1
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Fu B, Tzitzios V, Zhang Q, Rodriguez B, Pissas M, Sofianos MV. Exploring the Magnetic and Electrocatalytic Properties of Amorphous MnB Nanoflakes. Nanomaterials (Basel) 2023; 13:300. [PMID: 36678053 PMCID: PMC9862160 DOI: 10.3390/nano13020300] [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: 12/21/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) metal borides are a class of ceramic materials with diverse structural and topological properties. These diverse material properties of metal borides are what forms the basis of their interdisciplinarity and their applicability in various research fields. In this study, we highlight which fundamental and practical parameters need to be taken into consideration when designing nanomaterials for specific applications. A simple one-pot chemical reduction method was applied for the synthesis of manganese mono-boride nanoflakes at room temperature. How the specific surface area and boron-content of the as-synthesized manganese mono-boride nanoflakes influence their magnetic and electrocatalytic properties is reported. The sample with the highest specific surface area and boron content demonstrated the best magnetic and electrocatalytic properties in the HER. Whereas the sample with the lowest specific surface area and boron content exhibited the best electric conductivity and electrocatalytic properties in the OER.
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Affiliation(s)
- Boxiao Fu
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Vasileios Tzitzios
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research “Demokritos”, 15310 Athens, Greece
| | - Qiancheng Zhang
- School of Physics, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Brian Rodriguez
- School of Physics, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael Pissas
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research “Demokritos”, 15310 Athens, Greece
| | - Maria Veronica Sofianos
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
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2
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Basina G, Diamantopoulos G, Devlin E, Psycharis V, Alhassan SM, Pissas M, Hadjipanayis G, Tomou A, Bouras A, Hadjipanayis C, Tzitzios V. LAPONITE® nanodisk-"decorated" Fe 3O 4 nanoparticles: a biocompatible nano-hybrid with ultrafast magnetic hyperthermia and MRI contrast agent ability. J Mater Chem B 2022; 10:4935-4943. [PMID: 35535802 DOI: 10.1039/d2tb00139j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Magnetic Fe3O4 nanoparticles "decorated" by LAPONITE® nanodisks have been materialized utilizing the Schikorr reaction following a facile approach and tested as mediators of heat for localized magnetic hyperthermia (MH) and as magnetic resonance imaging (MRI) agents. The synthetic protocol involves the interaction between two layered inorganic compounds, ferrous hydroxide, Fe(OH)2, and the synthetic smectite LAPONITE® clay Na0.7+[(Si8Mg5.5Li0.3)O20(OH)4]0.7-, towards the formation of superparamagnetic Fe3O4 nanoparticles, which are well decorated by the diamagnetic clay nanodisks. The latter imparts high negative ζ-potential values (up to -34.1 mV) to the particles, which provide stability against flocculation and precipitation, resulting in stable water dispersions. The obtained LAPONITE®-"decorated" Fe3O4 nanohybrids were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, dynamic light scattering (DLS) and vibrating sample magnetometry (VSM) at room temperature, revealing superior magnetic hyperthermia performance with specific absorption rate (SAR) values reaching 540 W gFe-1 (28 kA m-1, 150 kHz) for the hybrid material with a magnetic loading of 50 wt% Fe3O4/LAPONITE®. Toxicity studies were also performed with human glioblastoma (GBM) cells and human foreskin fibroblasts (HFF), which show negligible to no toxicity. Furthermore, T2-weighted MR imaging of rodent brain shows that the LAPONITE®-"decorated" Fe3O4 nanohybrids predominantly affected the transverse T2 relaxation time of tissue water, which resulted in a signal drop on the MRI T2-weighted imaging, allowing for imaging of the magnetic nanoparticles.
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Affiliation(s)
- Georgia Basina
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19711, USA. .,Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece.
| | - George Diamantopoulos
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece.
| | - Eamonn Devlin
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece.
| | - Vassilis Psycharis
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece.
| | - Saeed M Alhassan
- Department of Chemical Engineering, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Michael Pissas
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece.
| | - George Hadjipanayis
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19711, USA.
| | - Aphrodite Tomou
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece. .,Goodfellow Cambridge Ltd., Ermine Business Park, Huntingdon PE29 6WR, Cambridge, UK
| | - Alexandros Bouras
- Brain Tumor Nanotechnology Laboratory, Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Constantinos Hadjipanayis
- Brain Tumor Nanotechnology Laboratory, Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Vasileios Tzitzios
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310, Athens, Greece. .,Department of Chemical Engineering, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
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3
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Tzitzios V. Synthesis, Development and Characterization of Magnetic Nanomaterials. Nanomaterials (Basel) 2022; 12:nano12071036. [PMID: 35407154 PMCID: PMC9000313 DOI: 10.3390/nano12071036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022]
Abstract
Magnetic nanomaterials in both thin films and in the form of nanoparticles, with various structures and morphologies, are among the most extensively studied categories of materials [...].
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Affiliation(s)
- Vasileios Tzitzios
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research "Demokritos", 15310 Athens, Greece
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4
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Cordoyiannis G, Lavrič M, Tzitzios V, Trček M, Lelidis I, Nounesis G, Kralj S, Thoen J, Kutnjak Z. Experimental Advances in Nanoparticle-Driven Stabilization of Liquid-Crystalline Blue Phases and Twist-Grain Boundary Phases. Nanomaterials (Basel) 2021; 11:2968. [PMID: 34835732 PMCID: PMC8618027 DOI: 10.3390/nano11112968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 10/07/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 01/04/2023]
Abstract
Recent advances in experimental studies of nanoparticle-driven stabilization of chiral liquid-crystalline phases are highlighted. The stabilization is achieved via the nanoparticles' assembly in the defect lattices of the soft liquid-crystalline hosts. This is of significant importance for understanding the interactions of nanoparticles with topological defects and for envisioned technological applications. We demonstrate that blue phases are stabilized and twist-grain boundary phases are induced by dispersing surface-functionalized CdSSe quantum dots, spherical Au nanoparticles, as well as MoS2 nanoplatelets and reduced-graphene oxide nanosheets in chiral liquid crystals. Phase diagrams are shown based on calorimetric and optical measurements. Our findings related to the role of the nanoparticle core composition, size, shape, and surface coating on the stabilization effect are presented, followed by an overview of and comparison with other related studies in the literature. Moreover, the key points of the underlying mechanisms are summarized and prospects in the field are briefly discussed.
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Affiliation(s)
- George Cordoyiannis
- Condensed Matter Physics Department, Jožef Stefan Institute, 1000 Ljubljana, Slovenia; (M.L.); (M.T.); (Z.K.)
- Faculty of Mechanical Engineering, Czech Technical University in Prague, 16600 Prague 6, Czech Republic
| | - Marta Lavrič
- Condensed Matter Physics Department, Jožef Stefan Institute, 1000 Ljubljana, Slovenia; (M.L.); (M.T.); (Z.K.)
| | - Vasileios Tzitzios
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research “Demokritos”, Aghia Paraskevi, 15310 Athens, Greece;
| | - Maja Trček
- Condensed Matter Physics Department, Jožef Stefan Institute, 1000 Ljubljana, Slovenia; (M.L.); (M.T.); (Z.K.)
| | - Ioannis Lelidis
- Faculty of Physics, National and Kapodistrian University of Athens, Zografou, 15784 Athens, Greece;
| | - George Nounesis
- Institute of Nuclear and Radiological Sciences and Technology, National Centre for Scientific Research “Demokritos”, Aghia Paraskevi, 15310 Athens, Greece;
| | - Samo Kralj
- Faculty of Natural Sciences, University of Maribor, 2000 Maribor, Slovenia;
| | - Jan Thoen
- Department of Physics and Astronomy, KU Leuven, 3001 Leuven, Belgium;
| | - Zdravko Kutnjak
- Condensed Matter Physics Department, Jožef Stefan Institute, 1000 Ljubljana, Slovenia; (M.L.); (M.T.); (Z.K.)
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Basina G, Khurshid H, Tzitzios N, Hadjipanayis G, Tzitzios V. Facile Organometallic Synthesis of Fe-Based Nanomaterials by Hot Injection Reaction. Nanomaterials (Basel) 2021; 11:1141. [PMID: 33924901 PMCID: PMC8145410 DOI: 10.3390/nano11051141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 04/05/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/18/2022]
Abstract
Fe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer. The injection temperature plays a very crucial role and higher temperatures enhance the stability and the resistance against oxidation. For the case of injection at 315 °C, the nanoparticles had around a 10 nm mean diameter and revealed 132 emu/g. Remarkably, a stable dispersion was created due to the colloids' surface functionalization in a nonpolar solvent.
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Affiliation(s)
- Georgia Basina
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Athens, Greece; (G.B.); (N.T.)
- Department of Chemical Engineering, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
| | - Hafsa Khurshid
- Department of Applied Physics and Astronomy, University of Sharjah, Sharjah 27272, United Arab Emirates;
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19711, USA;
| | - Nikolaos Tzitzios
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Athens, Greece; (G.B.); (N.T.)
| | - George Hadjipanayis
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19711, USA;
| | - Vasileios Tzitzios
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Athens, Greece; (G.B.); (N.T.)
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6
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Tzitzios V, Pillai V, Gioti C, Katsiotis M, Karagiannis T, Gournis D, Karakassides MA, Alhassan S. Ultrafine Ni 2P Nanoparticle-Decorated r-GO: A Novel Liquid-Phase Approach and Dibenzothiophene Hydro-desulfurization. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c05544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vasileios Tzitzios
- Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Athens, Greece
- Department of Chemical Engineering, Khalifa University of Science and Technology, Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates
| | - Vishnu Pillai
- Department of Chemical Engineering, Khalifa University of Science and Technology, Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates
| | - Christina Gioti
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece
| | | | - Thomas Karagiannis
- Department of Chemical Engineering, Khalifa University of Science and Technology, Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates
| | - Dimitrios Gournis
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece
| | - Michael A. Karakassides
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece
| | - Saeed Alhassan
- Department of Chemical Engineering, Khalifa University of Science and Technology, Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates
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7
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Wadi VS, Jena KK, Halique K, Brigita Rožič, Cmok L, Tzitzios V, Alhassan SM. Scalable High Refractive Index polystyrene-sulfur nanocomposites via in situ inverse vulcanization. Sci Rep 2020; 10:14924. [PMID: 32913231 PMCID: PMC7483506 DOI: 10.1038/s41598-020-71227-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 08/03/2020] [Indexed: 11/09/2022] Open
Abstract
In this work, we demostrate the preparation of low cost High Refractive Index polystyrene-sulfur nanocomposites in one step by combining inverse vulcanization and melt extrusion method. Poly(sulfur-1,3-diisopropenylbenzene) (PS-SD) copolymer nanoparticles (5 to 10 wt%) were generated in the polystyrene matrix via in situ inverse vulcanization reaction during extrusion process. Formation of SD copolymer was confirmed by FTIR and Raman spectroscopy. SEM and TEM further confirms the presence of homogeneously dispersed SD nanoparticles in the size range of 5 nm. Thermal and mechanical properties of these nanocomposites are comparable with the pristine polystyrene. The transparent nanocomposites exhibits High Refractive Index n = 1.673 at 402.9 nm and Abbe'y number ~ 30 at 10 wt% of sulfur loading. The nanocomposites can be easily processed into mold, films and thin films by melt processing as well as solution casting techniques. Moreover, this one step preparation method is scalable and can be extend to the other polymers.
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Affiliation(s)
- Vijay S Wadi
- Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE.
| | - Kishore K Jena
- Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE
| | - Kevin Halique
- Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE
| | - Brigita Rožič
- Institut "Jožef Stefan", P.O. Box 3000, 1001, Ljubljana, Slovenia
| | - Luka Cmok
- Institut "Jožef Stefan", P.O. Box 3000, 1001, Ljubljana, Slovenia
| | - Vasileios Tzitzios
- NCSR "Demokritos" Institute of Nanoscience and Nanotechnology, 15310, Athens, Greece
| | - Saeed M Alhassan
- Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE.
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8
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Yildiz S, Cetinkaya M, Ozbek H, Tzitzios V, Nounesis G. High-resolution birefringence investigation on the effect of surface-functionalized CdSe nanoparticles on the phase transitions of a smectic — A liquid crystal. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Subrati A, Kim Y, Al Wahedi Y, Tzitzios V, Alhassan S, Kim HJ, Lee S, Sakellis E, Boukos N, Stephen S, Lee SM, Lee JB, Fardis M, Papavassiliou G. Monitoring the multiphasic evolution of bismuth telluride nanoplatelets. CrystEngComm 2020. [DOI: 10.1039/d0ce00719f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bismuth telluride hexagonal nanoplatelets originate from electronically distinct thicker Bi-rich triangular nanoplatelets while being centrally knitted by Te nanorods.
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10
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Abel FM, Pourmiri S, Basina G, Tzitzios V, Devlin E, Hadjipanayis GC. Iron carbide nanoplatelets: colloidal synthesis and characterization. Nanoscale Adv 2019; 1:4476-4480. [PMID: 36134414 PMCID: PMC9417806 DOI: 10.1039/c9na00526a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/06/2019] [Indexed: 05/18/2023]
Abstract
Iron carbide nanoplatelets with an orthorhombic Fe3C structure were synthesized following a simple liquid chemical approach. The formation of the carbide phases was shown to depend on the presence of a long chain diol and the reaction temperature. Confirmation of the iron carbide phases and structural characterization was made by X-ray diffraction (XRD) and Mössbauer spectroscopy. Particle morphology was characterized by transmission electron microscopy (TEM) and HR-TEM and the magnetic properties were measured with magnetometry (VSM). The sample with the Fe3C phase shows a ferromagnetic behavior with a magnetization of 139 emu g-1 under a 30 kOe applied field. The simple methodology presented here for producing iron carbide nanoplatelets has promising application in the biomedical and catalyst industries.
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Affiliation(s)
- Frank M Abel
- Department of Physics and Astronomy, University of Delaware Newark DE 19716 USA
| | - Shirin Pourmiri
- Department of Physics and Astronomy, University of Delaware Newark DE 19716 USA
| | - Georgia Basina
- Department of Chemical Engineering, Khalifa University of Science and Technology, Petroleum Institute P. O. Box 2533 Abu Dhabi United Arab Emirates
| | - Vasileios Tzitzios
- Department of Chemical Engineering, Khalifa University of Science and Technology, Petroleum Institute P. O. Box 2533 Abu Dhabi United Arab Emirates
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos Athens 15310 Greece
| | - Eamonn Devlin
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos Athens 15310 Greece
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11
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Tzitzios V, Dimos K, Lelidis I, Boukos NK, Wadi VS, Basina G, Nounesis G, Alhassan SM. Sulfur–oleyl amine platelet derivatives with liquid crystalline behavior. RSC Adv 2018; 8:41480-41483. [PMID: 35559320 PMCID: PMC9091870 DOI: 10.1039/c8ra08325h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 10/08/2018] [Accepted: 11/29/2018] [Indexed: 11/29/2022] Open
Abstract
A novel sulfur-based platelet derivative was synthesized by reacting elemental sulfur with oleyl amine. The sulfur–oleyl amine (S–OA) derivative has an ionic salt form, layered morphology and forms a highly lamellar structure. Polarized optical microscopy (POM) clearly shows the birefringent lyotropic liquid crystalline behavior of the S–OA platelets dispersions. A novel sulfur-based platelet derivative was synthesized by reacting elemental sulfur with oleyl amine.![]()
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Affiliation(s)
- Vasileios Tzitzios
- Department of Chemical Engineering
- Khalifa University of Science and Technology
- Petroleum Institute
- Abu Dhaabi
- United Arab Emirates
| | | | - Ioannis Lelidis
- Department of Physics
- National and Kapodistrian University of Athens
- 15784 Athens
- Greece
| | - Nikos K. Boukos
- Institute of Nanoscience and Nanotechnology
- NCSR Demokritos
- Athens
- Greece
| | - Vijay S. Wadi
- Department of Chemical Engineering
- Khalifa University of Science and Technology
- Petroleum Institute
- Abu Dhaabi
- United Arab Emirates
| | - Georgia Basina
- Department of Chemical Engineering
- Khalifa University of Science and Technology
- Petroleum Institute
- Abu Dhaabi
- United Arab Emirates
| | - George Nounesis
- Biomolecular Physics Laboratory
- NCSR Demokritos
- 15310 Athens
- Greece
| | - Saeed M. Alhassan
- Department of Chemical Engineering
- Khalifa University of Science and Technology
- Petroleum Institute
- Abu Dhaabi
- United Arab Emirates
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12
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Tzitzios V, Basina G, Tzitzios N, Alexandrakis V, Hu X, Hadjipanayis G. Direct liquid phase synthesis of ordered L1 0 FePt colloidal particles with high coercivity using an Au nanoparticle seeding approach. NEW J CHEM 2016. [DOI: 10.1039/c6nj01801g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
L10 ordered FePt nanoparticles that reveal an enhanced coercive field were synthesized following a liquid phase approach using Au nanoparticles as seeds.
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Affiliation(s)
- Vasileios Tzitzios
- Physics and Astronomy
- University of Delaware
- Newark
- USA
- Institute of Nanoscience and Nanotechnology
| | - Georgia Basina
- Institute of Nanoscience and Nanotechnology
- National Centre for Scientific Research “Demokritos”
- Aghia Paraskevi
- Attiki 153 10
- Greece
| | - Nikolaos Tzitzios
- Department of Materials Science and Engineering
- University of Ioannina
- Ioannina 45110
- Greece
| | - Vasileios Alexandrakis
- Institute of Nanoscience and Nanotechnology
- National Centre for Scientific Research “Demokritos”
- Aghia Paraskevi
- Attiki 153 10
- Greece
| | - Xiaocao Hu
- Department of Materials Science and Engineering
- University of Delaware
- Newark
- USA
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Rožič B, Tzitzios V, Karatairi E, Tkalec U, Nounesis G, Kutnjak Z, Cordoyiannis G, Rosso R, Virga EG, Muševič I, Kralj S. Theoretical and experimental study of the nanoparticle-driven blue phase stabilisation. Eur Phys J E Soft Matter 2011; 34:17. [PMID: 21340674 DOI: 10.1140/epje/i2011-11017-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/17/2011] [Indexed: 05/30/2023]
Abstract
We have studied theoretically and experimentally the effects of various types of nanoparticles (NPs) on the temperature stability range [Formula: see text] T (BP) of liquid-crystalline (LC) blue phases. Using a mesoscopic Landau-de Gennes type approach we obtain that the defect core replacement (DCR) mechanism yields in the diluted regime [Formula: see text] T (BP)(x) [Formula: see text] 1/(1 - xb) , where x stands for the concentration of NPs and b is a constant. Our calculations suggest that the DCR mechanism is efficient if a local NP environment resembles the core structure of disclinations, which represent the characteristic property of BP structures. These predictions are in line with high-resolution ac calorimetry and optical polarising microscopy experiments using the CE8 LC and CdSe or aerosil NPs. In mixtures with CdSe NPs of 3.5nm diameter and hydrophobic coating the BPIII stability range has been extended up to 20K. On the contrary, the effect of aerosil silica nanoparticles of 7.0nm diameter and hydrophilic coating is very weak.
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Affiliation(s)
- B Rožič
- Condensed Matter Physics Department, Jožef Stefan Institute, Jamova cesta 39, 1000, Ljubljana, Slovenia
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14
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Basina G, Mountrichas G, Devlin E, Boukos N, Niarchos D, Petridis D, Pispas S, Tzitzios V. Synthesis and magnetic properties of Fe3O4 nanoparticles coated with biocompatible double hydrophilic block copolymer. J Nanosci Nanotechnol 2009; 9:4753-4759. [PMID: 19928145 DOI: 10.1166/jnn.2009.1275] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fe3O4 nanoparticles coated with double hydrophilic biocompatible poly(sodium(2-sulfamate-3-carboxylate)isoprene)-b-poly(ethylene oxide) block copolymer were prepared by a one step precipitation method. The magnetic nanoparticles have 15 nm mean diameter (TEM), 68 nm hydrodynamic diameter, -30.10 mV zeta-potential and form very stable dispersion in aqueous media. Structural characterization using powder XRD and Mössbauer spectroscopy establish the magnetite phase, while thermogravimetric analysis and FT-IR spectroscopy confirm the presence of the block copolymer on the nanoparticles surface. The magnetic properties were determined using a vibrating sample magnetometer (VSM) at room temperature and reveal superparamagnetic behavior while the composite materials shows high saturation magnetization up to 67.7 emu/gr.
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Affiliation(s)
- G Basina
- Institute of Materials Science, N.C.S.R. "Demokritos" Agia Paraskevi, 15310 Athens, Greece
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15
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Tzitzios V, Georgakilas V, Zafiropoulou I, Boukos N, Basina G, Niarchos D, Petridis D. A general chemical route for the synthesis of capped nanocrystalline materials. J Nanosci Nanotechnol 2008; 8:3117-3122. [PMID: 18681056 DOI: 10.1166/jnn.2008.078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Noble metals, magnetic and semiconducting nanocrystalline materials have been synthesized via the thermolytic decomposition of inorganic metal salts, at high temperature, in commercial oleyl amine. The oleyl amine acts as high boiling point coordinating solvent, capping agent and, when required, as reducing agent. The crystal structure and morphology of the nanostructured materials have been studied with powder X-ray analysis (XRD) and transmission electron microscopy (TEM). The particles are well dispersed in non polar solvents such as hexane, toluene and chloroform and have uniform morphology.
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Affiliation(s)
- V Tzitzios
- Institute of Materials Science, NCSR Demokritos, Athens, Greece
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Zboril R, Bakandritsos A, Mashlan M, Tzitzios V, Dallas P, Trapalis C, Petridis D. One-step solid state synthesis of capped γ-Fe(2)O(3) nanocrystallites. Nanotechnology 2008; 19:095602. [PMID: 21817677 DOI: 10.1088/0957-4484/19/9/095602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The thermally induced solid state synthesis of soluble organophilic maghemite (γ-Fe(2)O(3)) nanocrystallites is described. The solvent-free one-step synthesis involves the reaction in the melt state of Fe(NO)(3)·9H(2)O and RCOOH (R = C(11)H(23), C(15)H(31)) at 240 °C. The method yields well-crystallized nanoparticles of γ-Fe(2)O(3) functionalized with the corresponding aliphatic acid. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) observations reveal composite particles with faceted magnetic cores and average size of 20 nm, which are well capped with the surrounding organic sheath. The Fourier transform infrared (FT-IR) spectra and thermal analysis suggest a bimodal configuration of the organic shell including chemically coordinated and physisorbed molecules of aliphatic acid. The chemical bonding of the carboxylate groups to the surface iron atoms is also indicated by a paramagnetic doublet with unchanged area in the variable temperature Mössbauer spectra. The spinel γ-Fe(2)O(3) particles exhibit perfect structural and magnetic ordering, including the almost ideal ratio of octahedral to tetrahedral positions (5/3) and very low degree of spin canting, as confirmed by in-field Mössbauer spectroscopy. Magnetic measurements demonstrate the suitable properties required in various (bio)magnetic applications like superparamagnetic behavior at room temperature, high saturation magnetization achievable at low applied fields and suppressed magnetic interactions.
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Affiliation(s)
- R Zboril
- Department of Physical Chemistry and Nanomaterials Research Centre, Palacky University, Svobody 26, 77146 Olomouc, Czech Republic
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Tzitzios V, Basina G, Gjoka M, Boukos N, Niarchos D, Devlin E, Petridis D. The effect of Mn doping in FePt nanoparticles on the magnetic properties of the L1(0) phase. Nanotechnology 2006; 17:4270-4273. [PMID: 21727570 DOI: 10.1088/0957-4484/17/16/044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
FePtMn nanoparticles with a narrow size distribution and an average diameter of 3 nm were synthesized by the chemical reduction of Fe(acac)(3) and Pt(acac)(2) by NaBH(4) and the thermal decomposition of Mn(2)(CO)(10) in phenyl ether. The as-made nanoparticles have a disordered face-centred cubic (fcc) structure, which transformed after thermal treatment at 650 °C to an ordered face-centred tetragonal (fct) structure, possessing coercivity values up to 13.7 kOe at room temperature. The coercivity of the annealed samples depends on the amount of Mn added to the reaction mixture, with the coercive field increasing significantly with the partial substitution of Pt by Mn, while the partial substitution of Fe by Mn does not affect the magnetic properties strongly.
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Affiliation(s)
- V Tzitzios
- Institute of Materials Science, NCSR 'Demokritos', Agia Paraskevi 15310 Athens, Greece
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Angelidis TN, Tzitzios V. Promotion of the Catalytic Activity of a Ag/Al2O3Catalyst for N2O Decomposition by the Addition of Rh. A Comparative Activity and Kinetic Study. Ind Eng Chem Res 2003. [DOI: 10.1021/ie020533b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Affiliation(s)
- T. N. Angelidis
- Laboratory of General and Inorganic Chemical Technology, Department of Chemistry (Box 114), Aristotle University, GR 54006, Thessaloniki, Greece
| | - D. Rosopoulou
- Laboratory of General and Inorganic Chemical Technology, Department of Chemistry (Box 114), Aristotle University, GR 54006, Thessaloniki, Greece
| | - V. Tzitzios
- Laboratory of General and Inorganic Chemical Technology, Department of Chemistry (Box 114), Aristotle University, GR 54006, Thessaloniki, Greece
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