ω·cm2, which was 9.5 times higher than that of the pure coating. The bright green fluorescence of GO@Tb-BTC/WEP coating exhibited a turn-off response when there was an excess of OH-/H+, but it demonstrated a reversible turn-on fluorescence when the ambient pH returned to neutral. Furthermore, such Fe3+-triggered fluorescence quenching responded to concentrations as low as 1 × 10-6 M. The fluorescence quenching rate of both intact and damaged coatings surpassed that of visual and EIS detection methods. Significantly, the fluorescence in scratches was effectively quenched within 25 min using 0.3 wt %/GO@Tb-BTC/WPU coating for visual observation. GO@Tb-BTC demonstrated exceptional corrosion self-reporting capabilities in both epoxy and polyurethane systems, making it a versatile option beyond single-coating applications.

Influence of graphene oxide additives on the NF separation of triazine-based H2S scavenging compounds using advanced membrane technology

This work proposes an innovative approach for the membrane separation of spent and unspent H2S scavengers (SUS) derived from the application of MEA-triazine in offshore oil and gas production. Modified nanofiltration membranes were fabricated by incorporating graphene oxide (GO) and polyvinyl alcohol (PVA) into a thin film composite (TFC) to obtain a thin film nanocomposite (TFN) with enhanced permeability. In addition, various immobilization strategies for GO were investigated. The performance of the membranes and the effect of the GO loading were evaluated in terms of permeability, fouling propensity, and rejection of key components of the SUS, i.e., MEA-triazine (unspent scavenger), dithiazine (spent scavenger), and monoethanolamine, operating on a sample of SUS wastewater obtained from an offshore oil and gas platform. Various characterization techniques, such as contact angle, FTIR, XRD, SEM, TGA, and AFM, were employed to evaluate the structure, composition, and hydrophilicity of the membrane. The results show a remarkable increase in permeability (from 0.22 Lm-2 h−1 bar−1 for the TFC to 5.8 Lm-2 h−1 bar−1 for the TFN membranes), due to the enhanced hydrophilicity from GO incorporation. The strong interfacial interaction between GO and PVA within the TFN membrane results in negligible nanofiller leaching. The incorporation of GO moderately increases the rejection of the unspent scavenger (63%–73%, 62%–79%, 62%–80%, and 68%–76%), while drastically increasing the rejection of the spent scavenger, which is approximately null for the TFC membrane without GO and increases up to 58% in the TFN membrane with GO. Therefore, while the proposed membranes cannot be used for the selective separation of the unspent form the spent scavenger, they can achieve substantial recovery of all the key components contained in the SUS to avoid their discharge into the sea.

Synthesis of composite membranes modified with graphene oxide and polyethylene glycol for the removal of emerging contaminants from water

Graphene oxide (GO) incorporation of the polymer matrix of membranes can provide properties such as great durability, resistance, and reduction of fouling. In turn, polyethylene glycol (PEG) is a polymer capable of increasing the porosity and flow of membranes. The study aimed to analyze the synthesis of composite membrane polysulfone (PSF), GO and PEG, to separate caffeine, diclofenac sodium, and amoxicillin dispersed in water. It observed an increase in roughness through the incorporation of GO and its reduction with the addition of PEG. Membrane permeability increased from 0.61 L m-2 h-1 bar-1 to 4.54 L m-2 h-1 bar-1 after the addition of GO and PEG. The water permeance of the synthesized membranes reached 37.81 L m-2 h-1 bar-1. It is concluded that the structure and porosity, as well as the rejection of contaminants, were directly influenced by the incorporation of materials added to the membranes. The charge of GO contributed to structural and mechanical improvements of the membranes, reaching rejections of up to 80.61% of caffeine, 66.03% of diclofenac sodium, and 87.33% of amoxicillin with the membrane containing 1.5% of GO, being thus, it is considered promising for applications in water contaminated by emerging contaminants. The study brings real contributions to the area of membranes by developing an improved material, especially as it presents a high rejection of emerging contaminants that are still little studied.

Compatibility of Molybdenum Disulfide and Magnesium Fluorinated Alkoxyaluminate Electrolytes in Rechargeable Mg Batteries

Molybdenum disulfide (MoS2)‐based cathodes have exhibited good electrochemical reactions in all phenyl complex (APC) electrolytes. However, APC electrolytes are highly corrosive and susceptible to oxidation. Alternatively, magnesium fluorinated alkoxyaluminate electrolyte (Mg[Al(HFIP)4]2) is a pioneering chloride‐free electrolyte with remarkable electrochemical activity in rechargeable Mg batteries (RMBs). This study aims to investigate the compatibility of various MoS2 nanomaterials with Mg[Al(HFIP)4]2 in RMBs. Seven MoS2 nanomaterials were synthesized under different hydro/solvothermal conditions and evaluated as cathode materials in RMBs. The results revealed that the electrochemical activity of the as‐synthesized MoS2 in RMBs significantly varied and MoS2 with high content of 1T‐phase (M5) exhibited the best specific capacity of ca. 35 mAh g−1. Heteroatom doping, graphene oxide (GO) incorporation, and dual‐salt electrolytes were employed to enhance the electrochemical performance of M5. The electrochemical tests showed that all doped‐MoS2 and GO‐MoS2 delivered poor specific capacities (< 20 mAh g−1), properly due to the disorder of the cathode material and the entrapment of Mg2+ ions. In contrast, dual‐salt electrolytes (0.3 M Mg[Al(HFIP)4]2/0.3 M LiCl) improved the initial specific capacity by 242%. This is attributed to the preferential intercalation of Li+ ions that reduces the diffusion energy barrier and facilitates the intercalation of Mg+2 ions.

Promoting Thermal Conductivity of Alumina-Based Composite Materials by Systematically Incorporating Modified Graphene Oxide

Small amounts of thermally conductive graphene oxide (GO) and modified GO are systematically introduced as a second filler to thermal interface materials (TIMs) consisting of alumina (Al2O3) particles and polydimethylsiloxane (PDMS). The surface of GO is covalently linked with an organic moiety, octadecylamine (ODA), to significantly improve the miscibility and dispersity of GO across the TIM matrix. Subsequently, two series of PDMS-Al2O3 composite TIMs are manufactured as a function of GO and ODA-GO content (0.25 wt%–2.5 wt%) to understand the effect of these second additives. The incorporation of GO into the Al2O3-PDMS composite materials generally increases the thermal conductivity (TC), ranging from 18% to 29%. Conversely, the use of ODA-GO further enhances the overall performance of TIMs (22–54%) by facilitating the dispersion degree of GO across the composite matrix. The great improvement in TC is presumably related to the formation of conductive pathways by uniformly integrating 2D-type GO flakes across spherical Al2O3 particle networks. The ability to simply regulate the polarity of the thermally conductive second filler can provide an idea for designing cost-effective and practical TIM-2-type pads that can be commercially applicable in between an integrated heat spreader and a heat sink.

Incorporating GO in PI matrix to advance nanocomposite coating: An enhancing strategy to prevent corrosion

Abstract This research endeavors to advance the anti-corrosive characteristics, mainly the physico-mechanical properties, by incorporating graphene oxide (GO) into a polyimide (PI) matrix. So, a nanocomposite coating is fabricated for an aluminum alloy substrate. Results reveal that the coating was uniformly dispersed across the surface signifying that the inclusion of GO increased the PI dispersion. The π–π stacking interactions between the aromatic rings of PI and GO contribute to their stability and improved anticorrosive properties. The incorporation of GO to PI films significantly enhances hydrophobicity, as evidenced by the increased contact angles. Assessing the corrosion resistance of the coating in a 3.5 wt% NaCl solution through electrochemical impedance spectroscopy and potentio-dynamic polarization establishes a prominent correlation between the percentage of GO and the anticorrosion efficiency of the composite coating. Precisely, the nanocomposite coating containing 5 wt% GO exhibits an impressive impedance modulus value of 107, and the corrosion current density (I cor) is drastically reduced by over three orders of magnitude, reaching 4.8 × 10−9 A cm−2, as indicated by the polarization curve. Also, prolonged immersion tests confirm the exceptional protective ability of the S5 coating (5 wt% GO), effectively shielding the metal for up to 100 h. After conducting diagnostic measurements, the hybrid nanocomposites of GO/PI examined in this study showcased their effectiveness as inhibitors in anticorrosive coatings. These composites played a vital role to hinder the oxidation of underlying aluminum alloy when exposed to oxidizing chemicals, water, or air, thereby extending the protective duration.

Control of Cell Adhesion and Growth on Polysaccharide-Based Multilayer Coatings by Incorporation of Graphene Oxide

Controlling cell adhesion, viability, and proliferation on solid surfaces is critical for the successful implantation and proper functioning of temporary and permanent medical devices. While, with temporary or removable implants as well as surgical instruments, even slight cellular adhesion leads to an increased risk of secondary infections, bleeding and other complications, good cellular adhesion and viability are essential for the rapid healing and successful integration of permanent implants. This work was motivated by the growing interest in the construction of biocompatible and biodegradable coatings for the biofunctionalization of medical devices. Polysaccharide-based coatings are well known for their biocompatibility, but they are non-cell-adhesive, which hinders their application as implant coatings. In this study, we demonstrate that the incorporation of one or more graphene oxide layers in hyaluronic acid/chitosan multilayers is one avenue to regulate the degree of unspecific adhesion and growth of different cells (human umbilical vein endothelial cells, HUVEC, and mouse embryonic fibroblasts, 3T3). Furthermore, we demonstrate that this approach allows cell adhesion to be regulated across the entire range between completely prevented and highly promoted cell adhesion without introducing systemic cytotoxicity. These findings may contribute to the establishment of a new approach to adapt medical devices to cells and tissues.

Arc erosion resistance of Al2O3–Cu/35Mo composites reinforced by trace graphene oxide

In this study, Al2O3–Cu/35Mo composites were prepared by rapid hot-press sintering-internal oxidation method, and the materials were modified by adding trace amounts of graphene oxide (GO). The results show that the relative densities of the composites are above 99%, the γ-Al2O3 generated by internal oxidation is diffusely distributed on the copper matrix. The incorporation of GO produced a small number of hard MoC particles at the interface, which facilitated the interfacial bonding of the composites. In the 30 V DC, 10–30 A electrical contact test, the anode mass of the composites increases, while the cathode mass decreases. And GO reduces the total mass loss of the electric contact by 63.6%, 38.9%, 51.3% and 20.9%, respectively. A comparison of the electrical contact properties of the two materials showed that the addition of GO dispersed the concentrated erosion of the arc. At 10 A and 30 A, the arc energy is reduced by 75.5% and 12.5%, respectively. With the gradual increase in electric current, GO makes the Al2O3–Cu/35Mo composites more stable during the electric contact process, improves the anti-welding ability of the contact and reduces contact resistance.

Evaluation of the mechanical properties and degradation behavior of chitosan-PVA-graphene oxide nanocomposite scaffolds in vitro

ObjectivesChitosan (CTS) has been a popular option for scaffold fabrication because of its biocompatibility, biodegradability, antimicrobial and nonimmunogenic effects. However, it is of limited function, due to its low mechanical strength and its solubility in acidified media. These limitations could be overcome by its blending with PVA and incorporation with bioactive materials to improve its mechanical properties and tissue regeneration capability. MethodsCarbon based nanomaterials, such as graphene oxide (GO) incorporated with CTS/PVA blend to improve composite-scaffold stability. GO nanoparticles were chemically prepared and fully characterized. Different concentrations of both CTS and nano-GO were used for the fabrication of CTS/PVA/GO nanocomposite films through the solvent-casting method. The mechanical properties, thermal stability biodegradation, and swelling of the nanocomposite films were evaluated after characterization by XRD, FTIR and SEM, to detect the effect of GO incorporation in the scaffold to select the suitable dental application. ResultsA better performance was observed in thermal stability, biodegradation, and water resistance after GO addition into CTS/PVA scaffolds. Regarding mechanical properties, groups were assessed by Kruskal Wallis test afterward Dunn’s post hoc test. There was no significant difference in tensile strength between the nanocomposite films of CTS (2%) and CTS (3%). The tensile strength decreased after addition of nano-GO at different concentrations. The elastic modulus significantly increased when (1%) GO was added into the 1CTS (2%):1PVA. ConclusionsCTS/PVA/GO nanocomposite can be used in dental hard tissue engineering, as the incorporation of GO into the CTS/PVA polymer blend improves its properties which is regarded as the critical concentrations of CTS and GO.

Green and Heavy-Duty Anticorrosion Coatings: Waterborne Epoxy Thermoset Composites Modified through Variation of Zinc Dust Loading and Incorporation of Amine-Capped Aniline Trimer and Graphene Oxide.

In this study, an array of environmentally friendly and heavy-duty anticorrosion composite coatings were prepared. The synthesis involved amine-capped aniline trimer (ACAT) produced by an oxidative coupling reaction and graphene oxide (GO) prepared based on Hummer's method, and later, the waterborne epoxy thermoset composite (WETC) coatings were prepared by thermal ring-opening polymerization of EP 147w, a commercial waterborne epoxy resin, in the presence of ACAT and/or GO with zinc dust (ZD). A synergistic effect was observed by replacing a significant amount of the ZD loading in the WETC by simultaneously incorporating a small amount of ACAT and GO. The electrochemical corrosion measurements of the as-prepared WETC coatings indicated that incorporating 5% w/w ACAT or 0.5% w/w GO separately replaced approximately 30% w/w or 15% w/w of the ZD, respectively. Moreover, the WETC coatings containing 5% w/w ACAT and 0.5% w/w GO simultaneously were found to replace 45% w/w of the ZD. A salt spray test based on ASTM B-117 also showed a consistent trend with the electrochemical results. Incorporating small amounts of ACAT and GO in WETC coatings instead of ZD not only maintains the anticorrosion performance but also enhances adhesion and abrasion resistance, as demonstrated by the adhesion and abrasion tests.