Articles de revues : « Graphene - Physical Properties »

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Wakabayashi, Katsunori. « Physical properties of nano-graphene ». TANSO 2010, n^o 243 (2010) : 116–20. http://dx.doi.org/10.7209/tanso.2010.116.

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Wakabayashi, Katsunori. « Physical properties of nano-graphene ». Carbon 48, n^o 14 (novembre 2010) : 4216. http://dx.doi.org/10.1016/j.carbon.2010.06.071.

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Murav’ev, V. V., et V. M. Mishchenka. « Ab-initio simulation of hydrogenated graphene properties ». Doklady BGUIR 19, n^o 8 (1 janvier 2022) : 5–9. http://dx.doi.org/10.35596/1729-7648-2021-19-8-5-9.

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Ab-initio simulation of hydrogenated graphene properties was performed. At present, graphene is considered one of the most promising materials for the formation of new semiconductor devices with good characteristics. Graphene has been the subject of many recent investigations due to its peculiar transport, mechanical and others properties [1]. The chemical modification of graphene named as graphane has recently entered the investigation as a possible candidate to solve problems connected with the lack of a graphene bandgap. Graphane is a compound material consisting of two-dimensional graphene bonded by some atoms of hydrogen. The investigation shows that graphane has the three valley Г-М-K band structure with the Г valley, which has the smallest energy gap between the conductivity zone and the valence zone. The calculation of relative electron masses and non-parabolic coefficients in Г, М and K valleys was performed. Based on the obtained characteristics, it is possible to implement a statistical multi-particle Monte Carlo method to determine the characteristics of electron transfer in heterostructure semiconductor devices. A research on modified graphene structures is important for fundamental science and technological applications in high-speed transistor structures operating in the microwave and very high frequency ranges.

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Wei, Weili, et Xiaogang Qu. « Extraordinary Physical Properties of Functionalized Graphene ». Small 8, n^o 14 (4 juin 2012) : 2138–51. http://dx.doi.org/10.1002/smll.201200104.

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Langston, Xavier, et Keith E. Whitener. « Graphene Transfer : A Physical Perspective ». Nanomaterials 11, n^o 11 (25 octobre 2021) : 2837. http://dx.doi.org/10.3390/nano11112837.

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Graphene, synthesized either epitaxially on silicon carbide or via chemical vapor deposition (CVD) on a transition metal, is gathering an increasing amount of interest from industrial and commercial ventures due to its remarkable electronic, mechanical, and thermal properties, as well as the ease with which it can be incorporated into devices. To exploit these superlative properties, it is generally necessary to transfer graphene from its conductive growth substrate to a more appropriate target substrate. In this review, we analyze the literature describing graphene transfer methods developed over the last decade. We present a simple physical model of the adhesion of graphene to its substrate, and we use this model to organize the various graphene transfer techniques by how they tackle the problem of modulating the adhesion energy between graphene and its substrate. We consider the challenges inherent in both delamination of graphene from its original substrate as well as relamination of graphene onto its target substrate, and we show how our simple model can rationalize various transfer strategies to mitigate these challenges and overcome the introduction of impurities and defects into the graphene. Our analysis of graphene transfer strategies concludes with a suggestion of possible future directions for the field.

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De Sanctis, Adolfo, Jake Mehew, Monica Craciun et Saverio Russo. « Graphene-Based Light Sensing : Fabrication, Characterisation, Physical Properties and Performance ». Materials 11, n^o 9 (18 septembre 2018) : 1762. http://dx.doi.org/10.3390/ma11091762.

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Graphene and graphene-based materials exhibit exceptional optical and electrical properties with great promise for novel applications in light detection. However, several challenges prevent the full exploitation of these properties in commercial devices. Such challenges include the limited linear dynamic range (LDR) of graphene-based photodetectors, the lack of efficient generation and extraction of photoexcited charges, the smearing of photoactive junctions due to hot-carriers effects, large-scale fabrication and ultimately the environmental stability of the constituent materials. In order to overcome the aforementioned limits, different approaches to tune the properties of graphene have been explored. A new class of graphene-based devices has emerged where chemical functionalisation, hybridisation with light-sensitising materials and the formation of heterostructures with other 2D materials have led to improved performance, stability or versatility. For example, intercalation of graphene with FeCl 3 is highly stable in ambient conditions and can be used to define photo-active junctions characterized by an unprecedented LDR while graphene oxide (GO) is a very scalable and versatile material which supports the photodetection from UV to THz frequencies. Nanoparticles and quantum dots have been used to enhance the absorption of pristine graphene and to enable high gain thanks to the photogating effect. In the same way, hybrid detectors made from stacked sequences of graphene and layered transition-metal dichalcogenides enabled a class of devices with high gain and responsivity. In this work, we will review the performance and advances in functionalised graphene and hybrid photodetectors, with particular focus on the physical mechanisms governing the photoresponse, the performance and possible future paths of investigation.

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Wei, Bing Wei, Dong Qu, Chun Feng Hu, Fang Zhi Li, Tian Liang Zhou, Rong Jun Xie et Zhi Ming Zhou. « Synthesis and Physical Properties of Graphene Nanosheets Reinforced Copper Composites ». Advanced Materials Research 833 (novembre 2013) : 310–14. http://dx.doi.org/10.4028/www.scientific.net/amr.833.310.

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Cu/graphene nanosheets composites were fabricated at 800°C by the hot-pressing method using Cu and graphene as initial materials. Graphene content was 1 wt. %-5 wt. %. The fracture morphology and physical properties of the composites were investigated. It was found that the relative density increased with the increment of graphene content from 1 wt% to 5 wt. % with reaching its highest level (96.68%) at 5wt. %. The composites have the anisotropic property which is vertical to the direction of pressure is higher than parallel to the direction of pressure. With the increasing of graphene content, the thermal conductivity property and the electronic conductivity decrease first and then increase with the minimum thermal conductivity and electric conductivity at 3wt%~4wt%.

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Fuhrer, Michael S., Chun Ning Lau et Allan H. MacDonald. « Graphene : Materially Better Carbon ». MRS Bulletin 35, n^o 4 (avril 2010) : 289–95. http://dx.doi.org/10.1557/mrs2010.551.

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AbstractGraphene, a single atom–thick plane of carbon atoms arranged in a honeycomb lattice, has captivated the attention of physicists, materials scientists, and engineers alike over the five years following its experimental isolation. Graphene is a fundamentally new type of electronic material whose electrons are strictly confined to a two-dimensional plane and exhibit properties akin to those of ultrarelativistic particles. Graphene's two-dimensional form suggests compatibility with conventional wafer processing technology. Extraordinary physical properties, including exceedingly high charge carrier mobility, current-carrying capacity, mechanical strength, and thermal conductivity, make it an enticing candidate for new electronic technologies both within and beyond complementary metal oxide semiconductors (CMOS). Immediate graphene applications include high-speed analog electronics and highly conductive, flexible, transparent thin films for displays and optoelectronics. Currently, much graphene research is focused on generating and tuning a bandgap and on novel device structures that exploit graphene's extraordinary electrical, optical, and mechanical properties.

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Hua, Lei. « Enhanced Physical Properties of PEO /GRAPHENE Composites ». Journal of Physics : Conference Series 1798, n^o 1 (1 février 2021) : 012010. http://dx.doi.org/10.1088/1742-6596/1798/1/012010.

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NORIMATSU, Wataru. « Structural and Physical Properties of Epitaxial Graphene ». Nihon Kessho Gakkaishi 61, n^o 1 (28 février 2019) : 35–42. http://dx.doi.org/10.5940/jcrsj.61.35.

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Thema, F. T., P. Beukes, Z. Y. Nuru, L. Kotsedi, M. Khenfouch, M. S. Dhlamini, B. Julies, E. Iwuohah et M. Maaza. « Physical Properties of Graphene via γ-radiolysis of Exfoliated Graphene Oxide ». Materials Today : Proceedings 2, n^o 7 (2015) : 4038–45. http://dx.doi.org/10.1016/j.matpr.2015.08.033.

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Ferreira, Willian Hermogenes, et Cristina Tristão Andrade. « Physical and Biodegradation Properties of Graphene Derivatives/Thermoplastic Starch Composites ». Polysaccharides 2, n^o 3 (6 juillet 2021) : 582–93. http://dx.doi.org/10.3390/polysaccharides2030035.

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Development of biodegradable materials for packaging is an issue of the utmost importance. These materials are an alternative to petroleum-based polymers, which contribute to environment pollution after disposal. In this work, graphene oxide (GO) and glucose-reduced graphene oxide (rGO-g) were incorporated to thermoplastic starch (TPS) by melt extrusion. The TPS/GO and TPS/rGO-g composites had their physical properties and biodegradability compared. X-ray diffraction (XRD) showed that the type of graphene used led to different dispersion levels of graphene sheets, and to changes in the crystalline structure of TPS. Tensile tests carried out for the compression-molded composites indicated that TPS/rGO-g composites presented better mechanical performance. The Young’s modulus (E) increased from E = (28.6 ± 2.7) MPa, for TPS, to E = (110.6 ± 9.5) MPa and to (144.2 ± 11.2) MPa for TPS with rGO-g incorporated at 1.0 and 2.0 mass% content, respectively. The acid groups from graphene derivatives promoted glycosidic bond breakage of starch molecules and improved biodegradation of the composites. GO is well-dispersed in the TPS matrix, which contributes to biodegradation. For TPS/rGO-g materials, biodegradation was influenced by rGO-g dispersion level.

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Zhang, Liying, Chao Wu, Xiangdong Ding, Yong Fang et Jun Sun. « Separation selectivity and structural flexibility of graphene-like 2-dimensional membranes ». Physical Chemistry Chemical Physics 20, n^o 27 (2018) : 18192–99. http://dx.doi.org/10.1039/c8cp00466h.

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Single-layer membranes of porous graphene, graphyne derivatives (α/α2/β-graphyne), and porous boron nitride (BN) with similar pore sizes (approximately 8 × 6 Å) have shown different separation properties toward alkane isomers.

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Bastiurea, Marian, Magdalena Silvia Rodeanu, Dumitru Dima, Monica Murarescu et Gabriel Andrei. « Evaluation of Mechanical Properties of Polyester Composite with Graphene and Graphite through Three-Point Bending Test ». Applied Mechanics and Materials 659 (octobre 2014) : 22–27. http://dx.doi.org/10.4028/www.scientific.net/amm.659.22.

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Graphenes have aroused great interest among the scientists lately, due to their special physical properties which are supposed to be transferred to composite materials [1,2,3,6]. Some polymers show low mechanical properties which can be improved by adding various types of materials [9,13]. Using nanoparticles, an enhancement of mechanical, thermal and electrical properties can be obtained, even for small contents of additives [10,11,12,14,15,16]. The evaluation of mechanical properties of polymer composites with graphene can be achieved relying on the three-point bending tests [4]. This work presents a few conclusions resulting from the three points bending tests of the polyester composites with graphene and graphite [7,8].

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Wu, Fan, Wenyuan Xu, Fengfa Zhang et He Wu. « Grey Correlation Analysis of Physical Properties and Evaluation Index of Graphene-Oxide-Modified Asphalt ». Coatings 12, n^o 6 (3 juin 2022) : 770. http://dx.doi.org/10.3390/coatings12060770.

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The purpose of this study is to analyze the behavior of the performance index of graphene-oxide-modified asphalt. The deviation problem caused by determining graphene oxide content by single performance or several independent properties is also investigated. By testing the physical properties of graphene-oxide-modified asphalt with different admixtures (0%, 0.5%, 1.0%, 1.5%, 2.0% by mass) in terms of viscosity, penetration, softening point, ductility, rheology, etc., it is concluded that the addition of graphene oxide could improve the individual properties of the matrix asphalt by 3% to 250%. Moreover, the grey correlation analysis method is used to calculate and analyze the correlation between the performance of graphene-oxide-modified asphalt and the content of graphene oxide. The latter has the most significant effect on the softening point, the penetration, and the 135 °C Brookfield viscosity of modified asphalt. The content of graphene oxide in graphene-oxide-modified asphalt is calculated based on the above three performance indexes, and an estimation error of less than 0.15% is observed. This proves that the new determination method is reasonable. Finally, by combining the macroscopic properties and the multi-factor statistical analysis, a reference basis is provided for the quality control of the graphene-oxide-modified asphalt.

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Baimova, Julia A. « Property control by elastic strain engineering : Application to graphene ». Journal of Micromechanics and Molecular Physics 02, n^o 01 (mars 2017) : 1750001. http://dx.doi.org/10.1142/s2424913017500011.

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Various carbon nanostructures, including graphene, are of great interest nowadays for many applications. It has been shown that graphene has unique physical and mechanical properties and its properties can be controlled by the applied strain. The objective of the present paper is to describe several physical properties of graphene that can be controlled by means of elastic strain engineering. The space of in-plane elastic strain components is divided into regions with different structural configurations and physical properties of graphene. It is shown that a gap in the phonon density of states is observed when graphene is strained close to the appearance of ripples. Sound velocities of unstrained graphene do not depend on the propagation direction but application of strain, apart hydrostatic tension, makes graphene elastically anisotropic. The orientation, amplitude and wavelength of unidirectional ripples in graphene can be controlled by a change in the components of the applied strain.

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Shul’zhenko, Alexandr A., Lucyna Jaworska, Alexandr N. Sokolov, Vladislav G. Gargin et Ludmila A. Romanko. « ELECTRICALLY CONDUCTIVE POLYCRYSTALLINE SUPER HARD MATERIAL BASED ON DIAMOND AND n-LAYER GRAPHENES ». IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 59, n^o 8 (17 juillet 2018) : 69. http://dx.doi.org/10.6060/tcct.20165908.25y.

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The electrical and physical properties of the electrically conductive super hard material on the basis of polycrystalline diamond and n-layered graphenes obtained at high pressures and temperatures were studied. It was established that the increase in graphene in a polycrystalline diamond compact leads to a sharp decrease in resistance. Wherein the hardness of the samples is slightly inferior to the hardness of diamond poly crystals obtained without the use of graphene.

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Wu, Yu-You, Longxin Que, Zhaoyang Cui et Paul Lambert. « Physical Properties of Concrete Containing Graphene Oxide Nanosheets ». Materials 12, n^o 10 (26 mai 2019) : 1707. http://dx.doi.org/10.3390/ma12101707.

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Concrete made from ordinary Portland cement is one of the most widely used construction materials due to its excellent compressive strength. However, concrete lacks ductility resulting in low tensile strength and flexural strength, and poor resistance to crack formation. Studies have demonstrated that the addition of graphene oxide (GO) nanosheet can effectively enhance the compressive and flexural properties of ordinary Portland cement paste, confirming GO nanosheet as an excellent candidate for using as nano-reinforcement in cement-based composites. To date, the majority of studies have focused on cement pastes and mortars. Only limited investigations into concretes incorporating GO nanosheets have been reported. This paper presents an experimental investigation on the slump and physical properties of concrete reinforced with GO nanosheets at additions from 0.00% to 0.08% by weight of cement and a water–cement ratio of 0.5. The study demonstrates that the addition of GO nanosheets improves the compressive strength, flexural strength, and split tensile strength of concrete, whereas the slump of concrete decreases with increasing GO nanosheet content. The results also demonstrate that 0.03% by weight of cement is the optimum value of GO nanosheet dosage for improving the split tensile strength of concrete.

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Triantou, Marianna, Nadia Todorova, Tatiana Giannakopoulou, Tiverios Vaimakis et Christos Trapalis. « Physical Properties of Photo-Aged Graphene/Polypropylene Nanocomposites ». Journal of Nanoscience and Nanotechnology 18, n^o 7 (1 juillet 2018) : 5033–41. http://dx.doi.org/10.1166/jnn.2018.15335.

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Sagar, Rizwan Ur Rehman, Chen Lifang, Ayaz Ali, Muhammad Farooq Khan, Mudassar Abbas, Muhamad Imran Malik, Karim Khan, Jinming Zeng, Tauseef Anwar et Tongxiang Liang. « Unusual magnetotransport properties in graphene fibers ». Physical Chemistry Chemical Physics 22, n^o 44 (2020) : 25712–19. http://dx.doi.org/10.1039/d0cp05209d.

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Kumar, Sanjay, Himanshi, Jyoti Prakash, Ankit Verma, Suman, Rohit Jasrotia, Abhishek Kandwal et al. « A Review on Properties and Environmental Applications of Graphene and Its Derivative-Based Composites ». Catalysts 13, n^o 1 (4 janvier 2023) : 111. http://dx.doi.org/10.3390/catal13010111.

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Graphene-based materials have gained a lot of scientific interest in the research era of modern technology, which can be quite flexible. Graphene has become popular as a potential material for the manufacture of a wide range of technologies due to its remarkable electrical, mechanical, and optical traits. Due to these excellent characteristics, the derivatives of graphene can be functionalized in various applications including environmental, medical, electronic, defence applications, and many more. In this review paper, we discussed the different synthesis methods for the extraction of graphene and its derivatives. The different traits of graphene and its derivatives such as structural, mechanical, and optical were also discussed. An extensive literature review on the application of graphene-based composites is presented in this work. We also outlined graphene’s potential in the realm of environmental purification through different techniques such as filtration, adsorption, and photocatalysis. Lastly, the challenges and opportunities of graphene and its derivatives for advanced environmental applications were reported.

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Kausar, Ayesha, Ishaq Ahmad, O. Aldaghri, Khalid H. Ibnaouf et M. H. Eisa. « Shape Memory Graphene Nanocomposites—Fundamentals, Properties, and Significance ». Processes 11, n^o 4 (11 avril 2023) : 1171. http://dx.doi.org/10.3390/pr11041171.

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Shape memory nanocomposites are excellent smart materials which can switch between a variable temporary shape and their original shape upon exposure to external stimuli such as heat, light, electricity, magnetic fields, moisture, chemicals, pH, etc. Numerous nanofillers have been introduced in shape memory polymers such as carbon nanotubes, graphene, nanodiamonds, carbon nanofibers, etc. Among nanocarbons, graphene has attracted research interest for the development of shape memory polymer/graphene nanocomposites. Graphene is a unique one-atom-thick two-dimensional nanosheet of sp2-hybridized carbon atoms. Graphene has been used as an effective nanofiller in shape memory polymeric nanocomposites owing to its remarkable electrical conductivity, flexibility, strength, and heat stability. Thermoplastics as well as thermoset matrices have been used to form the shape memory nanomaterials with graphene nanofiller. In shape memory polymer/graphene nanocomposites, their shape has been fixed above the transition temperature and then transformed to the original shape through an external stimulus. The inclusion of graphene in nanocomposites can cause fast switching of their temporary shape to their original shape. Fine graphene dispersion, matrix–nanofiller interactions, and compatible interface development can lead to high-performance shape memory graphene-derived nanocomposites. Consequently, this review focuses on an important class of shape memory graphene-based nanocomposites. The fabrication, physical properties, and shape memory actuation of polymer/graphene nanocomposites are discussed. The stimuli-responsive polymer/graphene nanocomposites mostly revealed heat-, electricity-, and light-induced effects. The inclusion of graphene enhanced the physical/covalent linking, shape recovery, shape fixity, flexibility, and crystallization effects in the polymers. Furthermore, potential applications of these materials are observed in the aerospace/automobile industries, civil engineering, and biomaterials.

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Wang, Lan, Ning An, Xusheng He, Xinfeng Zhang, Ao Zhu, Baicheng Yao et Yaxin Zhang. « Dynamic and Active THz Graphene Metamaterial Devices ». Nanomaterials 12, n^o 12 (17 juin 2022) : 2097. http://dx.doi.org/10.3390/nano12122097.

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In recent years, terahertz waves have attracted significant attention for their promising applications. Due to a broadband optical response, an ultra-fast relaxation time, a high nonlinear coefficient of graphene, and the flexible and controllable physical characteristics of its meta-structure, graphene metamaterial has been widely explored in interdisciplinary frontier research, especially in the technologically important terahertz (THz) frequency range. Here, graphene’s linear and nonlinear properties and typical applications of graphene metamaterial are reviewed. Specifically, the discussion focuses on applications in optically and electrically actuated terahertz amplitude, phase, and harmonic generation. The review concludes with a brief examination of potential prospects and trends in graphene metamaterial.

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Seok, Jae-Wuk, et A.-Young Sung. « Physical Properties of High Functional Contact Lenses with Hydrophilic Substance and Graphene Oxide Nanocolloids ». Journal of Nanoscience and Nanotechnology 20, n^o 8 (1 août 2020) : 4860–65. http://dx.doi.org/10.1166/jnn.2020.17819.

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The purpose of this experiment is to evaluate the physical properties of contact lenses made by adding hydrophilic Hyaluronic acid (HA) and Methacrylic acid (MA) as additives and Graphene oxide nanocolloids. As a contact lens, AIBN (Azobisisobutyronitrile) was used as an initiator with HEMA (2-hydroxy methyl methacrylate) and EGDMA (ethylene glycol dimethacrylate) as a cross-linker. Hyaluronic acid (HA) and methacrylic acid (MA) were added at 5%, respectively. Graphene oxide nanocolloids were added at 0.1%, 0.3% and 0.5%, respectively. Each prepared contact lens was hydrated in 99% NaCl saline solution for 24 hours. And the basic physical properties of contact lenses were evaluated and compared. The refractive index of the sample with hyaluronic acid and MA added was 1.4390, which was not significantly different from that of the basic combination contact lens sample. When Graphene oxide nanocolloids, a nanomaterial, were added, the refractive index decreased with increasing amount of Graphene oxide nanocolloids from 1.4209 to 13959. In the case of water content, the sample with 5% Hyaluronic acid and MA added slightly increased to 41.01%. In the case of Graphene oxide nanocolloids added, 48.76%~53.56% of Graphene oxide nanocolloids were added. Especially, it was observed that the water content increased sharply in the 0.1% sample of Graphene oxide nanocolloids. When the amount of graphene oxide nanocolloids added to the contact lens material was increased, the refractive index, which is a basic physical property, gradually decreased as the contact lens material was added together with Hyaluronic acid, MA, and Graphene oxide nanocolloids added as a nanomaterial. The water content tended to increase gradually. Therefore, the combination of Graphene oxide and hydrophilicmaterials shows a synergistic effect of physical properties, which is considered to be suitable as a material for contact lenses.

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Mikhailov, Sergey A. « Nonlinear Electrodynamic and Optical Properties of Graphene ». Advanced Materials Research 324 (août 2011) : 237–40. http://dx.doi.org/10.4028/www.scientific.net/amr.324.237.

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Graphene is a recently discovered new material with unique physical properties. In this paper we discuss its electrodynamic and optical properties. It is shown that the electromagnetic response of graphene to the external radiation is strongly nonlinear and such phenomena as the frequency harmonics generation and frequency mixing effects can be observed in it. The nonlinear susceptibility of graphene is higher than that of many other materials.We predict that under certain conditions the plasmon enhanced second harmonic generation can be observed in graphene.

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Hosseingholipourasl, Ali, Sharifah Hafizah Syed Ariffin, Yasser D. Al-Otaibi, Elnaz Akbari, Fatimah KH Hamid, S. S. R. Koloor et Michal Petrů. « Analytical Approach to Study Sensing Properties of Graphene Based Gas Sensor ». Sensors 20, n^o 5 (9 mars 2020) : 1506. http://dx.doi.org/10.3390/s20051506.

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Over the past years, carbon-based materials and especially graphene, have always been known as one of the most famous and popular materials for sensing applications. Graphene poses outstanding electrical and physical properties that make it favorable to be used as a transducer in the gas sensors structure. Graphene experiences remarkable changes in its physical and electrical properties when exposed to various gas molecules. Therefore, in this study, a set of new analytical models are developed to investigate energy band structure, the density of states (DOS), the velocity of charged carriers and I-V characteristics of the graphene after molecular (CO, NO2, H2O) adsorption. The results show that gas adsorption modulates the energy band structure of the graphene that leads to the variation of the energy bandgap, thus the DOS changes. Consequently, graphene converts to semiconducting material, which affects the graphene conductivity and together with the DOS variation, modulate velocity and I-V characteristics of the graphene. These parameters are important factors that can be implemented as sensing parameters and can be used to analyze and develop new sensors based on graphene material.

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Chen, Yanyan, Jie Sun, Wei Kang et Qian Wang. « Phonon Transport and Thermoelectric Properties of Imidazole-Graphyne ». Materials 14, n^o 19 (27 septembre 2021) : 5604. http://dx.doi.org/10.3390/ma14195604.

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The pentagon has been proven to be an important structural unit for carbon materials, leading to different physical and chemical properties from those of hexagon-based allotropes. Following the development from graphene to penta-graphene, a breakthrough has very recently been made for graphyne—for example, imidazole-graphyne (ID-GY) was formed by assembling experimentally synthesized pentagonal imidazole molecules and acetylenic linkers. In this work, we study the thermal properties and thermoelectric performance of ID-GY by combining first principle calculations with the Boltzmann transport theory. The calculated lattice thermal conductivity of ID-GY is 10.76 W/mK at 300 K, which is only one tenth of that of γ-graphyne (106.24 W/mK). A detailed analysis of the harmonic and anharmonic properties, including the phonon group velocity, phonon lifetime, atomic displacement parameter, and bond energy curves, reveals that the low lattice thermal conductivity can be attributed to the low Young’s modulus, low Debye temperature, and high Grüneisen parameter. Furthermore, at room temperature, ID-GY can reach a high ZT value of 0.46 with a 5.8 × 1012 cm−2 hole concentration, which is much higher than the value for many other carbon-based materials. This work demonstrates that changing structural units from hexagonal to pentagonal can significantly reduce the lattice thermal conductivity and enhance the thermoelectric performance of carbon-based materials.

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IONI, Yulia V. « NANOPARTICLES OF NOBLE METALS ON THE SURFACE OF GRAPHENE FLAKES ». Periódico Tchê Química 17, n^o 36 (20 décembre 2020) : 1199–211. http://dx.doi.org/10.52571/ptq.v17.n36.2020.1215_periodico36_pgs_1199_1211.pdf.

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Carbon is a spread element that has many different reaction combinations. Obtaining new composite materials based on nanoparticles is a very actual and perspective topic because nanoparticles possess unique properties. These properties are retained and even amplified when nanoparticles are located in various matrixes. Furthermore, nowadays, the creation of graphene-based composites and graphene-related structures is a promising area of synthesis of composite nanomaterials. Previous research has determined that graphene has a unique set of electrophysical, thermal, optical, and mechanical properties. In this study, the synthesis of nanocomposites representing nanoparticles of noble metals (Au, Pd, Rh) on the surface of graphene flakes were carried out, and the study of their composition, structure, physical and chemical properties, and possible applications in catalysis. The immobilization of nanoparticles on the surface of graphene oxide and graphene was developed, and the original method of synthesis of nanocomposite noble metal nanoparticles on the graphene flakes surface using supercritical isopropanol as a reduction agent for the transformation of graphene oxide into graphene was created. The study of physical and chemical properties of the obtained nanocomposites and results of the study of obtained nanocomposites as catalysts for model organic reactions of cross-coupling and hydroformylation showed that it is possible to create the graphene-based nanostructures as effective functional nanomaterials. Research on the synthesis of graphene compounds and its unique physical properties form a promising direction in the chemistry and physics of new inorganic functional materials. The resulting nanocomposites can be used in such branches as electrodes for LEDs and solar cells, field-effect transistors, supercapacitors, sensors, fuel cells.

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Bensam, Raj, et M. Muthuraj. « Influence of graphene nano-platelets dispersion on the thermo-physical properties of sunflower oil ». Chemical Industry and Chemical Engineering Quarterly, n^o 00 (2021) : 18. http://dx.doi.org/10.2298/ciceq210101018b.

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In this article, thermal stability, viscosity, density and surface tension of Graphene nano-platelets dispersed sunflower oil are experimentally determined by varying the Graphene concentration (0.1-1.1wt%) and temperature (40-100?C). The SEM micrograph and the EDS spectra are used to characterize the Graphene. Nanofluids are prepared by ultrasonication technique (two-step method) and the maximum thermal stability of about 280?C is achieved at 1.1wt% Graphene nanofluids. The dynamic viscosity diminished in an exponential shape in acquiescence with Arrhenius equation and the densities of samples are characteristic with linear decrement in the estimated temperature range. Density and surface tension increases with the Graphene concentration, while a reverse trend is observed with temperature rise. The maximum thermal stability, viscosity, density and surface tension is obtained in the nanofluid with 1.1 wt% concentration and the minimum is obtained in the nanofluid with 0.1 wt% concentration.

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Yang, Jun, Julietraja Konsalraj et Arul Amirtha Raja Raja S. « Neighbourhood Sum Degree-Based Indices and Entropy Measures for Certain Family of Graphene Molecules ». Molecules 28, n^o 1 (25 décembre 2022) : 168. http://dx.doi.org/10.3390/molecules28010168.

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A topological index (TI) is a real number that defines the relationship between a chemical structure and its properties and remains invariant under graph isomorphism. TIs defined for chemical structures are capable of predicting physical properties, chemical reactivity and biological activity. Several kinds of TIs have been defined and studied for different molecular structures. Graphene is the thinnest material known to man and is also extremely strong while being a good conductor of heat and electricity. With such unique features, graphene and its derivatives have found commercial uses and have also fascinated theoretical chemists. In this article, the neighbourhood sum degree-based M-polynomial and entropy measures have been computed for graphene, graphyne and graphdiyne structures. The proper analytical expressions for these indices are derived. The obtained results will enable theoretical chemists to study these exciting structures further from a structural perspective.

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Lee, Se Jung, Seo Jeong Yoon et In-Yup Jeon. « Graphene/Polymer Nanocomposites : Preparation, Mechanical Properties, and Application ». Polymers 14, n^o 21 (4 novembre 2022) : 4733. http://dx.doi.org/10.3390/polym14214733.

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Although polymers are very important and vastly used materials, their physical properties are limited. Therefore, they are reinforced with fillers to relieve diverse restrictions and expand their application areas. The exceptional properties of graphene make it an interesting material with huge potential for application in various industries and devices. The interfacial interaction between graphene and the polymer matrix improved the uniform graphene dispersion in the polymer matrix, enhancing the general nanocomposite performance. Therefore, graphene functionalization is essential to enhance the interfacial interaction, maintain excellent properties, and obstruct graphene agglomeration. Many studies have reported that graphene/polymer nanocomposites have exceptional properties that enable diverse applications. The use of graphene/polymer nanocomposites is expected to increase sustainably and to transform from a basic to an advanced material to offer optimum solutions to industry and consumers.

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Forati, T., M. Atai, A. M. Rashidi, M. Imani et A. Behnamghader. « Physical and mechanical properties of graphene oxide/polyethersulfone nanocomposites ». Polymers for Advanced Technologies 25, n^o 3 (27 décembre 2013) : 322–28. http://dx.doi.org/10.1002/pat.3243.

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Hills, Romilly D. Y., et Feodor V. Kusmartsev. « Physical properties of Zener tunnelling nano-devices in graphene ». Annalen der Physik 526, n^o 9-10 (octobre 2014) : 437–48. http://dx.doi.org/10.1002/andp.201400147.

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Khan, Aftab A., Eraj H. Mirza, Badreldin A. Mohamed, Nabeel H. Alharthi, Hany S. Abdo, Ravish Javed, Rashed S. Alhur et Pekka K. Vallittu. « Physical, mechanical, chemical and thermal properties of nanoscale graphene oxide-poly methylmethacrylate composites ». Journal of Composite Materials 52, n^o 20 (24 janvier 2018) : 2803–13. http://dx.doi.org/10.1177/0021998318754642.

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The purpose of this laboratory study was to formulate and characterize the graphene oxide-poly(methyl methacrylate) resin composite with an intended use as bone cement. Graphene oxide was fabricated through ultrasonication route. The autopolymerization resin (Eco Cryl Cold, Protechno, Vilamalla Girona, Spain) was used to prepare the specimens of required dimensions for different testing parameters. The control group (C-group) was prepared as such. However, for GO1-group, 0.024 wt/wt.-% of graphene oxide was incorporated in a resin matrix and GO2-group was a composite with 0.048 wt/wt.-% of graphene oxide in a resin matrix. TEM examination of graphene oxide sheets demonstrated them in the range of ∼500 nm to ∼2 µm. The mechanical properties were characterized using three-point bending and wear resistance, while material properties were assessed through transmission electron microscope, scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry and thermo-gravimetric analysis. The results suggest that 0.024 wt/wt.-% and 0.048 wt/wt.-% of loading of GO have no effect on the physiochemical characteristics. However, thermal characteristics might slightly be improved. According to the analysis of variance results ( p < 0.05, n = 5), wear resistance and bending strength of both GO1 and GO2 groups significantly improved compared to C-group. The bending strength of GO2 improved to 87.0 ± 7.2 MPa from 65.9 ± 11.5 MPa of C-group. Scanning electron microscopy examination of the fractured surface demonstrated granule like structure where the graphene oxide sheets might be covered inside PMMA. The use of GO-PMMA composites favorably enhances the mechanical properties of bone cement.

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Wu, Ying, Chao An et Yaru Guo. « 3D Printed Graphene and Graphene/Polymer Composites for Multifunctional Applications ». Materials 16, n^o 16 (18 août 2023) : 5681. http://dx.doi.org/10.3390/ma16165681.

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Three-dimensional (3D) printing, alternatively known as additive manufacturing, is a transformative technology enabling precise, customized, and efficient manufacturing of components with complex structures. It revolutionizes traditional processes, allowing rapid prototyping, cost-effective production, and intricate designs. The 3D printed graphene-based materials combine graphene’s exceptional properties with additive manufacturing’s versatility, offering precise control over intricate structures with enhanced functionalities. To gain comprehensive insights into the development of 3D printed graphene and graphene/polymer composites, this review delves into their intricate fabrication methods, unique structural attributes, and multifaceted applications across various domains. Recent advances in printable materials, apparatus characteristics, and printed structures of typical 3D printing techniques for graphene and graphene/polymer composites are addressed, including extrusion methods (direct ink writing and fused deposition modeling), photopolymerization strategies (stereolithography and digital light processing) and powder-based techniques. Multifunctional applications in energy storage, physical sensor, stretchable conductor, electromagnetic interference shielding and wave absorption, as well as bio-applications are highlighted. Despite significant advancements in 3D printed graphene and its polymer composites, innovative studies are still necessary to fully unlock their inherent capabilities.

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Lee, Junghyun, Jihyung Seo, Sungchul Jung, Kibog Park et Hyesung Park. « Unveiling the Direct Correlation between the CVD-Grown Graphene and the Growth Template ». Journal of Nanomaterials 2018 (19 août 2018) : 1–6. http://dx.doi.org/10.1155/2018/7610409.

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Chemical vapor deposition (CVD) is known to produce continuous, large-area graphene sheet with decent physical properties. In the CVD process, catalytic metal substrates are typically used as the growth template, and copper has been adopted as the representative material platform due to its low carbon solubility and resulting monolayer graphene growth capability. For the widespread industrial applications of graphene, achieving the high-quality is essential. Several factors affect the qualities of CVD-grown graphene, such as pressure, temperature, carbon precursors, or growth template. In this work, we provide detailed analysis on the direct relation between the metallic growth substrate (copper) and overall properties of the resulting CVD-grown graphene. The surface morphology of copper substrate was modulated via simple chemical treatments, and its effect on physical, optical, and electrical properties of graphene was analyzed. Based on these results, we propose a simple synthesis route to produce high-quality, continuous, monolayer graphene sheet, which can facilitate the commercialization of CVD graphene into reality.

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Luo, Ling Ling, Xing Xing Gu, Jun Wu, Shu Xian Zhong et Jian Rong Chen. « Advances in Graphene for Adsorption of Heavy Metals in Wastewater ». Advanced Materials Research 550-553 (juillet 2012) : 2121–24. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2121.

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Graphene for its unique physical structure, excellent mechanical, electrical and physical properties has been widely applied in nanoelectronics, microelectronics, energy storage material, composite materials and so on. In recent years, many researchers found graphene have outstanding adsorption capacity of contaminants in aqueous solution due to its high specific surface area. This paper summarized the graphene, graphene oxide and functionalized graphene removing various heavy metals in waste water.

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Alfonso, Jose Edgar, et John Jairo Olaya. « Influence of Ag nanoparticles on the physical properties of multilayers of graphene ». DYNA 86, n^o 211 (1 octobre 2019) : 49–53. http://dx.doi.org/10.15446/dyna.v86n211.74812.

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Graphene has attracted considerable interest due its exceptional physical properties. This article describes the thermoelectric and magnetic properties such as the Seebeck coefficient and the magnetoresistance, at room temperature, of multilayers of graphene fabricated through the chemical vapor deposition (CVD) method and coated with Ag nanoparticles (NPs). According to the results, the Seebeck coefficient increased from -30 to -5 μV/K as a function of deposition time of Ag NPsand magnetoresistance increase their initial value as a function of sheet resistance up to 16.6%.

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Alekhina, R. A., et V. E. Slavkina. « REVIEW OF THE PHYSICAL AND MECHANICAL CHARACTERISTICS OF POLYURETHANE NANOCOMPOSITES ». IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, n^o 12(259) (21 décembre 2021) : 23–31. http://dx.doi.org/10.35211/1990-5297-2021-12-259-23-31.

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Polyurethane nanocomposites are promising materials in many industries, they have superior physical and mechanical properties compared to the original polyurethane. This paper presents an analysis of the physical and mechanical properties of polyurethane nano-composites with various types of fillers such as organoclays, carbon nanotubes, polyhedral oligomeric silse-squioxanes, graphene, graphene oxide, polytetrafluoroethylene, and metal nanoparticles. The concentration-dependent effects in changing the structure and properties of polyurethane composites under the influence of the added fillers were also considered. It is noted that the values of physical and mechanical properties are influenced by the uniform distribution of nanofiller particles in the composite and their chemical modification. It was found that with a uniform distribution of nanoparticles in the polymer matrix, the physicomechanical properties of the resulting composites increase.

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Voloshina, Elena N., et Yuriy S. Dedkov. « Electronic and Magnetic Properties of the Graphene/Eu/Ni(111) Hybrid System ». Zeitschrift für Naturforschung A 69, n^o 7 (1 juillet 2014) : 297–302. http://dx.doi.org/10.5560/zna.2014-0012.

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The electronic and magnetic properties of the graphene/Eu/Ni(111) intercalation-like system are studied in the framework of the general gradient approximation with the effective Coulomb potential (GGA+U) and dispersive interactions taken into account. Intercalation of monoatomic europium layer underneath graphene on Ni(111) leads to the drastic changes of the electronic structure of graphene compared to free-standing graphene as well as graphene/Ni(111). The strong influence of the spin-polarized europium 4 f states, crossing the graphene-derived π states, on magnetic properties of graphene and on spin-filtering properties of the graphene/Eu/Ni(111) trilayer is discussed.

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Alawi, Omer A., Nor Azwadi Che Sidik, S. N. Kazi et G. Najafi. « Graphene nanoplatelets and few-layer graphene studies in thermo-physical properties and particle characterization ». Journal of Thermal Analysis and Calorimetry 135, n^o 2 (2 août 2018) : 1081–93. http://dx.doi.org/10.1007/s10973-018-7585-0.

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Kumar, Parveen, Peipei Huo, Rongzhao Zhang et Bo Liu. « Antibacterial Properties of Graphene-Based Nanomaterials ». Nanomaterials 9, n^o 5 (13 mai 2019) : 737. http://dx.doi.org/10.3390/nano9050737.

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Bacteria mediated infections may cause various acute or chronic illnesses and antibiotic resistance in pathogenic bacteria has become a serious health problem around the world due to their excessive use or misuse. Replacement of existing antibacterial agents with a novel and efficient alternative is the immediate demand to alleviate this problem. Graphene-based materials have been exquisitely studied because of their remarkable bactericidal activity on a wide range of bacteria. Graphene-based materials provide advantages of easy preparation, renewable, unique catalytic properties, and exceptional physical properties such as a large specific surface area and mechanical strength. However, several queries related to the mechanism of action, significance of size and composition toward bacterial activity, toxicity criteria, and other issues are needed to be addressed. This review summarizes the recent efforts that have been made so far toward the development of graphene-based antibacterial materials to face current challenges to combat against the bacterial targets. This review describes the inherent antibacterial activity of graphene-family and recent advances that have been made on graphene-based antibacterial materials covering the functionalization with silver nanoparticles, other metal ions/oxides nanoparticles, polymers, antibiotics, and enzymes along with their multicomponent functionalization. Furthermore, the review describes the biosafety of the graphene-based antibacterial materials. It is hoped that this review will provide valuable current insight and excite new ideas for the further development of safe and efficient graphene-based antibacterial materials.

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Kosowska, Katarzyna, Jan Krzysztoforski et Marek Henczka. « Foaming of PCL-Based Composites Using scCO2 : Structure and Physical Properties ». Materials 15, n^o 3 (3 février 2022) : 1169. http://dx.doi.org/10.3390/ma15031169.

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The process of foaming poly(caprolactone)-based composites using supercritical carbon dioxide was analyzed. The impact of the conditions of the solid-foam production process on the process efficiency and properties of porous structures was investigated. The novel application of various types of porogens—hydroxyapatite, nanocellulose, carboxymethylcellulose, and graphene oxide—was tested in order to modify the properties and improve the quality of solid foams, increasing their usefulness in specialized practical applications. The study showed a significant influence of the foaming process conditions on the properties of solid foams. The optimal process parameters were determined to be pressure 18 MPa, temperature 70 °C, and time 1 h in order to obtain structures with appropriate properties for applications in biomedical engineering, and the most promising material for their production was selected: a composite containing 5% hydroxyapatite or 0.2% graphene oxide.

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Cho, Byungjin, et Yonghun Kim. « Preparation and Properties of 2D Materials ». Nanomaterials 10, n^o 4 (16 avril 2020) : 764. http://dx.doi.org/10.3390/nano10040764.

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Since the great success of graphene, atomically thin layered nanomaterials—called two-dimensional (2D) materials—have attracted tremendous attention due to their extraordinary physical properties [...]

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Firdaus, Rabita Mohd, Alexandre Desforges, Mélanie Emo, Abdul Rahman Mohamed et Brigitte Vigolo. « Physical and Chemical Activation of Graphene-Derived Porous Nanomaterials for Post-Combustion Carbon Dioxide Capture ». Nanomaterials 11, n^o 9 (17 septembre 2021) : 2419. http://dx.doi.org/10.3390/nano11092419.

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Activation is commonly used to improve the surface and porosity of different kinds of carbon nanomaterials: activated carbon, carbon nanotubes, graphene, and carbon black. In this study, both physical and chemical activations are applied to graphene oxide by using CO2 and KOH-based approaches, respectively. The structural and the chemical properties of the prepared activated graphene are deeply characterized by means of scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry and nitrogen adsorption. Temperature activation is shown to be a key parameter leading to enhanced CO2 adsorption capacity of the graphene oxide-based materials. The specific surface area is increased from 219.3 m2 g−1 for starting graphene oxide to 762.5 and 1060.5 m2 g−1 after physical and chemical activation, respectively. The performance of CO2 adsorption is gradually enhanced with the activation temperature for both approaches: for the best performances of a factor of 6.5 and 9 for physical and chemical activation, respectively. The measured CO2 capacities are of 27.2 mg g−1 and 38.9 mg g−1 for the physically and chemically activated graphene, respectively, at 25 °C and 1 bar.

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Zhang, Xiuli, Guangming He, Hui Yao, Xuanxi Wang, Guoru Ma, Junliang Li, Zulong Yu, Guozhong Lu et Zhifei Gao. « Effect of graphene on the properties of epoxy in hygrothermal environment by molecular dynamics method ». Electronic Research Archive 31, n^o 6 (2023) : 3510–33. http://dx.doi.org/10.3934/era.2023178.

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<abstract> <p>The physical and mechanical properties of graphene-reinforced epoxy (epoxy/graphene) in hygrothermal environment need to be comprehensively understood. This is because it is necessary to predict the durability of epoxy/graphene when epoxy/graphene is used in an aggressive environment with high humidity and high temperature. Based on the molecular dynamics method, the influences of water content (2, 4 and 6%) and temperature (298,333 and 368 K) on the physical and tensile properties of epoxy/graphene were studied in this research. The results showed that after the addition of graphene, the free volume fraction of epoxy and the diffusion coefficient of water molecules in the epoxy decreased, and the density, tensile strength and deformation performance of epoxy increased. In the hygrothermal environment, the tensile strength degradation rate of epoxy/graphene was lower than that of pure epoxy. The failure mechanism and mechanical response of epoxy/graphene during the tensile process in the nanoscale were revealed. The research results provide a reference for the design and performance optimization of epoxy/graphene composites in a hygrothermal environment.</p> </abstract>

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Bartczak, Natalia, Jerzy Kowalczyk, Robert Tomala, Mariusz Stefanski, Damian Szymański, Maciej Ptak, Wiesław Stręk et al. « Effect of the Addition of Graphene Flakes on the Physical and Biological Properties of Composite Paints ». Molecules 28, n^o 16 (21 août 2023) : 6173. http://dx.doi.org/10.3390/molecules28166173.

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In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices. The mechanical properties were evaluated using micro-hardness testing, while wettability and antimicrobial activity against three pathogens (Staphylococcus aureus 33591, Pseudomonas aeruginosa 15442, Candida albicans 10231) were also examined. The results indicate that the addition of graphene flakes significantly enhances both the mechanical and antimicrobial properties of the coatings.

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Fujii, Shintaro, Maxim Ziatdinov, Misako Ohtsuka, Koichi Kusakabe, Manabu Kiguchi et Toshiaki Enoki. « Role of edge geometry and chemistry in the electronic properties of graphene nanostructures ». Faraday Discuss. 173 (2014) : 173–99. http://dx.doi.org/10.1039/c4fd00073k.

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The geometry and chemistry of graphene nanostructures significantly affects their electronic properties. Despite a large number of experimental and theoretical studies dealing with the geometrical shape-dependent electronic properties of graphene nanostructures, experimental characterisation of their chemistry is clearly lacking. This is mostly due to the difficulties in preparing chemically-modified graphene nanostructures in a controlled manner and in identifying the exact chemistry of the graphene nanostructure on the atomic scale. Herein, we present scanning probe microscopic and first-principles characterisation of graphene nanostructures with different edge geometries and chemistry. Using the results of atomic scale electronic characterisation and theoretical simulation, we discuss the role of the edge geometry and chemistry on the electronic properties of graphene nanostructures with hydrogenated and oxidised linear edges at graphene boundaries and the internal edges of graphene vacancy defects. Atomic-scale details of the chemical composition have a strong impact on the electronic properties of graphene nanostructures,i.e., the presence or absence of non-bonding π states and the degree of resonance stability.

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Sahu, Dibyani, Harekrushna Sutar, Pragyan Senapati, Rabiranjan Murmu et Debashis Roy. « Graphene, Graphene-Derivatives and Composites : Fundamentals, Synthesis Approaches to Applications ». Journal of Composites Science 5, n^o 7 (9 juillet 2021) : 181. http://dx.doi.org/10.3390/jcs5070181.

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Graphene has accomplished huge notoriety and interest from the universe of science considering its exceptional mechanical physical and thermal properties. Graphene is an allotrope of carbon having one atom thick size and planar sheets thickly stuffed in a lattice structure resembling a honeycomb structure. Numerous methods to prepare graphene have been created throughout a limited span of time. Due to its fascinating properties, it has found some extensive applications to a wide variety of fields. So, we believe there is a necessity to produce a document of the outstanding methods and some of the novel applications of graphene. This article centres around the strategies to orchestrate graphene and its applications in an attempt to sum up the advancements that has taken place in the research of graphene.

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Li, Zongwen, Wenfei Zhang et Fei Xing. « Graphene Optical Biosensors ». International Journal of Molecular Sciences 20, n^o 10 (18 mai 2019) : 2461. http://dx.doi.org/10.3390/ijms20102461.

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Graphene shows great potential in biosensing owing to its extraordinary optical, electrical and physical properties. In particular, graphene possesses unique optical properties, such as broadband and tunable absorption, and strong polarization-dependent effects. This lays a foundation for building graphene-based optical sensors. This paper selectively reviews recent advances in graphene-based optical sensors and biosensors. Graphene-based optical biosensors can be used for single cell detection, cell line, and anticancer drug detection, protein and antigen–antibody detection. These new high-performance graphene-based optical sensors are able to detect surface structural changes and biomolecular interactions. In all these cases, the optical biosensors perform well with ultra-fast detection, high sensitivities, unmarked, and are able to respond in real time. The future of the field of graphene applications is also discussed.

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