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Kotsidi M, Gorgolis G, Pastore Carbone MG, Paterakis G, Anagnostopoulos G, Trakakis G, Manikas AC, Pavlou C, Koutroumanis N, Galiotis C. Graphene nanoplatelets and other 2D-materials as protective means against the fading of coloured inks, dyes and paints. Nanoscale 2023; 15:5414-5428. [PMID: 36826806 PMCID: PMC10019573 DOI: 10.1039/d2nr05795f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
The present work demonstrates the ability of graphene nanoplatelets (GNPs) and other two-dimensional materials (2DMs) like tungsten disulfide (WS2), molybdenum disulfide (MoS2) and hexagonal boron nitride (hBN) to act as protective barriers against the fading of architectural paints and also inks/paints used in art. The results present a new approach for improving the lightfastness of colours of artworks and painted indoor/outdoor wall surfaces taking advantage of the remarkable properties of 2DMs. As shown herein, commercial inks and architectural paints of different colours doped with graphene nanoplatelets (GNPs), graphene oxide (GO), reduced graphene oxide (rGO) and other 2DMs, exhibit a superior resistance to fading under ultraviolet radiation or even under exposure to visible light. A spectroscopic study on these inks and dyes reveals that the peaks which are characteristic of the colour pigments are less affected from aging/fading when the GNPs and the other 2DMs are present. The protection mechanism for the GNPs and the other 2DMs differs. For GNPs, mainly their high surface area which leads to free radicals scavenging (especially hydroxyl radicals), and secondarily their UV absorption, are responsible for their protection effects, while for GO, a transition to rGO structures and consequently to 'smart' paints can be observed after the performed aging routes. In this way, the paint gets improved by time preventing or slowing its own fading and decolorization. For the other 2DMs, the transition-metal dichalcogenides performed better than hBN, even though they all absorb in the UV region. This can be ascribed to the facts that the formers also absorb in the visible, while hBN does not, while most importantly, they can trap reactive oxygen species (ROS) and corrosive gases in their structure as opposed to hBN. By conducting colorimetric measurements, we have discovered that the lifetime of the as-developed 2DM-doped inks and paints can be extended by up to ∼40%.
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Affiliation(s)
- M Kotsidi
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
- Department of Chemical Engineering, University of Patras, Patras 26504, Greece
| | - G Gorgolis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
- Department of Chemical Engineering, University of Patras, Patras 26504, Greece
| | - M G Pastore Carbone
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
| | - G Paterakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
| | - G Anagnostopoulos
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
| | - G Trakakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
| | - A C Manikas
- Department of Chemical Engineering, University of Patras, Patras 26504, Greece
| | - C Pavlou
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
| | - N Koutroumanis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
| | - C Galiotis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ICE-HT), Patras 265 04, Greece.
- Department of Chemical Engineering, University of Patras, Patras 26504, Greece
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Dimitropoulos M, Trakakis G, Meyerbröker N, Gehra R, Angelova P, Schnieders A, Pavlou C, Kostaras C, Galiotis C, Dassios K. Nanomechanics of Ultrathin Carbon Nanomembranes. Nanomaterials (Basel) 2023; 13:267. [PMID: 36678021 PMCID: PMC9863011 DOI: 10.3390/nano13020267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Ultrathin carbon nanomembranes (CNMs) are two-dimensional materials (2DM) of a few nm thickness with sub-nm intrinsic pores that mimic the biofiltration membranes found in nature. They enable highly selective, permeable, and energy-efficient water separation and can be produced at large scales on porous substrates with tuned properties. The present work reports the mechanical performance of such CNMs produced by p-nitrobiphenyl phosphonic acid (NBPS) or polyvinylbiphenyl (PVBP) and their composite membranes of microporous supporting substrates, which constitute indispensable information for ensuring their mechanical stability during operation. Measuring the nanomechanical properties of the ultrathin material was achieved by atomic force microscopy (AFM) on membranes both supported on flat substrates and suspended on patterned substrates ("composite membrane"). The AFM analysis showed that the CNMs presented Young's modulus in the range of 2.5-8 GPa. The composite membranes' responses were investigated by tensile testing in a micro-tensile stage as a function of substrate thickness and substrate pore density and diameter, which were found to affect the mechanical properties. Thermogravimetric analysis was used to investigate the thermal stability of composite membranes at high temperatures. The results revealed the structural integrity of CNMs, while critical parameters governing their mechanical response were identified and discussed.
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Affiliation(s)
- Marinos Dimitropoulos
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE–HT), Foundation of Research and Technology Hellas, GR-26504 Patras, Greece
| | - George Trakakis
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE–HT), Foundation of Research and Technology Hellas, GR-26504 Patras, Greece
| | | | - Raphael Gehra
- CNM Technologies GmbH, Morgenbreede 1, 33615 Bielefeld, Germany
| | - Polina Angelova
- CNM Technologies GmbH, Morgenbreede 1, 33615 Bielefeld, Germany
| | | | - Christos Pavlou
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE–HT), Foundation of Research and Technology Hellas, GR-26504 Patras, Greece
| | - Christos Kostaras
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE–HT), Foundation of Research and Technology Hellas, GR-26504 Patras, Greece
| | - Costas Galiotis
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE–HT), Foundation of Research and Technology Hellas, GR-26504 Patras, Greece
| | - Konstantinos Dassios
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE–HT), Foundation of Research and Technology Hellas, GR-26504 Patras, Greece
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Dimitropoulos M, Trakakis G, Androulidakis C, Kotsidi M, Galiotis C. Wrinkle-mediated CVD synthesis of wafer scale Graphene/h-BN heterostructures. Nanotechnology 2022; 34:025601. [PMID: 36215949 DOI: 10.1088/1361-6528/ac98d0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The combination of two-dimensional materials (2D) into heterostructures enables their integration in tunable ultrathin devices. For applications in electronics and optoelectronics, direct growth of wafer-scale and vertically stacked graphene/hexagonal boron nitride (h-BN) heterostructures is vital. The fundamental problem, however, is the catalytically inert nature of h-BN substrates, which typically provide a low rate of carbon precursor breakdown and consequently a poor rate of graphene synthesis. Furthermore, out-of-plane deformations such as wrinkles are commonly seen in 2D materials grown by chemical vapor deposition (CVD). Herein, a wrinkle-facilitated route is developed for the fast growth of graphene/h-BN vertical heterostructures on Cu foils. The key advantage of this synthetic pathway is the exploitation of the increased reactivity from inevitable line defects arising from the CVD process, which can act as active sites for graphene nucleation. The resulted heterostructures are found to exhibit superlubric properties with increased bending stiffness, as well as directional electronic properties, as revealed from atomic force microscopy measurements. This work offers a brand-new route for the fast growth of Gr/h-BN heterostructures with practical scalability, thus propelling applications in electronics and nanomechanical systems.
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Affiliation(s)
- Marinos Dimitropoulos
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE-HT), Foundation of Research and Technology Hellas, PO Box 1414, GR-26504 Patras, Greece
| | - George Trakakis
- Institute of Chemical Engineering Sciences (ICE-HT), Foundation of Research and Technology Hellas, PO Box 1414, GR-26504 Patras, Greece
| | - Charalampos Androulidakis
- Institute of Chemical Engineering Sciences (ICE-HT), Foundation of Research and Technology Hellas, PO Box 1414, GR-26504 Patras, Greece
| | - Maria Kotsidi
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE-HT), Foundation of Research and Technology Hellas, PO Box 1414, GR-26504 Patras, Greece
| | - Costas Galiotis
- Department of Chemical Engineering, University of Patras, GR-26500 Patras, Greece
- Institute of Chemical Engineering Sciences (ICE-HT), Foundation of Research and Technology Hellas, PO Box 1414, GR-26504 Patras, Greece
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Kotsidi M, Gorgolis G, Pastore Carbone MG, Anagnostopoulos G, Paterakis G, Poggi G, Manikas A, Trakakis G, Baglioni P, Galiotis C. Preventing colour fading in artworks with graphene veils. Nat Nanotechnol 2021; 16:1004-1010. [PMID: 34211165 DOI: 10.1038/s41565-021-00934-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Modern and contemporary art materials are generally prone to irreversible colour changes upon exposure to light and oxidizing agents. Graphene can be produced in thin large sheets, blocks ultraviolet light, and is impermeable to oxygen, moisture and corrosive agents; therefore, it has the potential to be used as a transparent layer for the protection of art objects in museums, during storage and transportation. Here we show that a single-layer or multilayer graphene veil, produced by chemical vapour deposition, can be deposited over artworks to protect them efficiently against colour fading, with a protection factor of up to 70%. We also show that this process is reversible since the graphene protective layer can be removed using a soft rubber eraser without causing any damage to the artwork. We have also explored a complementary contactless graphene-based route for colour protection that is based on the deposition of graphene on picture framing glass for use when the direct application of graphene is not feasible due to surface roughness or artwork fragility. Overall, the present results are a proof of concept of the potential use of graphene as an effective and removable protective advanced material to prevent colour fading in artworks.
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Affiliation(s)
- M Kotsidi
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
- Department of Chemical Engineering, University of Patras, Patras, Greece
| | - G Gorgolis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - M G Pastore Carbone
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - G Anagnostopoulos
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - G Paterakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
- Department of Chemical Engineering, University of Patras, Patras, Greece
| | - G Poggi
- CSGI & Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - A Manikas
- Department of Chemical Engineering, University of Patras, Patras, Greece
| | - G Trakakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece
| | - P Baglioni
- CSGI & Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - C Galiotis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas (FORTH/ ICE-HT), Patras, Greece.
- Department of Chemical Engineering, University of Patras, Patras, Greece.
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Pavlou C, Pastore Carbone MG, Manikas AC, Trakakis G, Koral C, Papari G, Andreone A, Galiotis C. Effective EMI shielding behaviour of thin graphene/PMMA nanolaminates in the THz range. Nat Commun 2021; 12:4655. [PMID: 34341360 PMCID: PMC8329220 DOI: 10.1038/s41467-021-24970-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 06/24/2021] [Indexed: 11/09/2022] Open
Abstract
The use of graphene in a form of discontinuous flakes in polymer composites limits the full exploitation of the unique properties of graphene, thus requiring high filler loadings for achieving- for example- satisfactory electrical and mechanical properties. Herein centimetre-scale CVD graphene/polymer nanolaminates have been produced by using an iterative ‘lift-off/float-on’ process and have been found to outperform, for the same graphene content, state-of-the-art flake-based graphene polymer composites in terms of mechanical reinforcement and electrical properties. Most importantly these thin laminate materials show a high electromagnetic interference (EMI) shielding effectiveness, reaching 60 dB for a small thickness of 33 μm, and an absolute EMI shielding effectiveness close to 3·105 dB cm2 g−1 which is amongst the highest values for synthetic, non-metallic materials produced to date. The properties of graphene/polymer composites are usually limited by the use of discontinuous graphene flakes. Here, the authors report a fabrication method to realise continuous cm-scale graphene/polymer nanolaminates with enhanced electromagnetic interference shielding effectiveness, conductivity and mechanical properties.
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Affiliation(s)
- Christos Pavlou
- Foundation for Research and Technology Hellas, Institute of Chemical Engineering Sciences, Stadiou St. Platani, Patras, Greece.,Department of Chemical Engineering, University of Patras, Patras, Greece
| | - Maria Giovanna Pastore Carbone
- Foundation for Research and Technology Hellas, Institute of Chemical Engineering Sciences, Stadiou St. Platani, Patras, Greece
| | | | - George Trakakis
- Foundation for Research and Technology Hellas, Institute of Chemical Engineering Sciences, Stadiou St. Platani, Patras, Greece
| | | | - Gianpaolo Papari
- Department of Physics "E. Pancini", University of Naples "Federico II", Naples, Italy
| | - Antonello Andreone
- INFN Naples Unit, Naples, Italy.,Department of Physics "E. Pancini", University of Naples "Federico II", Naples, Italy
| | - Costas Galiotis
- Foundation for Research and Technology Hellas, Institute of Chemical Engineering Sciences, Stadiou St. Platani, Patras, Greece. .,Department of Chemical Engineering, University of Patras, Patras, Greece.
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Dalla PT, Tragazikis IK, Trakakis G, Galiotis C, Dassios KG, Matikas TE. Multifunctional Cement Mortars Enhanced with Graphene Nanoplatelets and Carbon Nanotubes. Sensors (Basel) 2021; 21:s21030933. [PMID: 33573281 PMCID: PMC7866800 DOI: 10.3390/s21030933] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 11/16/2022]
Abstract
Recent findings have brought forward the potential of carbon nano-species, especially nanotubes and graphene, to impart exceptional multifunctional potential to cement, offering simultaneous enhancement of mechanical, fracture mechanical and electrical properties. While available knowledge on the topic is still limited, there is a complete absence of direct comparisons of the potential of the nano-species to improve strength and toughness and provide multifunctionality to the mortars. The study offers a comprehensive overview of these potentials, for mortars modified with pure graphene nanoplatelets and carbon nanotubes at consistent, directly comparable, concentrations up to 1.2 wt.%. Testing included flexure under pure bending moments, axial compression, electrical resistivity measurements and fracture tests under three point bending configuration; the latter were also independently assessed by acoustic emission. Differences in documented properties and optimal concentrations associated with improved mechanical performance were directly compared and rationalized in terms of nanospecies morphology. Dramatic, statistically consistent improvements in fracture behavior, up to 10-fold of control values, were documented for specific nanofiller concentrations, indicating an excellent potential of the material system for contemporary smart construction applications. An exceptionally favorable comparison of acoustic emission and fracture energy data confirmed that the non-destructive technique can independently assess the fracture performance of mortars with exceptional precision.
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Affiliation(s)
- Panagiota T. Dalla
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; (P.T.D.); (I.K.T.); (T.E.M.)
| | - Ilias K. Tragazikis
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; (P.T.D.); (I.K.T.); (T.E.M.)
| | - George Trakakis
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas, (FORTH/ICE-HT), Stadiou Street, Platani, 26504 Patras, Greece; (G.T.); (C.G.)
| | - Costas Galiotis
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas, (FORTH/ICE-HT), Stadiou Street, Platani, 26504 Patras, Greece; (G.T.); (C.G.)
- Department of Chemical Engineering, Caratheodory 1, University of Patras, 26504 Patras, Greece
| | - Konstantinos G. Dassios
- Department of Chemical Engineering, Caratheodory 1, University of Patras, 26504 Patras, Greece
- Correspondence: ; Tel.: +30-261-099-6299
| | - Theodore E. Matikas
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; (P.T.D.); (I.K.T.); (T.E.M.)
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Trakakis G, Tomara G, Datsyuk V, Sygellou L, Bakolas A, Tasis D, Parthenios J, Krontiras C, Georga S, Galiotis C, Papagelis K. Mechanical, Electrical, and Thermal Properties of Carbon Nanotube Buckypapers/Epoxy Nanocomposites Produced by Oxidized and Epoxidized Nanotubes. Materials (Basel) 2020; 13:E4308. [PMID: 32992513 PMCID: PMC7579272 DOI: 10.3390/ma13194308] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022]
Abstract
High volume fraction carbon nanotube (CNT) composites (7.5-16% vol.) were fabricated by the impregnation of CNT buckypapers into epoxy resin. To enhance the interfacial reaction with the epoxy resin, the CNTs were modified by two different treatments, namely, an epoxidation treatment and a chemical oxidation. The chemical treatment was found to result in CNT length severance and to affect the porosity of the buckypapers, having an important impact on the physico-mechanical properties of the nanocomposites. Overall, the mechanical, electrical, and thermal properties of the impregnated buckypapers were found to be superior of the neat epoxy resin, offering an attractive combination of mechanical, electrical, and thermal properties for multifunctional composites.
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Affiliation(s)
- George Trakakis
- Foundation of Research and Technology Hellas, Institute of Chemical Engineering Sciences (ICE-HT), P.O. Box 1414, GR-26504 Patras, Greece; (G.T.); (L.S.); (J.P.); (C.G.)
| | - Georgia Tomara
- Department of Physics, University of Patras, 26504 Rio Patras, Greece; (G.T.); (C.K.); (S.G.)
| | - Vitaliy Datsyuk
- Physics Department, Institute of Experimental Physic, Free University Berlin, Arnimallee 14, 14195 Berlin, Germany;
| | - Labrini Sygellou
- Foundation of Research and Technology Hellas, Institute of Chemical Engineering Sciences (ICE-HT), P.O. Box 1414, GR-26504 Patras, Greece; (G.T.); (L.S.); (J.P.); (C.G.)
| | - Asterios Bakolas
- School of Chemical Engineering, National Technical University of Athens, GR-15773 Athens, Greece;
| | - Dimitrios Tasis
- Department of Chemistry (Section of Physical Chemistry), University of Ioannina, 45110 Ioannina, Greece;
| | - John Parthenios
- Foundation of Research and Technology Hellas, Institute of Chemical Engineering Sciences (ICE-HT), P.O. Box 1414, GR-26504 Patras, Greece; (G.T.); (L.S.); (J.P.); (C.G.)
| | - Christoforos Krontiras
- Department of Physics, University of Patras, 26504 Rio Patras, Greece; (G.T.); (C.K.); (S.G.)
| | - Stavroula Georga
- Department of Physics, University of Patras, 26504 Rio Patras, Greece; (G.T.); (C.K.); (S.G.)
| | - Costas Galiotis
- Foundation of Research and Technology Hellas, Institute of Chemical Engineering Sciences (ICE-HT), P.O. Box 1414, GR-26504 Patras, Greece; (G.T.); (L.S.); (J.P.); (C.G.)
- Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece
| | - Kostas Papagelis
- Foundation of Research and Technology Hellas, Institute of Chemical Engineering Sciences (ICE-HT), P.O. Box 1414, GR-26504 Patras, Greece; (G.T.); (L.S.); (J.P.); (C.G.)
- School of Physics, Department of Solid State Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Androulidakis C, Koukaras EN, Paterakis G, Trakakis G, Galiotis C. Tunable macroscale structural superlubricity in two-layer graphene via strain engineering. Nat Commun 2020; 11:1595. [PMID: 32221301 PMCID: PMC7101365 DOI: 10.1038/s41467-020-15446-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/04/2020] [Indexed: 11/10/2022] Open
Abstract
Achieving structural superlubricity in graphitic samples of macroscale size is particularly challenging due to difficulties in sliding large contact areas of commensurate stacking domains. Here, we show the presence of macroscale structural superlubricity between two randomly stacked graphene layers produced by both mechanical exfoliation and chemical vapour deposition. By measuring the shifts of Raman peaks under strain we estimate the values of frictional interlayer shear stress (ILSS) in the superlubricity regime (mm scale) under ambient conditions. The random incommensurate stacking, the presence of wrinkles and the mismatch in the lattice constant between two graphene layers induced by the tensile strain differential are considered responsible for the facile shearing at the macroscale. Furthermore, molecular dynamic simulations show that the stick-slip behaviour does not hold for incommensurate chiral shearing directions for which the ILSS decreases substantially, supporting the experimental observations. Our results pave the way for overcoming several limitations in achieving macroscale superlubricity using graphene.
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Affiliation(s)
- Charalampos Androulidakis
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas (FORTH/ICE-HT), Stadiou Street, Platani, Patras, 26504, Greece
| | - Emmanuel N Koukaras
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas (FORTH/ICE-HT), Stadiou Street, Platani, Patras, 26504, Greece
- Laboratory of Quantum and Computational Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, GR-54124, Thessaloniki, Greece
| | - George Paterakis
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas (FORTH/ICE-HT), Stadiou Street, Platani, Patras, 26504, Greece
- Department of Chemical Engineering, University of Patras, Patras, 26504, Greece
| | - George Trakakis
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas (FORTH/ICE-HT), Stadiou Street, Platani, Patras, 26504, Greece
| | - Costas Galiotis
- Institute of Chemical Engineering Sciences, Foundation of Research and Technology-Hellas (FORTH/ICE-HT), Stadiou Street, Platani, Patras, 26504, Greece.
- Department of Chemical Engineering, University of Patras, Patras, 26504, Greece.
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Hasa B, Martino E, Vakros J, Trakakis G, Galiotis C, Katsaounis A. Effect of Carbon Support on the Electrocatalytic Properties of Pt−Ru Catalysts. ChemElectroChem 2019. [DOI: 10.1002/celc.201901387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Bjorn Hasa
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece, E-mail
| | - Eftychia Martino
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece, E-mail
| | - John Vakros
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece, E-mail
| | - George Trakakis
- Institute of Chemical Engineering SciencesFoundation of Research for Technology (FORTH/ ICE-HT), PO Box 1414 GR-26504 Patras Greece
| | - Costas Galiotis
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece, E-mail
- Institute of Chemical Engineering SciencesFoundation of Research for Technology (FORTH/ ICE-HT), PO Box 1414 GR-26504 Patras Greece
| | - Alexandros Katsaounis
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece, E-mail
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Hasa B, Martino E, Vakros J, Trakakis G, Galiotis C, Katsaounis A. Front Cover: Effect of Carbon Support on the Electrocatalytic Properties of Pt−Ru Catalysts (ChemElectroChem 19/2019). ChemElectroChem 2019. [DOI: 10.1002/celc.201901388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Bjorn Hasa
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
| | - Eftychia Martino
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
| | - John Vakros
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
| | - George Trakakis
- Institute of Chemical Engineering SciencesFoundation for Research and Technology (FORTH/ICE-HT) PO Box 1414 GR-26504 Patras Greece
| | - Costas Galiotis
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
- Institute of Chemical Engineering SciencesFoundation for Research and Technology (FORTH/ICE-HT) PO Box 1414 GR-26504 Patras Greece
| | - Alexandros Katsaounis
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
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Hasa B, Martino E, Vakros J, Trakakis G, Galiotis C, Katsaounis A. Effect of Carbon Support on the Electrocatalytic Properties of Pt−Ru Catalysts. ChemElectroChem 2019. [DOI: 10.1002/celc.201900566] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Bjorn Hasa
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
| | - Eftychia Martino
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
| | - John Vakros
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
| | - George Trakakis
- Institute of Chemical Engineering SciencesFoundation for Research and Technology (FORTH/ICE-HT) PO Box 1414 GR-26504 Patras Greece
| | - Costas Galiotis
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
- Institute of Chemical Engineering SciencesFoundation for Research and Technology (FORTH/ICE-HT) PO Box 1414 GR-26504 Patras Greece
| | - Alexandros Katsaounis
- Department of Chemical EngineeringUniversity of Patras Caratheodory 1 St GR-26504 Patras Greece
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Bekris L, Frontistis Z, Trakakis G, Sygellou L, Galiotis C, Mantzavinos D. Graphene: A new activator of sodium persulfate for the advanced oxidation of parabens in water. Water Res 2017; 126:111-121. [PMID: 28934645 DOI: 10.1016/j.watres.2017.09.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/19/2017] [Accepted: 09/09/2017] [Indexed: 05/27/2023]
Abstract
Graphene was successfully employed as a catalyst for the activation of sodium persulfate, towards the effective degradation of propylparaben, an emerging micro-pollutant, representative of the parabens family. A novel process is proposed which utilizes a commercial graphene nano-powder as the catalyst and sodium persulfate as the oxidizing agent. It was found that over 95% of micro-pollutant degradation occurs within 15 min of reaction time. The effects of catalyst loading (75 mg/L to 1 g/L), sodium persulfate (SPS) concentration (10 mg/L to 1 g/L), initial solution pH (3-9) and initial paraben concentration (0.5 mg/L to 5 mg/L) were examined. Experiments were carried out in different aqueous conditions, including ultrapure water, bottled water and wastewater in order to investigate their effect on the degradation rate. The efficiency of the process was lower at complex water matrices signifying the role of organic matter as scavenger of the oxidant species. The role of radical scavengers was also investigated through the addition of methanol and tert-butanol in several concentrations, which was found to be important only in relatively high values. An experiment in which propylparaben was substituted by methylparaben was conducted and similar results were obtained. The consumption of SPS was found to be high in all pH conditions tested, surpassing 80% in near neutral environment. However, the results indicate that the sulfate radicals formed react with water in alkaline conditions, which are the optimal for the reaction, producing hydroxyl radicals which appear to be the dominant species leading to the rapid degradation of propylparaben. To the best of our knowledge, this is the first time pristine graphene has been implemented as an activator of sodium persulfate for the effective oxidation of micro-pollutants.
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Affiliation(s)
- Leonidas Bekris
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece
| | - Zacharias Frontistis
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece.
| | - George Trakakis
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology, PO Box 1414, GR-26504 Patras, Greece
| | - Lamprini Sygellou
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology, PO Box 1414, GR-26504 Patras, Greece
| | - Costas Galiotis
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; Institute of Chemical Engineering Sciences, Foundation for Research and Technology, PO Box 1414, GR-26504 Patras, Greece
| | - Dionissios Mantzavinos
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece
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Trakakis G, Tasis D, Parthenios J, Galiotis C, Papagelis K. Structural Properties of Chemically Functionalized Carbon Nanotube Thin Films. Materials (Basel) 2013; 6:2360-2371. [PMID: 28809277 PMCID: PMC5458945 DOI: 10.3390/ma6062360] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/03/2013] [Accepted: 06/05/2013] [Indexed: 11/22/2022]
Abstract
Buckypapers are thin sheets of randomly entangled carbon nanotubes, which are highly porous networks. They are strong candidates for a number of applications, such as reinforcing materials for composites. In this work, buckypapers were produced from multiwall carbon nanotubes, pre-treated by two different chemical processes, either an oxidation or an epoxidation reaction. Properties, such as porosity, the mechanical and electrical response are investigated. It was found that the chemical pretreatment of carbon nanotubes strongly affects the structural properties of the buckypapers and, consecutively, their mechanical and electrical performance.
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Affiliation(s)
- George Trakakis
- Institute of Chemical Engineering and High Temperature Processes, Foundation of Research and Technology Hellas, P.O. Box 1414, Patras GR-26504, Greece.
| | - Dimitrios Tasis
- Institute of Chemical Engineering and High Temperature Processes, Foundation of Research and Technology Hellas, P.O. Box 1414, Patras GR-26504, Greece.
| | - John Parthenios
- Institute of Chemical Engineering and High Temperature Processes, Foundation of Research and Technology Hellas, P.O. Box 1414, Patras GR-26504, Greece.
| | - Costas Galiotis
- Institute of Chemical Engineering and High Temperature Processes, Foundation of Research and Technology Hellas, P.O. Box 1414, Patras GR-26504, Greece.
- Department of Materials Science, University of Patras, Patras GR-26504, Greece.
| | - Konstantinos Papagelis
- Institute of Chemical Engineering and High Temperature Processes, Foundation of Research and Technology Hellas, P.O. Box 1414, Patras GR-26504, Greece.
- Department of Materials Science, University of Patras, Patras GR-26504, Greece.
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