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Wyniki wyszukiwania dla: GRAPHENE DERIVATIVES TRIBOLOGY
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Graphene and Its Derivatives for Energy Storage
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Fully scalable one-pot method for the production of phosphonic graphene derivatives
PublikacjaGraphene oxide was functionalized with simultaneous reduction to produce phosphonated reduced graphene oxide in a novel, fully scalable, one-pot method. The phosphonic derivative of graphene was obtained through the reaction of graphene oxide with phosphorus trichloride in water. The newly synthesized reduced graphene oxide derivative was fully characterized by using spectroscopic methods along with thermal analysis. The morphology...
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Nanoconjugates of graphene oxide derivatives and meso-tetraphenylporphyrin: a new avenue for anticancer photodynamic therapies – Cell-on-a-Chip analysis
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Graphene Reinforced Phenolic Foams
PublikacjaPhenolic foams (PF) belong to the polymeric materials, which are very attractive from the point of many possible applications such as insulation or fire protection materials. This chapter attempts to explain the influence of graphene and graphene derivatives on the phenolic foams. This work briefly presents different graphene nanoparticles introduced to the phenolic foams matrix, in terms of impact on the thermal, mechanical, and...
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Morphology, Mechanical and Thermal Properties of Thermoplastic Polyurethane Containing Reduced Graphene Oxide and Graphene Nanoplatelets
PublikacjaPolyurethane/graphene nanocomposites were synthesized using commercial thermoplastic polyurethane (TPU, Apilon 52DE55), and two types of graphene derivatives: graphene nanoplatelets (GNP) and reduced graphene oxide (RGO). Fourier Transformation Infrared Spectroscopy Fourier Transformation Infrared Spectroscopy (FTIR) spectroscopy, TEM, and SEM microscopy and XRD techniques were used to chemically and structurally characterize GNP...
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Towards large-scale application of nanoporous materials in membranes for separation of energy-relevant gas mixtures
PublikacjaMembranes containing nanoporous materials (such as zeolites, metal–organic materials and 2D materials such as graphene derivatives) may allow more efficient separation of gas mixtures relevant to emerging energy technologies. For example, such membranes could be applied in the separation of gases containing mixtures of carbon dioxide (CO2) and hydrogen (H2). However, these membranes are currently at a relatively low technology...
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Graphene-based Silicone rubber Nanocomposites: Preparation, Characterization, and Properties
PublikacjaThis study aims to understand better the mechanical, thermal, and tribological behavior of silicone rubber nanocomposites. Graphite, exfoliated graphite, reduced graphene oxide, ionic liquid modified graphene oxide, silane-modified graphene oxide, fumed silica, and other fillers were used in this study. Adding graphene-based fillers to the silicone rubber matrix substantially improves the nanocomposite's mechanical, thermal, and...
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Carbon Nanomaterials in Seed Priming: Current Possibilities
PublikacjaThe prevailing agricultural system has become deeply ingrained and insufficient due to outdated practices inherited from the Green Revolution, necessitating innovative approaches for sustainable agricultural development. Nanomaterials possess the potential to significantly improve the efficient utilization of resources while simultaneously encouraging sustainability. Among these, carbonaceous nanomaterials have found diverse applications...
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GRAPHENE IN GAS CHEMIRESISTORS
PublikacjaGraphene has a range of unique physical properties which could be exploited in gas sensing. Every atom of graphene may be considered as a surface atom, able to interact even with single molecule of the target gas or vapour species resulting in the ultrasensitive sensor response. In this paper the potential of graphene as a nanomaterial for fabricating chemiresistors was described. Recent development in graphene sensors was considered...
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Tribology of the cartilage cells in the intelligent bioreactor
PublikacjaW badaniach analityczno-numerycznych wyznaczone zostały pola prędkości przepływu lepkosprężystej, odżywczej nienewtonowskiej cieczy biologicznej, a także powstające siły tarcia w trakcie hodowli w warstwie granicznej wokoło powierzchni hodowanych komórek w bioreaktorach, stawach człowieka oraz w szczelinach mikrołożysk. Dodatkowo rozpatrywane będą przepływy potencjalne płynu stawowego z jamy stawowej, które odżywiają chrząstkę...
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Tribology of stochastic phenomena on the hard tissue.
PublikacjaPraca przedstawia model matematyczny zjawisk tribologicznych podczas hodowli tkanek twardych, w tym chrząstek stawowych. Uwzględnia się chropowatości powierzchni hodowanych chrząstek. Problem tribologiczny uzewnętrzniony został koniecznością sterowania wartościami sił tarcia jakie powstają w cienkiej warstewce przyściennej opływanej tkanki cieczą biologiczną w trakcie hodowli. Taki model matematyczny nie był do tej pory rozpatrywany.
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Tribology of bone tissue culture in bioreactor.
PublikacjaOpracowano system tribologiczny powstających sił tarcia w bioreaktorze. Pomimo, że wartości sił tarcia osiągają wartości poniżej 0,1 N to mają one decydujący wpływ na wartość porostu tkanki. Mechanika opływu tkanki cieczą o właściwościach biologicznych nienewtonowskich oraz hydrodynamiczna teoria opływu warstwy przyściennej jest bazą wyznaczania parametrów trybologicznychniniejszej pracy.
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Graphene oxide, reduced graphene oxide and composite thin films NO2 sensing properties
PublikacjaA graphene oxide (GO), reduced graphene oxide (RGO) and poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO composite) gas sensors were successfully fabricated using an electrodeposition method. The electrodeposition was carried out in aqueous GO dispersions. To obtain RGO and PEDOT-RGO, the electrochemical reduction of GO and PEDOT-GO was carried out in 0.1 M KCl at a constant potential of −0.85 V. The GO, RGO and PEDOT-RGO...
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Graphene Production and Biomedical Applications: A Review
PublikacjaGraphene is a two-dimensional nanomaterial composed of carbon atoms with sp2 hybrid orbitals. Both graphene and graphene-based composite have gained broad interest among researchers because of their outstanding physiochemical, mechanical, and biological properties. Graphene production techniques are divided into top-down and bottom-up synthesis methods, of which chemical vapor deposition (CVD) is the most popular. The biomedical...
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Graphene oxide, reduced graphene oxide and composite thin films NO2 sensing properties
PublikacjaA graphene oxide (GO), reduced graphene oxide (RGO) and poly(3,4-ethylenedioxytiophene)- reduced graphene oxide (PEDOT-RGO composite) gas sensors were successfully fabricated using an electrodeposition method. The electrodeposition was carried out in aqueous GO dispersions. In order to obtain RGO and PEDOT-RGO, the electrochemical reduction of GO and PEDOT-GO was carried out in 0.1 M KCl at constant potential of −0.85 V. The GO, RGO...
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Facile synthesis and characterization of graphene and N-doped graphene by CVD method from liquid precursors for promising electrode materials
PublikacjaIn this study, high-quality and few-layered graphene was synthesized using the chemical vapor deposition (CVD) method from liquid sources. Two different liquid carbon sources, pyridine, and benzene, were used and deposited on nickel foam under heat conditions using a bubbler in a quartz tube. X-ray diffraction (XRD) and Raman analysis confirmed the crystalline properties of graphene and N-doped graphene, demonstrating the high...
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Optimization of Graphene Oxide Synthesis and Its Reduction
PublikacjaIn this article, we present the review of the chemical methods of synthesis of graphene oxide and its reduction in order to obtain the so-called reduced graphene oxide (rGO) whose properties are similar to those of pure graphene. We also present our experiments and the results in this field and the comparison of the efficiency of different methods of synthesis as well as the reduction of graphene oxide. To characterize the obtained...
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Review of the Application of Graphene-Based Coatings as Anticorrosion Layers
PublikacjaDue to the excellent properties of graphene, including flexibility that allows it to adjust to the curvature of the substrate surface, chemical inertness, and impermeability, graphene is used as an anticorrosion layer. In this review, we present the current state-of-the-art in the application of graphene in the field of protective coatings. This review provides detailed discussions about the protective properties of graphene coatings...
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Reduced Graphene Oxide Joins Graphene Oxide To Teach Undergraduate Students Core Chemistry and Nanotechnology Concepts
PublikacjaNovel carbon nanomaterials such as reduced graphene oxide (rGO) and graphene oxide (GO) can be easily incorporated into the undergraduate curriculum to discuss basic chemistry and nanotechnology concepts. This paper describes a laboratory experiment designed to study the differences between GO and rGO regarding their physico-chemical properties (e.g. color, hydrophobicity, type of functional groups, electrical conductivity etc.)....
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RECENT ADVANCES IN GRAPHENE APPLICATION FOR ELECTRONIC SENSING
PublikacjaThe great interest in graphene is caused by its potential for constructing various sensors exhibiting excellent parameters. The high carrier mobility and the unique band structure of graphene makes it promising especially in the field-effect transistors (GFET) applications. In this article, recent advances of the selected graphene-based sensor applications were presented and the possible directions for further investigations were...
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GRAPHENE-BASED SUPERCAPACITORS APPLICATION FOR ENERGY STORAGE
PublikacjaRecent advances in graphene-based supercapacitor technology for energy storage application were summarized. The comparison of different types of electrode materials in such supercapacitors was performed. The supercapacitors with graphene-based electrodes exhibit outstanding performance: high charge-discharge rate, high power density, high energy density and long cycle-life, what makes them suitable for various applications, e.g....
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Ionic liquids as an example of lubricating oils used in a field of tribology
PublikacjaPodczas prezentacji ustnej pokazano przykłady cieczy jonowych, ich możliwości w wykorzystaniu jako zastąpienie tradycyjnie używanych dziś smarów. Ponadto dokonano porównania kilku właściwości "tribologicznych" między cieczami jonowymi a obecnie wykorzystywanymi smarami
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Applying of Doped Graphene Oxide Coatings for Corrosion Prevention
PublikacjaINTRODUCTION Graphene is a carbonaceous material characterized by extraordinary properties (high electron mobility, high surface area, high mechanical strength of 1100 GPa, very dense network hindering the passage of even the smallest helium atoms) [1]. Therefore, it found many applications, also as an anti-corrosive layer [2]. Electrophoretic Deposition (EPD) is one of the methods to deposit coatings. However, due to slight solubility...
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On Applications of Fractional Derivatives in Circuit Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are discussed from the point of view of applications in the circuit theory. The properties of FO derivatives required for the circuit-level modelling are formulated. Potential problems related to the generalization of transmission line equations with the use of FO derivatives are presented. It is demonstrated that some of formulations of the FO derivatives have limited...
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3D porous graphene-based structures- synthesis and applications
PublikacjaPorous carbon-based materials are of the great industrial and academic interest due to their high surface area, low density, good electrical conductivity, chemical inertness and low cost of fabrication. Up to now, the main approach to obtain porous carbon structures has involved the pyrolysis of carbonaceous natural or synthetic precursors. After the isolation of graphene, the interest in 3D porous graphene-based structures (called...
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Silica-templated three-dimensional graphene xerogels
PublikacjaMost porous carbons require the uniform pore size distribution therefore many approaches have been applied to template the carbon scaffolds and among them the use of silica particles is the easiest and the most effective. After discovering of graphene, the whole family of new carbon nanomaterials arose and one of the promising materials is graphene xerogel (GX) with a three-dimensional, highly porous structure. This monograph reviews...
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On Applications of Fractional Derivatives in Electromagnetic Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are analysed from the point of view of applications in the electromagnetic theory. The mathematical problems related to the FO generalization of Maxwell's equations are investigated. The most popular formulations of the fractional derivatives, i.e., Riemann-Liouville, Caputo, Grünwald-Letnikov and Marchaud definitions, are considered. Properties of these derivatives are...
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The protective properties of graphene oxide coatings functionalized with phosphorus atoms.
PublikacjaRecently, electrophoretically deposited graphene oxide coatings are commonly applied as an anti-corrosion layer. However, improper adjustment of electrophoretic deposition (EPD) parameters as well as the hydrophilic nature of graphene oxide contribute to the formation of defects in the coatings and the increase in the wetting properties, respectively, and thus lead to a reduction of protective properties. The growth of wetting...
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Enhanced supercapacitor materials from pyrolyzed algae and graphene composites
PublikacjaThis study focuses on the synthesis and characterization of supercapacitor materials derived from pyrolyzed natural compounds. Four compounds were investigated: methylcellulose with lysine (ML), methylcellulose with lysine-graphene composite (MLG), algae (A), and algae-graphene composite (AG). The pyrolysis process was utilized to convert these natural compounds into carbon-based materials suitable for supercapacitor applications....
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Recent and Emerging Applications of Graphene-based metamaterials in Electromagnetics
PublikacjaSurface Plasmon Polaritons (SPPs) operating in mid-infrared up to terahertz (THz) frequencies have been traditionally manufactured on expensive metals such as gold, silver, etc. However, such metals have poor surface confinement that limits the optical applications of SPPs. The invention of graphene is a breakthrough in plasmon-based devices in terms of design, fabrication and applications, thanks to its plasmonic wave distribution,...
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New approach for the synthesis of Ag3PO4-graphene photocatalysts
PublikacjaA facile and effective plasma sputtering method for the preparation of a visible light active photocatalyst - rhombic dodecahedral silver phosphate Ag3PO4 covered with nanographene (Ag3PO4-GR) with improved stability has been developed. Proposed method allows for the usage of readily available materials for nanographene sputtering and for easy scaling-up. The stability improvement, confirmed by visible light-induced phenol degradation...
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Polyurethane Nanocomposites Containing Reduced Graphene Oxide, FTIR, Raman, and XRD Studies
PublikacjaRecently, graphene and other graphene-based materials have become an essential part of composite science and technology. Their unique properties are not only restricted to graphene but also shared with derivative compounds like graphene oxide, reduced graphene oxide, functionalized graphene, and so forth. One of the most structurally important materials, graphene oxide (GO), is prepared by the oxidation of graphite. Though removal...
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Graphene field-effect transistor application for flow sensing
PublikacjaMicroflow sensors offer great potential for applications in microfluidics and lab-on-a-chip systems. However, thermal-based sensors, which are commonly used in modern flow sensing technology, are mainly made of materials with positive temperature coefficients (PTC) and suffer from a self-heating effect and slow response time. Therefore, the design of novel devices and careful selection of materials are required to improve the overall...
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Elastic polyurethane foams containing graphene nanoplatelets
PublikacjaElastic polyurethane foams were produced from two-component polyurethane systems (SPECFLEX NE 113 izocyjanian/NR 816 poliol system—SPC and Elastic MBMarket company system POLYOL ET MB 500/ISO ET MB 800—ET) by using a one-step method. The foams were a graphene nanoplatelets (GNP) in the amount ranging from 1 to 2 wt.%. The effect of the nanofiller on polyurethane matrix was determined by analyzing the chemical structure, static...
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Molecular Dynamics simulations of thermal conductivity of penta-graphene
PublikacjaThe thermal conductivity of penta-graphene (PG), a new two dimensional carbon allotrope and its dependence on temperature, strain, and direction are studied in this paper. The thermal conductivity of PG is investigated using a non-equilibrium molecular dynamics simulation (NEMD) with the Two Region Method by applying the optimized Tersoff interatomic potential. Our study shows that the thermal conductivity of PG (determined for...
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Chemical modifications of graphene and their influence on properties of polyurethane composites: a review
PublikacjaPolyurethane composites are materials of great interest nowadays due to their wide range of available forms and applications in industry. Controlling and achieving unique properties via matrix modifications and addition of various specific nanofillers seems be one of the key elements to success. The purpose of this work is to briefly present some examples of graphene nanoderivatives, their syntheses, properties and influence on...
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Reviewing the recent developments of using graphene-based nanosized materials in membrane separations
PublikacjaAccording to the potentialities of graphene-based materials and their unique physicochemical properties. Such 2D nanomaterials are likely to be the most implemented within the improvement of the selective separations of polymer membranes, together with enhanced physicochemical properties (such as hydrophilicity/hydrophobicity, transport of molecules, mechanical and thermal features, among others). Hence, this review compiles and...
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Tailoring Graphene to Achieve Negative Poisson's Ratio Properties
PublikacjaGraphene can be made auxetic through the introduction of vacancy defects. This results in the thinnest negative Poisson's ratio material at ambient conditions known so far, an effect achieved via a nanoscale de-wrinkling mechanism that mimics the behavior at the macroscale exhibited by a crumpled sheet of paper when stretched.
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Interrelated shape memory and Payne effect in polyurethane/graphene oxide nanocomposites
PublikacjaWe report the fabrication of graphene oxide (GO) based polyurethane (PU) nanocomposites by a simple method of mixing and their shape memory properties at different temperatures. Both the polymer and the filler were synthesized in the laboratory by simple and easy methods – PU by pre-polymer method and GO by improved graphene oxide synthesis method. High molecular level dispersion of GO platelets within the PU matrix and thus good...
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Probability distribution of flicker noise in AuNPdecorated graphene–Si Schottky barrier diode
PublikacjaWe present results of the probability distribution analysis of flicker noise generated in Au nanoparticle (AuNP) decorated graphene–Si Schottky barrier diodes with and without yellow light illumination (592 nm), close to the localized surface plasmon resonance in the AuNPs (586 nm). The AuNPs occupy imperfections in the single-layer graphene and reduce the flicker noise intensity generated in the graphene layer. The estimated probability...
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Evaluating the antibacterial activity of muramyl dipeptide derivatives, retro-tuftsin derivatives, and anthraquinone oligopeptides against a range of pathogenic bacteria
PublikacjaSearch for new and efficient antibiotic is crucial because of microbial drug resistance and problems with side effects of the administered medication. In this study, we evaluate the in vitro microbiological activity of muramyl dipeptide derivatives, retro-tuftsin derivatives (i.e., tuftsin with reversed amino acid sequences), and combinations of retro-tuftsin derivatives with substituted anthraquinones. The potency of the investigated...
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Catalytic Asymmetric Synthesis of Isochroman Derivatives
PublikacjaThe isochroman scaffold constitutes an important structural unit, which is present in various bioactive natural products and synthetic pharmaceutical compounds exhibiting wide arrays of biological properties. Hence the synthesis of this class of heterocyclic compounds in a stereoselective fashion is highly significant and desirable. In the last decade, a substantial advancement has been witnessed ln the catalytic asymmetric...
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Characterization of PVDF/Graphene Nanocomposite Membranes for Water Desalination with Enhanced Antifungal Activity
PublikacjaSeawater desalination is a worldwide concern for the sustainable production of drinking water. In this regard, membrane distillation (MD) has shown the potential for effective brine treatment. However, the lack of appropriate MD membranes limits its industrial expansion since they experience fouling and wetting issues. Therefore, hydrophobic membranes are promising candidates to successfully deal with such phenomena that are typical...
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Comprehensive study on graphene hydrogels and aerogels synthesis and their ability of gold nanoparticles adsorption
PublikacjaGraphene hydrogels were prepared by ascorbic acid-assisted gelation of graphene oxide (GO) aqueous suspensions both in acidic and basic conditions. Different mass ratio of ascorbic acid (AA) to GO was used (namely 20:1 and 10:1). In order to eliminate the influence of AA on the final structure of hydrogels, samples without AA were prepared by a hydrothermal gelation of GO in an autoclave. An in-depth structural characterization...
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Pulsed UV-irradiated Graphene Sensors for Ethanol Detection at Room Temperature
PublikacjaA graphene-based gas sensor fabricated in a FET (GFET) configuration and its sensitivity towards ethanol and methane is reported. Detection of ethanol at the level of 100 ppm was observed under pulsed UV irradiation and after cleaning by UV light in the N2 ambient. Reduction of the frequency of UV irradiation pulses resulted in increased changes in sensor resistance in the presence of ethanol. Improved sensing behavior was ascribed...
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The behavioural model of graphene field-effect transistor
PublikacjaThe behavioural model of a graphene field-effect transistor (GFET) is proposed. In this approach the GFET element is treated as a “black box” with only external terminals available and without considering the physical phenomena directly. The presented circuit model was constructed to reflect steady-states characteristics taking also into account GFET capacitances. The authors’ model is defined by a relatively small number of equations...
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Fabrication of anti-corrosion nitrogen doped graphene oxide coatings by electrophoretic deposition
PublikacjaThis work assesses anti-corrosion properties of graphene and N-doped graphene coatings deposited on copper by an electrophoretic method. Graphene oxide (GO) precursor was synthesized by an improved Hummers' method, whereas N-doping was performed hydrothermally in the presence of ammonia. After nitrogenation, doped graphene oxide samples (NGO) contained a reduced amount of oxygen and about 9% w/w nitrogen as pyridinic, pyrrole,...
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The impact of graphene on the electrochemical performance of BiMeVOx catalysts in water splitting
PublikacjaThe development of efficient catalysts for electrochemical water splitting has become a significant contemporary challenge. Transition metal oxides, due to their unique electrochemical properties, have emerged as promising candidates. Among these, a group of BiMeVOx-based compounds shows particular potential for practical applications in hydrogen and oxygen evolution reactions. However, improvement is still necessary to achieve...
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Functionalization of graphene oxide coatings with phosphorus atoms and their corrosion resistance in sodium chloride environment
PublikacjaIn this work, we compared corrosion resistance of graphene oxide, and phosphorus functionalized reduced graphene oxide coatings obtained as a result of electrophoretic deposition on the copper substrate. Doping graphene oxide with phosphorus atoms was performed by a hydrothermal method in the presence of different amounts of phosphoric acid. Structural studies confirmed the insertion of phosphorus atoms into the graphene oxide...
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On Applications of Elements Modelled by Fractional Derivatives in Circuit Theory
PublikacjaIn this paper, concepts of fractional-order (FO) derivatives are reviewed and discussed with regard to element models applied in the circuit theory. The properties of FO derivatives required for the circuit-level modeling are formulated. Potential problems related to the generalization of transmission-line equations with the use of FO derivatives are presented. It is demonstrated that some formulations of FO derivatives have limited...