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Ruta V, Di Liberto G, Moriggi F, Ivanov YP, Divitini G, Bussetti G, Barbera V, Bajada MA, Galimberti M, Pacchioni G, Vilé G. Copper Single Atoms Chelated on Ligand-Modified Carbon for Ullmann-type C-O Coupling. ChemSusChem 2024; 17:e202301529. [PMID: 38050778 DOI: 10.1002/cssc.202301529] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/06/2023]
Abstract
Cross-coupling reactions are of great importance in chemistry due to their ability to facilitate the construction of complex organic molecules. Among these reactions, the Ullmann-type C-O coupling between phenols and aryl halides is particularly noteworthy and useful for preparing diarylethers. However, this reaction typically relies on homogeneous catalysts that rapidly deactivate under harsh reaction conditions. In this study, we introduce a novel heterogeneous catalyst for the Ullmann-type C-O coupling reaction, comprised of isolated Cu atoms chelated to a tetraethylenepentamine-pyrrole ligand that is immobilized on graphite nanoplatelets. The catalytic study reveals the recyclability of the material, and demonstrates the crucial role of the pyrrole linker in stabilizing the Cu sites. The work expands the potential of single-atom catalyst nanoarchitectures and underscores the significance of ligands in stabilizing metals in cationic forms, providing a novel, tailored catalyst for cross-coupling chemistries.
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Affiliation(s)
- Vincenzo Ruta
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Giovanni Di Liberto
- Department of Materials Science, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, IT-20125, Milano, Italy
| | - Francesco Moriggi
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Yurii P Ivanov
- Electron Spectroscopy and Nanoscopy, Italian Institute of Technology, Via Morego 30, IT-16163, Genova, Italy
| | - Giorgio Divitini
- Electron Spectroscopy and Nanoscopy, Italian Institute of Technology, Via Morego 30, IT-16163, Genova, Italy
| | - Gianlorenzo Bussetti
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Vincenzina Barbera
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Mark A Bajada
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Maurizio Galimberti
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
| | - Gianfranco Pacchioni
- Department of Materials Science, Università degli Studi di Milano-Bicocca, Via Roberto Cozzi 55, IT-20125, Milano, Italy
| | - Gianvito Vilé
- Department of Chemistry, Materials, and Chemical Engineering, "Giulio Natta" Politecnico di Milano, Piazza Leonardo da Vinci 32, IT-20133, Milano, Italy
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Kanhere SV, Güzdemir Ö, Ogale AA. Micro-Finned Nanocomposite Films for Enhanced Transport Properties: Graphite Nanoplatelet-Filled Linear Low-Density Polyethylene. Polymers (Basel) 2023; 15:4411. [PMID: 38006136 PMCID: PMC10675350 DOI: 10.3390/polym15224411] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/03/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Metals are being replaced with high-performance and lightweight polymers, but their low thermal conductivity and poor electrostatic dissipative properties are significant problems. For the protection of sensitive electronic circuitry in automotive and aerospace parts, some device housing materials must provide electrostatic discharge and dissipate heat generated at higher rates as electronic circuits are increasingly miniaturized. Micro-texturing on the film surface can greatly enhance the heat dissipation area and was investigated in this study using low-cost graphite nanoplatelet (GNP)-filled LLDPE films. Micro-finned films (30 vol% GNP) having a 51 ± 10% larger heat-dissipation area were successfully produced using a continuous extrusion process. The through-thickness thermal conductivity of 30 vol% GNP-filled LLDPE was measured at 1.3 W/m·K, which represents a 200% improvement over that of pure LLDPE. For a GNP content of 30 vol%, the surface and volume electrical conductivity of the composite films also increased by 8 orders of magnitude (resistivity down from ≈1015 to 107 Ω·cm) and electrostatic decay time reduced to a below-resolution limit of 0.01 s, at par with military standard requirements. Thus, micro-fin textured GNP-LLDPE offers a unique combination of electrical and thermal transport desired for the protection of electronic encapsulation materials.
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Affiliation(s)
| | | | - Amod A. Ogale
- Center for Advanced Engineering Films and Fibers (CAEFF), Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, SC 29634, USA; (S.V.K.)
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Herreros-Lucas C, Vila-Fungueiriño JM, Giménez-López MDC. Electrochemically Versatile Graphite Nanoplatelets Prepared by a Straightforward, Highly Efficient, and Scalable Route. ACS Appl Mater Interfaces 2023; 15:21375-21383. [PMID: 37015345 PMCID: PMC10165606 DOI: 10.1021/acsami.2c22495] [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] [Indexed: 05/05/2023]
Abstract
Nanostructured carbon materials with tailor-made structures (e.g., morphology, topological defect, dopant, and surface area) are of significant interest for a variety of applications. However, the preparation method selected for obtaining these tailor-made structures determines the area of application, precluding their use in other technological areas of interest. Currently, there is a lack of simple and low-cost methodologies versatile enough for obtaining freestanding carbon nanostructures that can be used in either energy storage or chemical detection. Here, a novel methodology for the development of a versatile electrochemically active platform based on freestanding graphite nanoplatelets (GNP) has been developed by exploiting the interiors of hollow carbon nanofibers (CNF) comprising nanographene stacks using dry ball-milling. Even though ball-milling could be considered as a universal method for any carbonaceous material, often, it is not as simple (one step, no purification, and no solvents), efficient (just GNP without tubular structures), and quick (just 20 min) as the sustainable method developed in this work, free of surfactants and stabilizer agents. We demonstrate that the freestanding GNP developed in this work (with an average thickness of 3.2 nm), due to the selective edge functionalization with the minimal disruption of the basal plane, can act either as a supercapacitor or as a chemical sensor, showing both a dramatic improvement in the charge storage ability of more than 30 times and an enhanced detection of electrochemically active molecules such as ascorbic acid with a 236 mV potential shift with respect to CNF in both cases. As shown here, GNP stand as an excellent versatile alternative compared to the standard commercially available carbon-based materials. Overall, our approach paves the way for the discovery of new nanocarbon-based electrochemical active platforms with a wide electrochemical applicability.
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Affiliation(s)
- Carlos Herreros-Lucas
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - José Manuel Vila-Fungueiriño
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - María Del Carmen Giménez-López
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, U.K
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4
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Agustina E, Goak JC, Lee S, Kim Y, Hong SC, Seo Y, Lee N. Effect of Graphite Nanoplatelet Size and Dispersion on the Thermal and Mechanical Properties of Epoxy-Based Nanocomposites. Nanomaterials (Basel) 2023; 13:nano13081328. [PMID: 37110912 PMCID: PMC10144909 DOI: 10.3390/nano13081328] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/03/2023] [Accepted: 04/08/2023] [Indexed: 06/12/2023]
Abstract
This study investigated the effect of graphite nanoplatelet (GNP) size and dispersion on the thermal conductivities and tensile strengths of epoxy-based composites. GNPs of four different platelet sizes, ranging from 1.6 to 3 µm, were derived by mechanically exfoliating and breaking expanded graphite (EG) particles using high-energy bead milling and sonication. The GNPs were used as fillers at loadings of 0-10 wt%. As the GNP size and loading amount increased, the thermal conductivities of the GNP/epoxy composites increased, but their tensile strengths decreased. However, interestingly, the tensile strength reached a maximum value at the low GNP content of 0.3% and thereafter decreased, irrespective of the GNP size. Our observations of the morphologies and dispersions of the GNPs in the composites indicated that the thermal conductivity was more likely related to the size and loading number of fillers, whereas the tensile strength was more influenced by the dispersion of fillers in the matrix.
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Kumar V, Alam MN, Park SS. Soft Composites Filled with Iron Oxide and Graphite Nanoplatelets under Static and Cyclic Strain for Different Industrial Applications. Polymers (Basel) 2022; 14:2393. [PMID: 35745969 DOI: 10.3390/polym14122393] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/03/2022] [Accepted: 06/10/2022] [Indexed: 12/04/2022] Open
Abstract
Simultaneously exhibiting both a magnetic response and piezoelectric energy harvesting in magneto-rheological elastomers (MREs) is a win-win situation in a soft (hardness below 65) composite-based device. In the present work, composites based on iron oxide (Fe2O3) were prepared and exhibited a magnetic response; other composites based on the electrically conductive reinforcing nanofiller, graphite nanoplatelets (GNP), were also prepared and exhibited energy generation. A piezoelectric energy-harvesting device based on composites exhibited an impressive voltage of ~10 V and demonstrated a high durability of 0.5 million cycles. These nanofillers were added in room temperature vulcanized silicone rubber (RTV-SR) and their magnetic response and piezoelectric energy generation were studied both in single and hybrid form. The hybrid composite consisted of 10 per hundred parts of rubber (phr) of Fe2O3 and 10 phr of GNP. The experimental data show that the compressive modulus of the composites was 1.71 MPa (virgin), 2.73 (GNP), 2.65 MPa (Fe2O3), and 3.54 MPa (hybrid). Similarly, the fracture strain of the composites was 89% (virgin), 109% (GNP), 105% (Fe2O3), 133% (hybrid). Moreover, cyclic multi-hysteresis tests show that the hybrid composites exhibiting higher mechanical properties had the shortcoming of showing higher dissipation losses. In the end, this work demonstrates a rubber composite that provides an energy-harvesting device with an impressive voltage, high durability, and MREs with high magnetic sensitivity.
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Omrani E, Moghadam AD, Kasar AK, Rohatgi P, Menezes PL. Tribological Performance of Graphite Nanoplatelets Reinforced Al and Al/Al 2O 3 Self-Lubricating Composites. Materials (Basel) 2021; 14:ma14051183. [PMID: 33802337 PMCID: PMC7959118 DOI: 10.3390/ma14051183] [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: 12/08/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 11/16/2022]
Abstract
In the present work, the effect of graphite nanoplatelets (GNPs) on tribological properties of the aluminum (Al), and Al/alumina (Al2O3) composite are studied. GNPs are multilayer graphene sheets which were used as a solid lubricant material. Two sets of composites, Al/GNPs and Al/GNPs/Al2O3 with varying amounts of reinforcements, were synthesized by powder metallurgy that involves cold compaction followed by hot compaction. The hardness of the composites increased with the addition of GNPs and Al2O3. The Al/GNPs composite with 1 wt.% of GNPs (Al/1GNPs) showed a 20% increase in hardness whereas Al/GNPs/ Al2O3 composite with 1 wt.% GNPs and 2 wt.% Al2O3 (Al/1GNPs/2Al2O3) showed 27% increases in hardness compared to the pure Al. The coefficient of friction measured at 20 N was observed to be 22% and 53% lesser for Al/1GNPs and Al/1GNPs/2Al2O3, respectively, compared to corresponding alloys without graphene Al. The X-ray diffraction and scanning electron microscopy analysis revealed the presence of GNPs at the worn surface after the tribology tests. The wear rate was also reduced significantly. In comparison with pure Al, the Al/1GNPs and Al/1GNPs/2Al2O3 composites resulted in 5- and 20-times lesser wear rate, respectively. The addition of Al2O3 caused reduction in wear rate due to higher hardness and load carrying ability, whereas composites with more than 1 wt.% GNPs showed higher wear rate due to lower hardness and higher porosity. The Al/1GNPs/2Al2O3 composite exhibited the least coefficient of friction (0.2–0.25) and wear rate (1 × 10−6–4 × 10−6 mm3/N.m) compared to other GNPs and Al2O3 reinforced Al composites. The worn surfaces were further analyzed to understand the wear mechanism by Raman spectroscopy, transmission electron microscopy, and x-ray diffraction to detect the Al4C3 phase formation, chemical bonding, and defect formation in graphene.
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Affiliation(s)
- Emad Omrani
- Department of Materials Science and Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA; (E.O.); (A.D.M.)
- Department of Mechanical Engineering, University of Nevada, Reno, NV 89557, USA;
| | - Afsaneh Dorri Moghadam
- Department of Materials Science and Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA; (E.O.); (A.D.M.)
| | - Ashish K. Kasar
- Department of Mechanical Engineering, University of Nevada, Reno, NV 89557, USA;
| | - Pradeep Rohatgi
- Department of Materials Science and Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA; (E.O.); (A.D.M.)
- Correspondence: (P.R.); (P.L.M.)
| | - Pradeep L. Menezes
- Department of Materials Science and Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA; (E.O.); (A.D.M.)
- Correspondence: (P.R.); (P.L.M.)
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7
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Pandit S, Gaska K, Mokkapati VRSS, Celauro E, Derouiche A, Forsberg S, Svensson M, Kádár R, Mijakovic I. Precontrolled Alignment of Graphite Nanoplatelets in Polymeric Composites Prevents Bacterial Attachment. Small 2020; 16:e1904756. [PMID: 31916683 DOI: 10.1002/smll.201904756] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [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: 08/23/2019] [Revised: 12/08/2019] [Indexed: 06/10/2023]
Abstract
Graphene coatings composed of vertical spikes are shown to mitigate bacterial attachment. Such coatings present hydrophobic edges of graphene, which penetrate the lipid bilayers causing physical disruption of bacterial cells. However, manufacturing of such surfaces on a scale required for antibacterial applications is currently not feasible. This study explores whether graphite can be used as a cheaper alternative to graphene coatings. To examine this, composites of graphite nanoplatelets (GNP) and low-density polyethylene (LDPE) are extruded in controlled conditions to obtain controlled orientation of GNP flakes within the polymer matrix. Flakes are exposed by etching the surface of GNP-LDPE nanocomposites and antibacterial activity is evaluated. GNP nanoflakes on the extruded samples interact with bacterial cell membranes, physically damaging the cells. Bactericidal activity is observed dependent on orientation and nanoflakes density. Composites with high density of GNP (≥15%) present two key advantages: i) they decrease bacterial viability by a factor of 99.9999%, which is 10 000-fold improvement on the current benchmark, and ii) prevent bacterial colonization, thus drastically reducing the numbers of dead cells on the surface. The latter is a key advantage for longer-term biomedical applications, since these surfaces will not have to be cleaned or replaced for longer periods.
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Affiliation(s)
- Santosh Pandit
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Göteborg, Sweden
| | - Karolina Gaska
- Industrial and Materials Science, Chalmers University of Technology, SE 412 96, Göteborg, Sweden
| | - Venkata R S S Mokkapati
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Göteborg, Sweden
| | - Emanuele Celauro
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Göteborg, Sweden
| | - Abderahmane Derouiche
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Göteborg, Sweden
| | | | - Magnus Svensson
- Wellspect HealthCare, Aminogatan 1, SE 431 21, Mölndal, Sweden
| | - Roland Kádár
- Industrial and Materials Science, Chalmers University of Technology, SE 412 96, Göteborg, Sweden
| | - Ivan Mijakovic
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Göteborg, Sweden
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Eleuteri M, Bernal M, Milanesio M, Monticelli O, Fina A. Stereocomplexation of Poly(Lactic Acid)s on Graphite Nanoplatelets: From Functionalized Nanoparticles to Self-assembled Nanostructures. Front Chem 2019; 7:176. [PMID: 30984744 PMCID: PMC6450084 DOI: 10.3389/fchem.2019.00176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 01/31/2019] [Accepted: 03/06/2019] [Indexed: 11/13/2022] Open
Abstract
The control of nanostructuration of graphene and graphene related materials (GRM) into self-assembled structures is strictly related to the nanoflakes chemical functionalization, which may be obtained via covalent grafting of non-covalent interactions, mostly exploiting π-stacking. As the non-covalent functionalization does not affect the sp2 carbon structure, this is often exploited to preserve the thermal and electrical properties of the GRM and it is a well-known route to tailor the interaction between GRM and organic media. In this work, non-covalent functionalization of graphite nanoplatelets (GnP) was carried out with ad-hoc synthesized pyrene-terminated oligomers of polylactic acid (PLA), aiming at the modification of GnP nanopapers thermal properties. PLA was selected based on the possibility to self-assemble in crystalline domains via stereocomplexation of complementary poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) enantiomers. Pyrene-initiated PLLA and PDLA were indeed demonstrated to anchor to the GnP surface. Calorimetric and X-ray diffraction investigations highlighted the enantiomeric PLAs adsorbed on the surface of the nanoplatelets self-organize to produce highly crystalline stereocomplex domains. Most importantly, PLLA/PDLA stereocomplexation delivered a significantly higher efficiency in nanopapers heat transfer, in particular through the thickness of the nanopaper. This is explained by a thermal bridging effect of crystalline domains between overlapped GnP, promoting heat transfer across the nanoparticles contacts. This work demonstrates the possibility to enhance the physical properties of contacts within a percolating network of GRM via the self-assembly of macromolecules and opens a new way for the engineering of GRM-based nanostructures.
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Affiliation(s)
- Matteo Eleuteri
- Dipartimento di Scienza Applicata e Tecnologia, Sede di Alessandria, Politecnico di Torino, Alessandria, Italy
| | - Mar Bernal
- Dipartimento di Scienza Applicata e Tecnologia, Sede di Alessandria, Politecnico di Torino, Alessandria, Italy
| | - Marco Milanesio
- Dipartimento di Scienze e Innovazione Tecnologica, Università degli Studi del Piemonte Orientale, Alessandria, Italy
| | - Orietta Monticelli
- Dipartimento di Chimica e Chimica Industriale, Università di Genova, Genova, Italy
| | - Alberto Fina
- Dipartimento di Scienza Applicata e Tecnologia, Sede di Alessandria, Politecnico di Torino, Alessandria, Italy
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Hernandez-Aldave S, Tarat A, McGettrick JD, Bertoncello P. Voltammetric Detection of Caffeine in Beverages at Nafion/ Graphite Nanoplatelets Layer-by-Layer Films. Nanomaterials (Basel) 2019; 9:E221. [PMID: 30736450 PMCID: PMC6410159 DOI: 10.3390/nano9020221] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 12/29/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 12/19/2022]
Abstract
We report for the first time a procedure in which Nafion/Graphite nanoplatelets (GNPs) thin films are fabricated using a modified layer-by-layer (LbL) method. The method consists of dipping a substrate (quartz and/or glassy carbon electrodes) into a composite solution made of Nafion and GNPs dissolved together in ethanol, followed by washing steps in water. This procedure allowed the fabrication of multilayer films of (Nafion/GNPs)n by means of hydrogen bonding and hydrophobic‒hydrophobic interactions between Nafion, GNPs, and the corresponding solid substrate. The average thickness of each layer evaluated using profilometer corresponds to ca. 50 nm. The as-prepared Nafion/GNPs LbL films were characterized using various spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), FTIR, and optical microscopy. This characterization highlights the presence of oxygen functionalities that support a mechanism of self-assembly via hydrogen bonding interactions, along with hydrophobic interactions between the carbon groups of GNPs and the Teflon-like (carbon‒fluorine backbone) of Nafion. We showed that Nafion/GNPs LbL films can be deposited onto glassy carbon electrodes and utilized for the voltammetric detection of caffeine in beverages. The results showed that Nafion/GNPs LbL films can achieve a limit of detection for caffeine (LoD) of 0.032 μM and linear range between 20‒250 μM using differential pulse voltammetry, whereas, using cyclic voltammetry LoD and linear range were found to be 24 μM and 50‒5000 μM, respectively. Voltammetric detection of caffeine in beverages showed good agreement between the values found experimentally and those reported by the beverage producers. The values found are also in agreement with those obtained using a standard spectrophotometric method. The proposed method is appealing because it allows the fabrication of Nafion/GNPs thin films in a simple fashion using a single-step procedure, rather than using composite solutions with opposite electrostatic charge, and also allows the detection of caffeine in beverages without any pre-treatment or dilution of the real samples. The proposed method is characterized by a fast response time without apparent interference, and the results were competitive with those obtained with other materials reported in the literature.
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Affiliation(s)
- Sandra Hernandez-Aldave
- Systems and Process Engineering Centre, College of Engineering, Swansea University, Bay Campus, Crwmlyn Burrows, Swansea SA1 8EN, UK.
| | - Afshin Tarat
- Perpetuus Advanced Materials, Unit B1, Olympus Court, Millstream Way, Swansea Vale, Llansamlet, SA7 0AQ, UK.
| | - James D McGettrick
- SPECIFIC, College of Engineering, Swansea University, Bay Campus, Swansea SA1 8EN, UK.
| | - Paolo Bertoncello
- Systems and Process Engineering Centre, College of Engineering, Swansea University, Bay Campus, Crwmlyn Burrows, Swansea SA1 8EN, UK.
- Centre for NanoHealth, Swansea University, Singleton Campus, Swansea SA2 8PP, UK.
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Fina A, Colonna S, Maddalena L, Tortello M, Monticelli O. Facile and Low Environmental Impact Approach to Prepare Thermally Conductive Nanocomposites Based on Polylactide and Graphite Nanoplatelets. ACS Sustain Chem Eng 2018; 6:14340-14347. [PMID: 30416891 PMCID: PMC6224122 DOI: 10.1021/acssuschemeng.8b03013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/06/2018] [Indexed: 06/09/2023]
Abstract
In this work, the preparation of nanocomposites based on poly(l-lactide) PLLA and graphite nanoplatelets (GNP) was assessed by applying, for the first time, the reactive extrusion (REX) polymerization approach, which is considered a low environmental impact method to prepare polymer systems and which allows an easy scalability. In particular, ad hoc synthesized molecules, constituted by a pyrene end group and a poly(d-lactide) (PDLA) chain (Pyr-d), capable of interacting with the surface of GNP layers as well as forming stereoblocks during the ring-opening polymerization (ROP) of l-lactide, were used. The nanocomposites were synthesized by adding to l-lactide the GNP/initiator system, prepared by dispersing the graphite in the acetone/Pyr-d solution, which was dried after the sonication process. DSC and X-ray diffraction measurements evidenced the stereocomplexation of the systems synthesized by using the pyrene-based initiators, whose extent turned out to depend on the PDLA chain length. All the prepared nanocomposites, including those synthesized starting from a classical initiator, that is, 1-dodecanol, retained similar electrical conductivity, whereas the thermal conductivity was found to increase in the stereocomplexed samples. Preferential localization of stereocomplexed PLA close to the interface with GNP was demonstrated by scanning probe microscopy (SPM) techniques, supporting an important role of local crystallinity in the thermal conductivity of the nanocomposites.
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Affiliation(s)
- Alberto Fina
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino-sede di Alessandria, viale Teresa Michel 5, 15121 Alessandria, Italy
| | - Samuele Colonna
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino-sede di Alessandria, viale Teresa Michel 5, 15121 Alessandria, Italy
| | - Lorenza Maddalena
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino-sede di Alessandria, viale Teresa Michel 5, 15121 Alessandria, Italy
| | - Mauro Tortello
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino-sede di Alessandria, viale Teresa Michel 5, 15121 Alessandria, Italy
| | - Orietta Monticelli
- Dipartimento
di Chimica e Chimica Industriale, Università
di Genova, Via Dodecaneso
31, 16146 Genova, Italy
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11
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Gonçalves J, Lima P, Krause B, Pötschke P, Lafont U, Gomes JR, Abreu CS, Paiva MC, Covas JA. Electrically Conductive Polyetheretherketone Nanocomposite Filaments: From Production to Fused Deposition Modeling. Polymers (Basel) 2018; 10:E925. [PMID: 30960850 DOI: 10.3390/polym10080925] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/26/2018] [Accepted: 08/15/2018] [Indexed: 11/17/2022] Open
Abstract
The present work reports the production and characterization of polyetheretherketone (PEEK) nanocomposite filaments incorporating carbon nanotubes (CNT) and graphite nanoplates (GnP), electrically conductive and suitable for fused deposition modeling (FDM) processing. The nanocomposites were manufactured by melt mixing and those presenting electrical conductivity near 10 S/m were selected for the production of filaments for FDM. The extruded filaments were characterized for mechanical and thermal conductivity, polymer crystallinity, thermal relaxation, nanoparticle dispersion, thermoelectric effect, and coefficient of friction. They presented electrical conductivity in the range of 1.5 to 13.1 S/m, as well as good mechanical performance and higher thermal conductivity compared to PEEK. The addition of GnP improved the composites’ melt processability, maintained the electrical conductivity at target level, and reduced the coefficient of friction by up to 60%. Finally, three-dimensional (3D) printed test specimens were produced, showing a Young’s modulus and ultimate tensile strength comparable to those of the filaments, but a lower strain at break and electrical conductivity. This was attributed to the presence of large voids in the part, revealing the need for 3D printing parameter optimization. Finally, filament production was up-scaled to kilogram scale maintaining the properties of the research-scale filaments.
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Simoncini A, Tagliaferri V, Ucciardello N. High Thermal Conductivity of Copper Matrix Composite Coatings with Highly-Aligned Graphite Nanoplatelets. Materials (Basel) 2017; 10:ma10111226. [PMID: 29068424 PMCID: PMC5706173 DOI: 10.3390/ma10111226] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [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: 09/07/2017] [Revised: 10/18/2017] [Accepted: 10/23/2017] [Indexed: 11/29/2022]
Abstract
Nanocomposite coatings with highly-aligned graphite nanoplatelets in a copper matrix were successfully fabricated by electrodeposition. For the first time, the disposition and thermal conductivity of the nanofiller has been evaluated. The degree of alignment and inclination of the filling materials has been quantitatively evaluated by polarized micro-Raman spectroscopy. The room temperature values of the thermal conductivity were extracted for the graphite nanoplatelets by the dependence of the Raman G-peak frequency on the laser power excitation. Temperature dependency of the G-peak shift has been also measured. Most remarkable is the global thermal conductivity of 640 ± 20 W·m−1·K−1 (+57% of copper) obtained for the composite coating by the flash method. Our experimental results are accounted for by an effective medium approximation (EMA) model that considers the influence of filler geometry, orientation, and thermal conductivity inside a copper matrix.
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Affiliation(s)
- Alessandro Simoncini
- Department of Enterprise Engineering "Mario Lucertini", University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy.
| | - Vincenzo Tagliaferri
- Department of Enterprise Engineering "Mario Lucertini", University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy.
| | - Nadia Ucciardello
- Department of Enterprise Engineering "Mario Lucertini", University of Rome "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy.
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Kádár R, Abbasi M, Figuli R, Rigdahl M, Wilhelm M. Linear and Nonlinear Rheology Combined with Dielectric Spectroscopy of Hybrid Polymer Nanocomposites for Semiconductive Applications. Nanomaterials (Basel) 2017; 7:E23. [PMID: 28336857 DOI: 10.3390/nano7020023] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/16/2017] [Accepted: 01/17/2017] [Indexed: 11/17/2022]
Abstract
The linear and nonlinear oscillatory shear, extensional and combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. The main focus was the influence of processing conditions on percolated poly(ethylene-butyl acrylate) (EBA) nanocomposite hybrids containing graphite nanoplatelets (GnP) and carbon black (CB). The rheological response of the samples was interpreted in terms of dispersion properties, filler distortion from processing, filler percolation, as well as the filler orientation and distribution dynamics inside the matrix. Evidence of the influence of dispersion properties was found in linear viscoelastic dynamic frequency sweeps, while the percolation of the nanocomposites was detected in nonlinearities developed in dynamic strain sweeps. Using extensional rheology, hybrid samples with better dispersion properties lead to a more pronounced strain hardening behavior, while samples with a higher volume percentage of fillers caused a drastic reduction in strain hardening. The rheo-dielectric time-dependent response showed that in the case of nanocomposites containing only GnP, the orientation dynamics leads to non-conductive samples. However, in the case of hybrids, the orientation of the GnP could be offset by the dispersing of the CB to bridge the nanoplatelets. The results were interpreted in the framework of a dual PE-BA model, where the fillers would be concentrated mainly in the BA regions. Furthermore, better dispersed hybrids obtained using mixing screws at the expense of filler distortion via extrusion processing history were emphasized through the rheo-dielectric tests.
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Mishra AK, Huang L. TiO2-decorated graphite nanoplatelet nanocomposites for high-temperature sensor applications. Small 2015; 11:361-366. [PMID: 25168184 DOI: 10.1002/smll.201401418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/05/2014] [Indexed: 06/03/2023]
Abstract
Temperature and/or composition mapping inside high temperature energy conversion and storage devices are challenging, yet of critical importance to improve the material design for optimum performance. Here, the great potential of TiO2 nanoparticle (NP)-decorated graphite nanoplatelet (GNP) nanocomposites as high temperature thermal senors or gas sensors is reported. Effects of the GNP substrate on phonon confinement in Raman spectrum, grain growth, and phase stability of anatase TiO2 NPs at high temperatures are systematically studied. Thermally sensitive Raman signatures, indicating the ultrafast grain growth of TiO2 NPs in response to short thermal shock treatments (0.1-25 s) at high temperatures, are exploited for high temperature thermal sensing applications. A very high accuracy of nearly 98% in temperature measurements is demonstrated for a given short-time thermal exposure. Thermal stability of anatase TiO2 NPs against transformation into the rutile phase in TiO2 -GNP nancomposites is substantially increased by controlling the surface area of the substrate, which would significantly improve the performance of TiO2 -based high temperature gas sensors.
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Affiliation(s)
- Ashish Kumar Mishra
- Department of Material Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
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Luo S, Liu T. SWCNT/graphite nanoplatelet hybrid thin films for self-temperature-compensated, highly sensitive, and extensible piezoresistive sensors. Adv Mater 2013; 25:5650-5657. [PMID: 23939948 DOI: 10.1002/adma.201301796] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/23/2013] [Indexed: 06/02/2023]
Abstract
Highly sensitive single-wall carbon nanotube/graphite nanoplatelet (SWCNT/GNP) hybrid thin-film sensors are developed, which possess the unique capability for self-temperature compensation. This unique property in combination with their high gauge sensitivity and large reversible extensibility promises the SWCNT/GNP hybrid thin film piezoresistive sensors for a wide range applications, such as in man-machine interaction and body monitoring.
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Affiliation(s)
- Sida Luo
- High-Performance Materials Institute, Florida State University, Tallahassee, Florida, 32310, USA
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Carotenuto G, Longo A, De Nicola S, Camerlingo C, Nicolais L. A simple mechanical technique to obtain carbon nanoscrolls from graphite nanoplatelets. Nanoscale Res Lett 2013; 8:403. [PMID: 24229076 PMCID: PMC3849441 DOI: 10.1186/1556-276x-8-403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/24/2013] [Indexed: 05/21/2023]
Abstract
A simple approach for the bulk production of carbon nanoscrolls (CNSs) is described. This method is based on the application of shear-friction forces to convert graphite nanoplatelets into carbon nanoscrolls using a bi-axially oriented polypropylene (BOPP) surface. The combined action of shear and friction forces causes the exfoliation of graphite nanoplatelets and the simultaneous roll-up of graphite layers. Evidence of the CNS formation is given by optical microscopy, scanning electron microscopy, and transmission electron microscopy. These investigations reveal that the CNSs have a long tube-like and fusiform structure with a hollow core surrounded by few layers of graphene. Micro-Raman spectroscopy shows that the produced structures are not defect free, and optical spectroscopy reveals distinctive features due to the presence of two weak absorption bands at 224 and 324 nm.
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Affiliation(s)
- Gianfranco Carotenuto
- Institute for Composite and Biomedical Materials, National Research Council, Viale Kennedy, 54 - Mostra d'Oltremare Pad. 20, Naples 80125, Italy
| | - Angela Longo
- Institute for Composite and Biomedical Materials, National Research Council, Viale Kennedy, 54 - Mostra d'Oltremare Pad. 20, Naples 80125, Italy
| | - Sergio De Nicola
- SPIN Institute, National Research Council, Complesso Universitario di M.S. Angelo, Via Cinthia, Naples 80126, Italy
- INFN Sezione di Napoli, Complesso Universitario di M.S. Angelo, Via Cinthia, Naples 80126, Italy
| | - Carlo Camerlingo
- Institute of Cybernetics “E. Caianiello”, National Research Council, Via Campi Flegrei 34, Pozzuoli 80078, Italy
| | - Luigi Nicolais
- Department of Material Engineering and Production, University of Naples “Federico II”, Piazzale Tecchio, 80, Naples 80125, Italy
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Ma-Hock L, Strauss V, Treumann S, Küttler K, Wohlleben W, Hofmann T, Gröters S, Wiench K, van Ravenzwaay B, Landsiedel R. Comparative inhalation toxicity of multi-wall carbon nanotubes, graphene, graphite nanoplatelets and low surface carbon black. Part Fibre Toxicol 2013; 10:23. [PMID: 23773277 PMCID: PMC3720229 DOI: 10.1186/1743-8977-10-23] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 05/10/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Carbon nanotubes, graphene, graphite nanoplatelets and carbon black are seemingly chemically identical carbon-based nano-materials with broad technological applications. Carbon nanotubes and carbon black possess different inhalation toxicities, whereas little is known about graphene and graphite nanoplatelets. METHODS In order to compare the inhalation toxicity of the mentioned carbon-based nanomaterials, male Wistar rats were exposed head-nose to atmospheres of the respective materials for 6 hours per day on 5 consecutive days. Target concentrations were 0.1, 0.5, or 2.5 mg/m3 for multi-wall carbon nanotubes and 0.5, 2.5, or 10 mg/m3 for graphene, graphite nanoplatelets and low-surface carbon black. Toxicity was determined after end of exposure and after three-week recovery using broncho-alveolar lavage fluid and microscopic examinations of the entire respiratory tract. RESULTS No adverse effects were observed after inhalation exposure to 10 mg/m3 graphite nanoplatelets or relatively low specific surface area carbon black. Increases of lavage markers indicative for inflammatory processes started at exposure concentration of 0.5 mg/m3 for multi-wall carbon nanotubes and 10 mg/m3 for graphene. Consistent with the changes in lavage fluid, microgranulomas were observed at 2.5 mg/m3 multi-wall carbon nanotubes and 10 mg/m3 graphene. In order to evaluate volumetric loading of the lung as the key parameter driving the toxicity, deposited particle volume was calculated, taking into account different methods to determine the agglomerate density. However, the calculated volumetric load did not correlate to the toxicity, nor did the particle surface burden of the lung. CONCLUSIONS The inhalation toxicity of the investigated carbon-based materials is likely to be a complex interaction of several parameters. Until the properties which govern the toxicity are identified, testing by short-term inhalation is the best option to identify hazardous properties in order to avoid unsafe applications or select safer alternatives for a given application.
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Affiliation(s)
- Lan Ma-Hock
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
| | - Volker Strauss
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
| | - Silke Treumann
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
| | - Karin Küttler
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
| | | | - Thomas Hofmann
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
| | - Sibylle Gröters
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
| | - Karin Wiench
- Product Safety, BASF SE, 67056 Ludwigshafen, Germany
| | | | - Robert Landsiedel
- Experimental Toxicology and Ecology, BASF SE, 67056 Ludwigshafen, Germany
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Carotenuto G, Romeo V, De Nicola S, Nicolais L. Graphite nanoplatelet chemical cross-linking by elemental sulfur. Nanoscale Res Lett 2013; 8:94. [PMID: 23425002 PMCID: PMC3605144 DOI: 10.1186/1556-276x-8-94] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 02/05/2013] [Indexed: 05/12/2023]
Abstract
Graphite nanoplatelets (GNPs) react with elemental sulfur to provide a mechanically stable, spongy material characterized by good electrical conductivity and high surface development; such unique property combination makes these novel nanostructured materials very useful for applications in different technological fields. The carbon-sulfur reaction can be accurately investigated by thermal analysis (differential scanning calorimetry and thermogravimetric analysis) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy. The thermal treatment required for the formation of electrically conductive monosulfur connections among the GNP unities has been investigated. PACS: 81.05.Ue, 81.05.Rm, 81.16.Be.
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Affiliation(s)
- Gianfranco Carotenuto
- Institute for Composite and Biomedical Materials, CNR. P.le Tecchio, 80, 80125, Naples, Italy
| | - Valentina Romeo
- Institute for Composite and Biomedical Materials, CNR. P.le Tecchio, 80, 80125, Naples, Italy
| | - Sergio De Nicola
- Istituto Nazionale di Ottica, CNR, Via Campi Flegrei, 34, Pozzuoli 80078, Italy
- INFN Sezione di Napoli, Complesso Universitario di M.S. Angelo, via Cinthia, Naples 80126, Italy
| | - Luigi Nicolais
- Department of Material Engineering and Production, University “Federico II” of Naples, P.le Tecchio, 80, Naples 80125, Italy
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