Mechanical exfoliation to make graphene and visualization. This paper reports high concentration production of fewlayer graphene in dmso dimethyl sulfoxide as solvent through liquid phase exfoliation assisted with sonication. So, exfoliation using odcb solvent has been chosen. Here, we demonstrate graphene dispersions with concentrations up to 0. Solventexfoliated graphene at extremely high concentration article in langmuir 2715. Surfactant mediated liquid phase exfoliation of graphene. Production of highconcentration graphene dispersions in. Spontaneous highconcentration dispersions and liquid. Production of highconcentration graphene dispersions in lowboilingpoint organic solvents by liquidphase noncovalent exfoliation of graphite with a hyperbranched polyethylene and formation of grapheneethylene copolymer composites. Liquidphase exfoliation of graphite into single and fewlayer. Graphene acts as a high efficiency and highly selective extraction platform for dna in a. Graphene via sonication assisted liquidphase exfoliation1. Substantial success has been achieved thus far in the lpe of graphene employing numerous solvent systems. Background history graphene is a flat sheet of carbon just one atom thick.
Stern suggested an even further refined model combining the helmholtz and gouy. Liquidphase exfoliation of fewlayer graphene and effect. Introduction 15 graphene is a oneatom thick twodimensional molecule exclusively made of sp2 hybridated carbon atoms. Graphene due to its high room temperature carrier mobility 15000 cm2v. However, for a long time there has been a huge gap between laboratory. In particular, the most effective exfoliation was obtained with 15 volume % of notbz in nmp as a solvent, with a concentration of exfoliated graphene of 250. Concentration solvent exfoliation of graphene, small on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at.
Fewlayer graphene obtained by electrochemical exfoliation. Graphene combines unique electronic properties and surprising quantum effects with outstanding thermal and mechanical properties1,2,3,4. The effect of surfactants and their concentrations on the. Graphene from graphite by electrochemical exfoliation. Graphene is an interesting material, but making enough of the stuff to do something useful can be a little tough.
Biodegradable and widely available from renewable sources, cnc have proven to be very efficient graphene stabilizers even at low concentrations 0. Enhancing liquid phase exfoliation of graphene in organic. This occurs because the energy required to exfoliate graphene is balanced by the solventgraphene interaction for solvents whose surface energy matches that of graphene. Fully exploiting the properties of graphene will require a method for the mass production of this remarkable material. This gives dispersions of graphene at concentrations of up to 1. For example, graphene can be produced by supercritical solvent exfoliation of graphite. Electrochemical exfoliation produces highquality graphene in a short time. High yield and high concentration fewlayer graphene.
Graphene has been produced by liquid phase exfoliation, which is the most probable method for commercial production of graphene for various industrial applications. Effect of sonication time on the yield and quality of graphene exfoliated in dmf has been studied. Microwaveassisted highyield exfoliation of vanadium. Propagative exfoliation of high quality graphene lan feng, yuewen liu, xingyan tang, yanmei piao, shufen chen, shunliu deng, suyuan xie, yuhuang wang, and lansun zheng department of chemistry and state key laboratory of physical chemistry of solid surface, college of chemistry and chemical engineering, xiamen university, xiamen 361005, china. The merits of our approach lie in the quick and complete removal of the remaining solvent from the exfoliated graphitic sheets without the help of high temperature annealing or long vacuum drying. Surfactantfree exfoliation of graphite in aqueous solutions karen b. The drying process of graphenepolymer composites fabricated by solutionprocessingfor excellent dispersion is time consuming and suffers from a. These require the development of production processes that are inexpensive and upscalable. From the early days of research on graphene, direct liquid phase exfoliation lpe of graphite has been considered as the most promising strategy to produce highquality mono or fewlayer graphene sheets in solvent dispersion forms. Graphene can be produced in aqueous surfactant solutions 12.
Concentration solvent exfoliation of graphene, small. The outstanding processability and electrical properties of these. Liquidphase exfoliated graphene for supercapacitors opus 4. The effect of surfactants and their concentrations on the liquidexfoliation of graphene shuai wang1, min yi1, shuaishuai liang1, zhigang shen1,2, xiaojing zhang1 and shulin ma1 1 beijing key laboratory for powder technology research and development, beijing university of aeronautics and astronautics, beijing 100191, china. By combining experimental and modeling investigations, the. The journal of physical chemistry c 20, 117 20, 1073010742.
Methods of forming graphene by graphite exfoliation. Since graphene has a highly conjugated system, it is easy to conduct strong interaction with conjugated structure. Combining the functionalization of graphene, zheng et al. Under these conditions, graphite is exfoliated as highquality graphene. Due to the high ionic strength of the solution, exfoliated graphene flakes tend to form. Pdf highconcentration solvent exfoliation of graphene.
For example, coleman and coworkers demonstrated the exfoliation of graphene at relatively high concentration in low boiling point solvents such as chloroform and isopropanol 20arlene et al. A supramolecular strategy to leverage the liquidphase. In the exfoliation process, hbpe adsorbs onto the surface of exfoliated graphene flakes. Solvothermalassisted liquidphase exfoliation of graphite.
We describe three related methods to disperse graphene in solvents with concentrations. Dispersion of graphene in ethanol using a simple solvent exchange methodw. Production of graphene by exfoliation of graphite in a. A rapidly increasing list of graphene production techniques have been developed to enable graphenes use in commercial applications isolated 2d crystals cannot be grown via chemical synthesis beyond small sizes even in principle, because the rapid growth of phonon density with increasing lateral size forces 2d crystallites to bend into the third dimension. Chapter 4 fabricating graphene by chemical exfoliation of. Exfoliation of threedimensional graphite into twodimensional graphene andor graphenelike sheets has attracted a lot of attention, because graphene has many potential applica. Request pdf highconcentration solvent exfoliation of graphene a method is demonstrated to prepare graphene dispersions at high. In the present work, the use of a commercial ionic liquid as a convenient solvent medium for graphite exfoliation in mild and easy conditions without any chemical modification is presented. Since 2008, when liquidphase exfoliation lpe of graphene via sonication was initiated. In this paper, by dispersing graphene powder at low boiling point solvent water or. Dryfe a, a school of chemistry, university of manchester, oxford road, manchester m 9pl, uk b department of physics, university of warwick, gibbet hill road, coventry cv4 7al, uk. The graphene formed using the exfoliation methods described herein can be used as an efficient and in some embodiments, an ultrahigh efficient extraction and detection platform for dna. Exploring the graphene material is premised on the graphene sheets being singlelayer graphene sg or bilayer graphene bg state, and graphene suspension keeps stably disperse are critical. High quality graphene by taylorcouette flow high shear.
Request pdf highconcentration solvent exfoliation of graphene a method is demonstrated to prepare graphene dispersions at high concentrations, up to 1. Commercialization of graphene based applications inevitably requires cost effective mass production. The solvent nmp has been reported to yield high quality graphene sheets because of the strong interaction between nmp and carbon nanotube sidewall that makes the energetic penalty of exfoliation and solvation become small. To ensure most of the microwave energy was concentrated on the v 2 o 5 particles and the adsorbed water molecules during the microwaveassisted exfoliation i. Exfoliation of highquality graphene in volatile and. Production of high concentration graphene dispersions in lowboilingpoint organic solvents by liquidphase noncovalent exfoliation of graphite with a hyperbranched polyethylene and formation of graphene ethylene copolymer composites. Obtained for the first time in 2004,1 graphene can be formally. Fg was found to be dispersible in watersurfactant pluronic f127 to give highly concentrated dispersions reaching 4 g l. Concentration solvent exfoliation of graphene khan. The highquality graphene sheets obtained in this work make them suitable for application in many fields such as energystorage materials and polymer composites. Single stage electrochemical exfoliation method for the. Extensive research suggests a bright future for the graphene market. Importantly, a high percentage of singlelayer graphene flakes is revealed by highresolution transmission electron microscopy and raman spectroscopy analyses. Spontaneous exfoliation of hopg in chlorosulfonic acid was achieved by behabtu et al.
Advanced institutes of convergence technology, seoul national university, suwon. Many potential applications, including electronics and. Highyield exfoliation of threedimensional graphite into. The ability to disperse pristine graphene at high concentrations in aqueous solutions is an enabling step for largescale processing and emerging biomedical applications. Enhancing the liquidphase exfoliation of graphene in. These criteria are met in liquidphase exfoliation lpe, a technique that can be enhanced when specific. Generation graphene from electrochemical approaches.
Direct exfoliation produces highquality graphene layers with good crystalline structure, low defect density, and high electrical conductivity. Highconcentration solvent exfoliation of graphene request pdf. The procedure of the microwaveassisted exfoliation method to prepare v 2 o 5 nanoribbons from crystalline bulk. Graphite can be highly exfoliated in the solvent n. Liquidphase exfoliation of graphite to produce high. In this paper, we report on the successful preparation of highquality graphene sheets with a largesize in n,ndimethylformamide dmf solvent by sonicationfree liquidphase exfoliation lpe of graphite assisted with urea as the precursor of the intercalating agent. University of groningen dispersion of graphene in ethanol. Electronic supplementary information high shearinduced exfoliation of graphite into high quality graphene by taylorcouette flow tuan sang tran, seung jun park, sung sic yoo, taerin lee, taeyoung kim department of bionanotechnology, gachon university, seongnam, gyeonggido 120, korea. Graphene has unique physical and chemical properties, making it appealing for a number of applications in optoelectronics, sensing, photonics, composites, and smart coatings, just to cite a few. To confirm the presence of few layer graphene, its dispersion, which exhibits tyndall effect, was characterized by raman and uv spectroscopies, and atomic force and field emission electron microscopies. Surfactantfree exfoliation of graphite in aqueous solutions. This process relies on lowpower sonication for long times, up to 460 h. The prepared graphene sheets have a high quality, and the concentration of graphene in the dispersion is as high as 0. Preparation of ultrahigh concentration graphene in water.
A nondispersion strategy for largescale production of ultrahigh. Liquid exfoliation of defectfree graphene accounts of. Solventexfoliated graphene at extremely high concentration. High concentration fewlayer graphene sheets obtained by. Efficient graphene exfoliation in a nontraditional solvent, ethanol, is achieved through the addition of a stabilizing polymer, ethyl cellulose.
Highconcentration aqueous dispersions of graphene using. The exfoliation of graphite to give graphene is one of the most promising ways to. Highquality fewlayer to multilayer graphene sheets were exfoliated in n,ndimethylformamide dmf and 1propanol by simple liquidphase exfoliation method. The solutions were spincoated on psi and glass substrates for. A method is demonstrated to prepare graphene dispersions at high concentrations, up to 1. Stable highconcentration aqueous dispersions 1 mg ml. Preparation of highquality graphene with a largesize by. Preparation of high concentration graphene dispersion with. About europe pmc funders joining europe pmc governance roadmap outreach tools. Highly concentrated graphene solutions via polymer.
A simple method for graphene production based on exfoliation of graphite in water using 1pyrenesulfonic acid sodium salt h. Description of additional supplementary files167k, pdf. Highyield production of graphene by liquidphase exfoliation of graphite. Highconcentration aqueous dispersions of graphene using nonionic, biocompatible block copolymers. Single stage electrochemical exfoliation method for the production of fewlayer graphene via intercalation of tetraalkylammonium cations 5 adam j. Since 2008, when liquidphase exfoliation lpe of graphene via. Aqueous dispersions of graphene from electrochemically. Strong bonds link each carbon atom to three other carbon atoms and form hexagonal sixsided shapes.
Iterative solvent exchange is further demonstrated as a rapid, roomtemperature, ultracentrifugationfree approach to concentrate the graphene solution to a level exceeding 1 mgml. Fewlayer graphene obtained by electrochemical exfoliation of graphite cathode ming zhoua, jie tangb, qian chengb, gaojie xua, ping cuia, luchang qina,c. The efficiency of the exfoliation in terms of concentration of exfoliated graphene is found to be proportional to the length of the employed fatty acid. A high graphene dispersion concentration can be obtained by selecting a suitable solvent that includes organic solvents, 6,11121415 16 17181920 organosilanes, 21 ionic. This process relies on lowpower sonication for long. Liquidphase exfoliation of graphene semantic scholar. We report in this paper the successful production of stable high concentration graphene dispersions in lowboilingpoint, lowpolarity conventional organic solvents chloroform and thf by liquidphase noncovalent exfoliation of graphite assisted with a hyperbranched polyethylene hbpe as the stabilizer.
In this paper, an effort has been made to demonstrate the preparation of homogeneous and stable dispersion of graphene in odcb solvent. This process can be easily scaled up for better performance, and resulting high concentration graphene can be used for the fabrication of the. For example, the sonication of graphite in an organic solvent normally produces a graphene yield of less than 1%. In this procedure, solvents reach or exceed their critical point, presenting outstanding wetting properties, low interfacial tension, low viscosity, and high diffusion coefficients. Structural and electrical properties of graphene oxidedoped pvapvp blend nanocomposite polymer films. Thats why were always on the lookout for new methods, like this elect. Liquidphase exfoliation of graphite into single and few.
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