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Prof. Costas Charitidis
School of Chemical Engineering, National Technical University of Athens

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Short Biography

Dr. Costas Charitidis is a professor at the School of Chemical Engineering of NTUA, with extensive R&D experience through collaborations with international research centres. He is a referee in international scientific journals; evaluator and scientific advisor of R&D projects; and participant in European and National funded R&D projects. His research activity is complemented by over 170 papers in international journals (150 ISI) and conferences, a large number of lectures as an invited speaker, and over 2200 citations (h-index of 34).

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Journal article
Published: 12 August 2021 in Ceramics International
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A systematic study on the effect of the electrochemical exfoliation of graphite was conducted to provide new insights on the structure and material properties. Graphene-like structures are produced at scale currently using the wet chemical approaches, which is usually followed by an additional reduction step. The electrochemical exfoliation constitutes a promising alternative method for green, fast, and safe industrial exploitation, due to its low cost, mild conditions, basic equipment requirement and eco-friendlier electrolytes. Additionally, crystal structure of graphene related materials demonstrates less defective sights due to the high speed of exfoliation. A thorough investigation was conducted on critical parameters of the electrochemical process. The parameters of concentration, voltage, temperature and sonication assistance were studied using the randomized block design approach for various electrolytes. After the evaluation and screening of the materials with several characterization techniques, three optimization routes were selected, which included a modified Hummers' method, exfoliation based on the surface energy of pure DMF, and violent pH neutralization. The production of graphene oxide nanoplatelets was achieved, with high oxidation rates, high crystallinity and limited imperfections. The materials were consisted of less than 10 layers and up to 5 layers as demonstrated by the low crystallite size, which was also demonstrated for GO that underwent post-treatment optimization. Higher yields were achieved with electrolytes known for their strong oxidative effect, while the hydrogen peroxide electrolyte and the ionic liquid demonstrated lower exfoliation rates.

ACS Style

Georgios Konstantopoulos; Eleni Fotou; Afroditi Ntziouni; Konstantinos Kordatos; Costas A. Charitidis. A systematic study of electrolyte effect on exfoliation efficiency and green synthesis of graphene oxide. Ceramics International 2021, 1 .

AMA Style

Georgios Konstantopoulos, Eleni Fotou, Afroditi Ntziouni, Konstantinos Kordatos, Costas A. Charitidis. A systematic study of electrolyte effect on exfoliation efficiency and green synthesis of graphene oxide. Ceramics International. 2021; ():1.

Chicago/Turabian Style

Georgios Konstantopoulos; Eleni Fotou; Afroditi Ntziouni; Konstantinos Kordatos; Costas A. Charitidis. 2021. "A systematic study of electrolyte effect on exfoliation efficiency and green synthesis of graphene oxide." Ceramics International , no. : 1.

Review
Published: 04 July 2021 in Molecules
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Self-assembling peptides and carbon nanomaterials have attracted great interest for their respective potential to bring innovation in the biomedical field. Combination of these two types of building blocks is not trivial in light of their very different physico-chemical properties, yet great progress has been made over the years at the interface between these two research areas. This concise review will analyze the latest developments at the forefront of research that combines self-assembling peptides with carbon nanostructures for biological use. Applications span from tissue regeneration, to biosensing and imaging, and bioelectronics.

ACS Style

Petr Rozhin; Costas Charitidis; Silvia Marchesan. Self-Assembling Peptides and Carbon Nanomaterials Join Forces for Innovative Biomedical Applications. Molecules 2021, 26, 4084 .

AMA Style

Petr Rozhin, Costas Charitidis, Silvia Marchesan. Self-Assembling Peptides and Carbon Nanomaterials Join Forces for Innovative Biomedical Applications. Molecules. 2021; 26 (13):4084.

Chicago/Turabian Style

Petr Rozhin; Costas Charitidis; Silvia Marchesan. 2021. "Self-Assembling Peptides and Carbon Nanomaterials Join Forces for Innovative Biomedical Applications." Molecules 26, no. 13: 4084.

Journal article
Published: 23 June 2021 in Chemosensors
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Silver nanoparticles (AgNPs) exert profound physicochemical, biological, and antimicrobial properties, therefore, they have been extensively studied for a variety of applications such as food packaging and cultural heritage protection. However, restrictions in their stability, aggregation phenomena, and toxicity limit their extensive use. Hence, the use of functional substrates that promote the silver nanoparticles’ growth and allow the formation of uniform-sized, evenly distributed, as well as stable nanoparticles, has been suggested. This study reports on the fabrication and the characterization of hydrophilic polymer spheres including nanoparticles with intrinsic antifungal properties. Poly (methacrylic acid) microspheres were synthesized, employing the distillation precipitation method, to provide monodisperse spherical substrates for the growth of silver nanoparticles, utilizing the co-precipitation of silver nitrate in aqueous media. The growth and the aggregation potential of the silver nanoparticles were studied, whereas the antifungal activity of the produced nanostructures was evaluated against the black mold-causing fungus Aspergillus niger. The produced structures exhibit dose-dependent antifungal activity. Therefore, they could potentially be employed for the protection and preservation of cultural heritage artifacts and considered as new agents for food protection from fungal contamination during storage.

ACS Style

Panagiotis Kainourgios; Leto-Aikaterini Tziveleka; Ioannis Kartsonakis; Efstathia Ioannou; Vassilios Roussis; Costas Charitidis. Silver Nanoparticles Grown on Cross-Linked Poly (Methacrylic Acid) Microspheres: Synthesis, Characterization, and Antifungal Activity Evaluation. Chemosensors 2021, 9, 152 .

AMA Style

Panagiotis Kainourgios, Leto-Aikaterini Tziveleka, Ioannis Kartsonakis, Efstathia Ioannou, Vassilios Roussis, Costas Charitidis. Silver Nanoparticles Grown on Cross-Linked Poly (Methacrylic Acid) Microspheres: Synthesis, Characterization, and Antifungal Activity Evaluation. Chemosensors. 2021; 9 (7):152.

Chicago/Turabian Style

Panagiotis Kainourgios; Leto-Aikaterini Tziveleka; Ioannis Kartsonakis; Efstathia Ioannou; Vassilios Roussis; Costas Charitidis. 2021. "Silver Nanoparticles Grown on Cross-Linked Poly (Methacrylic Acid) Microspheres: Synthesis, Characterization, and Antifungal Activity Evaluation." Chemosensors 9, no. 7: 152.

Journal article
Published: 30 April 2021 in International Journal of Non-Linear Mechanics
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We present a constitutive framework for modeling the nonlinear elastic behavior of α-Germanium (Ge). Starting with all possible phase changes Ge sustains under compression, we correspond to each space group of every phase the arithmetic symmetry group by viewing Ge as a multilattice. We then focus on the mother α phase of Ge. Confining ourselves to weak transformation neighborhoods and adopting the Cauchy–Born rule we work with the classical symmetries of continuum mechanics. Since there is no available representation theory for the symmetry group of α-Ge, we use integrity basis theory to find the most general expression for the arguments of the energy. Using energy’s expression we evaluate the stress tensor in its most general form. We then study two problems of increasing difficulty: simple tension/compression and anti-plane shear. For the first class of problems we give closed form solutions, while the anti-plane shear problem complicates the equations dramatically; we give conditions for the solvability of the field equations ruling the shift vector.

ACS Style

D. Sfyris; D.A. Dragatogiannis; C. Charitidis. Nonlinear elastic constitutive modeling of α-Ge. International Journal of Non-Linear Mechanics 2021, 134, 103737 .

AMA Style

D. Sfyris, D.A. Dragatogiannis, C. Charitidis. Nonlinear elastic constitutive modeling of α-Ge. International Journal of Non-Linear Mechanics. 2021; 134 ():103737.

Chicago/Turabian Style

D. Sfyris; D.A. Dragatogiannis; C. Charitidis. 2021. "Nonlinear elastic constitutive modeling of α-Ge." International Journal of Non-Linear Mechanics 134, no. : 103737.

Journal article
Published: 29 April 2021 in Polymers
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This study aims to examine how core–shell super absorbent polymers (SAPs) can be effective in relation to recycling processes by using them as triggerable materials in coating binders. Super absorbent polymers are partially cross-linked, three-dimensional polymer networks that can absorb and retain water. Coatings based on an acrylic binder, including SAPs, were applied onto plastic substrates of acrylonitrile–butadiene–styrene/polycarbonate. The incorporation of 1 wt.% and 5 wt.% SAPs into the coatings resulted in the debonding of the coatings from the substrates under a steam treatment. The trigger mechanism for the core–shell hydrophilic SAPs relies on the different abilities of the core and shell materials to be swollen. Therefore, under the influence of steam, SAPs can enhance their shape due to water absorption and the breaking of the inorganic shell. This results in the reduction of the attachment between the primer layer and both the top coating and the substrate, thus enabling the detachment of the top coating from the corresponding substrate. The obtained results from this study can be considered as potential formulations for plastic recycling applications in industries.

ACS Style

Ioannis Kartsonakis; Panagiotis Goulis; Costas Charitidis. Triggerable Super Absorbent Polymers for Coating Debonding Applications. Polymers 2021, 13, 1432 .

AMA Style

Ioannis Kartsonakis, Panagiotis Goulis, Costas Charitidis. Triggerable Super Absorbent Polymers for Coating Debonding Applications. Polymers. 2021; 13 (9):1432.

Chicago/Turabian Style

Ioannis Kartsonakis; Panagiotis Goulis; Costas Charitidis. 2021. "Triggerable Super Absorbent Polymers for Coating Debonding Applications." Polymers 13, no. 9: 1432.

Paper
Published: 12 April 2021 in Nanoscale Advances
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Schematic representation of the QSAR modeling workflow in this study, which produced the model predicting genotoxicity of multi-walled carbon nanotubes (MWCNTs).

ACS Style

Marianna Kotzabasaki; Iason Sotiropoulos; Constantinos Charitidis; Haralambos Sarimveis. Machine learning methods for multi-walled carbon nanotubes (MWCNT) genotoxicity prediction. Nanoscale Advances 2021, 3, 3167 -3176.

AMA Style

Marianna Kotzabasaki, Iason Sotiropoulos, Constantinos Charitidis, Haralambos Sarimveis. Machine learning methods for multi-walled carbon nanotubes (MWCNT) genotoxicity prediction. Nanoscale Advances. 2021; 3 (11):3167-3176.

Chicago/Turabian Style

Marianna Kotzabasaki; Iason Sotiropoulos; Constantinos Charitidis; Haralambos Sarimveis. 2021. "Machine learning methods for multi-walled carbon nanotubes (MWCNT) genotoxicity prediction." Nanoscale Advances 3, no. 11: 3167-3176.

Review
Published: 06 February 2021 in Applied Sciences
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The management of energy consumption in the building sector is of crucial concern for modern societies. Fossil fuels' reduced availability, along with the environmental implications they cause, emphasize the necessity for the development of new technologies using renewable energy resources. Taking into account the growing resource shortages, as well as the ongoing deterioration of the environment, the building energy performance improvement using phase change materials (PCMs) is considered as a solution that could balance the energy supply together with the corresponding demand. Thermal energy storage systems with PCMs have been investigated for several building applications as they constitute a promising and sustainable method for reduction of fuel and electrical energy consumption, while maintaining a comfortable environment in the building envelope. These compounds can be incorporated into building construction materials and provide passive thermal sufficiency, or they can be used in heating, ventilation, and air conditioning systems, domestic hot water applications, etc. This study presents the principles of latent heat thermal energy storage systems with PCMs. Furthermore, the materials that can be used as PCMs, together with the most effective methods for improving their thermal performance, as well as various passive applications in the building sector, are also highlighted. Finally, special attention is given to the encapsulated PCMs that are composed of the core material, which is the PCM, and the shell material, which can be inorganic or organic, and their utilization inside constructional materials.

ACS Style

Christina Podara; Ioannis Kartsonakis; Costas Charitidis. Towards Phase Change Materials for Thermal Energy Storage: Classification, Improvements and Applications in the Building Sector. Applied Sciences 2021, 11, 1490 .

AMA Style

Christina Podara, Ioannis Kartsonakis, Costas Charitidis. Towards Phase Change Materials for Thermal Energy Storage: Classification, Improvements and Applications in the Building Sector. Applied Sciences. 2021; 11 (4):1490.

Chicago/Turabian Style

Christina Podara; Ioannis Kartsonakis; Costas Charitidis. 2021. "Towards Phase Change Materials for Thermal Energy Storage: Classification, Improvements and Applications in the Building Sector." Applied Sciences 11, no. 4: 1490.

Journal article
Published: 13 January 2021 in Applied Sciences
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Cementitious structures have prevailed worldwide and are expected to exhibit further growth in the future. Nevertheless, cement cracking is an issue that needs to be addressed in order to enhance structure durability and sustainability especially when exposed to aggressive environments. The purpose of this work was to examine the impact of the Superabsorbent Polymers (SAPs) incorporation into cementitious composite materials (mortars) with respect to their structure (hybrid structure consisting of organic core—inorganic shell) and evaluate the microstructure and self-healing properties of the obtained mortars. The applied SAPs were tailored to maintain their functionality in the cementitious environment. Control and mortar/SAPs specimens with two different SAPs concentrations (1 and 2% bwoc) were molded and their mechanical properties were determined according to EN 196-1, while their microstructure and self-healing behavior were evaluated via microCT. Compressive strength, a key property for mortars, which often degrades with SAPs incorporation, in this work, practically remained intact for all specimens. This is coherent with the porosity reduction and the narrower range of pore size distribution for the mortar/SAPs specimens as determined via microCT. Moreover, the self-healing behavior of mortar-SAPs specimens was enhanced up to 60% compared to control specimens. Conclusively, the overall SAPs functionality in cementitious-based materials was optimized.

ACS Style

Irene A. Kanellopoulou; Ioannis A. Kartsonakis; Costas A. Charitidis. The Effect of Superabsorbent Polymers on the Microstructure and Self-Healing Properties of Cementitious-Based Composite Materials. Applied Sciences 2021, 11, 700 .

AMA Style

Irene A. Kanellopoulou, Ioannis A. Kartsonakis, Costas A. Charitidis. The Effect of Superabsorbent Polymers on the Microstructure and Self-Healing Properties of Cementitious-Based Composite Materials. Applied Sciences. 2021; 11 (2):700.

Chicago/Turabian Style

Irene A. Kanellopoulou; Ioannis A. Kartsonakis; Costas A. Charitidis. 2021. "The Effect of Superabsorbent Polymers on the Microstructure and Self-Healing Properties of Cementitious-Based Composite Materials." Applied Sciences 11, no. 2: 700.

Journal article
Published: 18 December 2020 in Materials & Design
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Thermoplastic nanocomposites were fabricated in order to deliver a suitable material for thermal management devices, commonly processed by injection molding or 3D printing. Scalable manufacturing of Carbon Nanotubes (CNTs) and multi-functional polymers with good thermal conductivity and ease of handling was demonstrated in the present study. The standard grade polyethylene reinforced with CNTs, was formed by melt mixing. Polyethylene glycol was used for concentrating CNTs in a masterbatch for its plasticizing properties, ensuring safe handling and even dispersion of CNTs. Through characterization of morphology and thermal properties, an interconnected CNTs network was established, which enhanced the heat transfer at high concentration by changing the main conduction path from polymer crystal lattice to CNTs conductive network. Moreover, it was shown that modification in the matrix crystallinity is key to maximize the phonon and electron conduction interfaces and achieve advances in thermal conductivity beyond 68% and 100% achieved for 15 wt% content of CNTs compared to neat PE and [email protected] matrices, respectively, within this study.

ACS Style

Georgios Konstantopoulos; Panagiotis Maroulas; Dimitrios A. Dragatogiannis; Stefanos Koutsoumpis; Apostolos Kyritsis; Costas A. Charitidis. The effect of interfacial resistance and crystallinity on heat transfer mechanism in carbon nanotube reinforced polyethylene. Materials & Design 2020, 199, 109420 .

AMA Style

Georgios Konstantopoulos, Panagiotis Maroulas, Dimitrios A. Dragatogiannis, Stefanos Koutsoumpis, Apostolos Kyritsis, Costas A. Charitidis. The effect of interfacial resistance and crystallinity on heat transfer mechanism in carbon nanotube reinforced polyethylene. Materials & Design. 2020; 199 ():109420.

Chicago/Turabian Style

Georgios Konstantopoulos; Panagiotis Maroulas; Dimitrios A. Dragatogiannis; Stefanos Koutsoumpis; Apostolos Kyritsis; Costas A. Charitidis. 2020. "The effect of interfacial resistance and crystallinity on heat transfer mechanism in carbon nanotube reinforced polyethylene." Materials & Design 199, no. : 109420.

Journal article
Published: 23 November 2020 in Fibers
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The aim of this study is to synthesize an organic core-shell co-polymer with a different glass transition temperature (Tg) between the core and the shell that can be used for several applications such as the selective debonding of coatings or the release of encapsulated materials. The co-polymer was synthesized using free radical polymerization and was characterized with respect to its morphology, composition and thermal behavior. The obtained results confirmed the successful synthesis of the co-polymer copolymer poly(methyl methacrylate)@poly(methacrylic acid-co-ethylene glycol dimethacrylate), [email protected](MAA-co-EGDMA), which can be used along with water-based solvents. Furthermore, the Tg of the polymer’s core PMMA was 104 °C, while the Tg of the shell P(MAA-co-EGDMA) was 228 °C, making it appropriate for a wide variety of applications. It is worth mentioning that by following this specific experimental procedure, methacrylic acid was copolymerized in water, as the shell of the copolymer, without forming a gel-like structure (hydrogel), as happens when a monomer is polymerized in aqueous media, such as in the case of super-absorbent polymers. Moreover, the addition and subsequent polymerization of the monomer methyl methacrylate (MAA) into the mixture of the already polymerized PMMA resulted in a material that was uniform in size, without any agglomerations or sediments.

ACS Style

Panagiotis Goulis; Ioannis A. Kartsonakis; Costas A. Charitidis. Synthesis and Characterization of a Core-Shell Copolymer with Different Glass Transition Temperatures. Fibers 2020, 8, 71 .

AMA Style

Panagiotis Goulis, Ioannis A. Kartsonakis, Costas A. Charitidis. Synthesis and Characterization of a Core-Shell Copolymer with Different Glass Transition Temperatures. Fibers. 2020; 8 (11):71.

Chicago/Turabian Style

Panagiotis Goulis; Ioannis A. Kartsonakis; Costas A. Charitidis. 2020. "Synthesis and Characterization of a Core-Shell Copolymer with Different Glass Transition Temperatures." Fibers 8, no. 11: 71.

Journal article
Published: 17 October 2020 in Materials Science and Engineering: C
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Additive manufacturing holds promise for the fabrication of three-dimensional scaffolds with precise geometry, to serve as substrates for the guided regeneration of natural tissue. In this work, a bioinspired approach is adopted for the synthesis of hybrid hydroxyapatite hydrogels, which were subsequently printed to form 3D scaffolds for bone tissue engineering applications. These hydrogels consist of hydroxyapatite nanocrystals, biomimetically synthesized in the presence of both chitosan and l-arginine. To improve their mechanical properties, chemical crosslinking was performed using a natural crosslinking agent (genipin), and their rheology was modified by employing an acetic acid/gelatin solution. Regarding the 3D printing process, several parameters (flow, infill and perimeter speed) were studied in order to accurately produce scaffolds with predesigned geometry and micro-architecture, while also applying low printing temperature (15 °C). Following the printing procedure, the 3D scaffolds were freeze dried in order to remove the entrapped solvents and therefore, obtain a porous interconnected network. Evaluation of porosity was performed using micro-computed tomography and nanomechanical properties were assessed through nanoindentation. Results of both characterization techniques, showed that the scaffolds' porosity as well as their modulus values, fall within the corresponding range of the respective values of cancellous bone. The biocompatibility of the 3D printed scaffolds was assessed using MG63 human osteosarcoma cells for 7 days of culturing. Cell viability was evaluated by MTT assay as well as double staining and visualized under fluorescence microscopy, while cell morphology was analyzed through scanning electron microscopy. Biocompatibility tests, revealed that the scaffolds constitute a cell-friendly environment, allowed them to adhere on the scaffolds' surface, increase their population and maintain high levels of viability.

ACS Style

K. Zafeiris; D. Brasinika; A. Karatza; Elias Koumoulos; I.K. Karoussis; K. Kyriakidou; C.A. Charitidis. Additive manufacturing of hydroxyapatite–chitosan–genipin composite scaffolds for bone tissue engineering applications. Materials Science and Engineering: C 2020, 119, 111639 .

AMA Style

K. Zafeiris, D. Brasinika, A. Karatza, Elias Koumoulos, I.K. Karoussis, K. Kyriakidou, C.A. Charitidis. Additive manufacturing of hydroxyapatite–chitosan–genipin composite scaffolds for bone tissue engineering applications. Materials Science and Engineering: C. 2020; 119 ():111639.

Chicago/Turabian Style

K. Zafeiris; D. Brasinika; A. Karatza; Elias Koumoulos; I.K. Karoussis; K. Kyriakidou; C.A. Charitidis. 2020. "Additive manufacturing of hydroxyapatite–chitosan–genipin composite scaffolds for bone tissue engineering applications." Materials Science and Engineering: C 119, no. : 111639.

Editorial
Published: 02 October 2020 in Frontiers in Chemistry
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Editorial: Recent Trends in Optical and Mechanical Characterization of Nanomaterials

ACS Style

Stefan G. Stanciu; Loredana Latterini; Costas A. Charitidis. Editorial: Recent Trends in Optical and Mechanical Characterization of Nanomaterials. Frontiers in Chemistry 2020, 8, 564014 .

AMA Style

Stefan G. Stanciu, Loredana Latterini, Costas A. Charitidis. Editorial: Recent Trends in Optical and Mechanical Characterization of Nanomaterials. Frontiers in Chemistry. 2020; 8 ():564014.

Chicago/Turabian Style

Stefan G. Stanciu; Loredana Latterini; Costas A. Charitidis. 2020. "Editorial: Recent Trends in Optical and Mechanical Characterization of Nanomaterials." Frontiers in Chemistry 8, no. : 564014.

Journal article
Published: 21 September 2020 in Applied Sciences
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In the present work, an assessment of the corrosion behavior of mild steel in the presence of an organic corrosion inhibitor loaded into hybrid composite materials is performed. Hybrid organic–inorganic nanocontainers based on cerium and titanium oxides were fabricated via a combination of radical polymerization together with the coprecipitation method and sol-gel technique. The corrosion inhibition role of these hybrid materials loaded with an inhibitor is considered. A set of characterization assays addressing morphology, composition and structural aspects of the exposed steels is illustrated, along with electrochemical evaluations. The results reveal enhanced stimuli responsive anticorrosion ability of the produced hybrid materials. Furthermore, upon corrosion, new compounds are formed onto the exposed areas of the treated metals. The conducted experiments shed light on the corrosion mechanisms for steel alloys as well as the actuation of the fabricated composite materials, paving the way for future developments in this area.

ACS Style

Ioannis A. Kartsonakis; Costas A. Charitidis. Corrosion Protection Evaluation of Mild Steel: The Role of Hybrid Materials Loaded with Inhibitors. Applied Sciences 2020, 10, 6594 .

AMA Style

Ioannis A. Kartsonakis, Costas A. Charitidis. Corrosion Protection Evaluation of Mild Steel: The Role of Hybrid Materials Loaded with Inhibitors. Applied Sciences. 2020; 10 (18):6594.

Chicago/Turabian Style

Ioannis A. Kartsonakis; Costas A. Charitidis. 2020. "Corrosion Protection Evaluation of Mild Steel: The Role of Hybrid Materials Loaded with Inhibitors." Applied Sciences 10, no. 18: 6594.

Journal article
Published: 18 September 2020 in Polymers
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Life cycle assessment is a methodology to assess environmental impacts associated with a product or system/process by accounting resource requirements and emissions over its life cycle. The life cycle consists of four stages: material production, manufacturing, use, and end-of-life. This study highlights the need to conduct life cycle assessment (LCA) early in the new product development process, as a means to assess and evaluate the environmental impacts of (nano)enhanced carbon fibre-reinforced polymer (CFRP) prototypes over their entire life cycle. These prototypes, namely SleekFast sailing boat and handbrake lever, were manufactured by functionalized carbon fibre fabric and modified epoxy resin with multi-walled carbon nanotubes (MWCNTs). The environmental impacts of both have been assessed via LCA with a functional unit of ‘1 product piece’. Climate change has been selected as the key impact indicator for hotspot identification (kg CO2 eq). Significant focus has been given to the end-of-life phase by assessing different recycling scenarios. In addition, the respective life cycle inventories (LCIs) are provided, enabling the identification of resource hot spots and quantifying the environmental benefits of end-of-life options.

ACS Style

Fotini Petrakli; Anastasia Gkika; Alexandra Bonou; Panagiotis Karayannis; Elias Koumoulos; Dionisis Semitekolos; Aikaterini-Flora Trompeta; Nuno Rocha; Raquel Santos; Guy Simmonds; Glen Monaghan; Giorgio Valota; Guan Gong; Costas Charitidis. End-of-Life Recycling Options of (Nano)Enhanced CFRP Composite Prototypes Waste—A Life Cycle Perspective. Polymers 2020, 12, 2129 .

AMA Style

Fotini Petrakli, Anastasia Gkika, Alexandra Bonou, Panagiotis Karayannis, Elias Koumoulos, Dionisis Semitekolos, Aikaterini-Flora Trompeta, Nuno Rocha, Raquel Santos, Guy Simmonds, Glen Monaghan, Giorgio Valota, Guan Gong, Costas Charitidis. End-of-Life Recycling Options of (Nano)Enhanced CFRP Composite Prototypes Waste—A Life Cycle Perspective. Polymers. 2020; 12 (9):2129.

Chicago/Turabian Style

Fotini Petrakli; Anastasia Gkika; Alexandra Bonou; Panagiotis Karayannis; Elias Koumoulos; Dionisis Semitekolos; Aikaterini-Flora Trompeta; Nuno Rocha; Raquel Santos; Guy Simmonds; Glen Monaghan; Giorgio Valota; Guan Gong; Costas Charitidis. 2020. "End-of-Life Recycling Options of (Nano)Enhanced CFRP Composite Prototypes Waste—A Life Cycle Perspective." Polymers 12, no. 9: 2129.

Journal article
Published: 19 August 2020 in Bioengineering
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Bioinspired scaffolds mimicking natural bone-tissue properties holds great promise in tissue engineering applications towards bone regeneration. Within this work, a way to reinforce mechanical behavior of bioinspired bone scaffolds was examined by applying a physical crosslinking method. Scaffolds consisted of hydroxyapatite nanocrystals, biomimetically synthesized in the presence of collagen and l-arginine. Scaffolds were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), microcomputed tomography, and nanoindentation. Results revealed scaffolds with bone-like nanostructure and composition, thus an inherent enhanced cytocompatibility. Evaluation of porosity proved the development of interconnected porous network with bimodal pore size distribution. Mechanical reinforcement was achieved through physical crosslinking with riboflavin irradiation, and nanoindentation tests indicated that within the experimental conditions of 45% humidity and 37 °C, photo-crosslinking led to an increase in the scaffold’s mechanical properties. Elastic modulus and hardness were augmented, and specifically elastic modulus values were doubled, approaching equivalent values of trabecular bone. Cytocompatibility of the scaffolds was assessed using MG63 human osteosarcoma cells. Cell viability was evaluated by double staining and MTT assay, while attachment and morphology were investigated by SEM. The results suggested that scaffolds provided a cell friendly environment with high levels of viability, thus supporting cell attachment, spreading and proliferation.

ACS Style

Despoina Brasinika; Elias P. Koumoulos; Kyriaki Kyriakidou; Eleni Gkartzou; Maria Kritikou; Ioannis K. Karoussis; Costas A. Charitidis. Mechanical Enhancement of Cytocompatible 3D Scaffolds, Consisting of Hydroxyapatite Nanocrystals and Natural Biomolecules, Through Physical Cross-Linking. Bioengineering 2020, 7, 96 .

AMA Style

Despoina Brasinika, Elias P. Koumoulos, Kyriaki Kyriakidou, Eleni Gkartzou, Maria Kritikou, Ioannis K. Karoussis, Costas A. Charitidis. Mechanical Enhancement of Cytocompatible 3D Scaffolds, Consisting of Hydroxyapatite Nanocrystals and Natural Biomolecules, Through Physical Cross-Linking. Bioengineering. 2020; 7 (3):96.

Chicago/Turabian Style

Despoina Brasinika; Elias P. Koumoulos; Kyriaki Kyriakidou; Eleni Gkartzou; Maria Kritikou; Ioannis K. Karoussis; Costas A. Charitidis. 2020. "Mechanical Enhancement of Cytocompatible 3D Scaffolds, Consisting of Hydroxyapatite Nanocrystals and Natural Biomolecules, Through Physical Cross-Linking." Bioengineering 7, no. 3: 96.

Journal article
Published: 14 July 2020 in Materials
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Carbon Fibres (CFs) are widely used in textile-reinforced composites for the construction of lightweight, durable structures. Since their inert surface does not allow effective bonding with the matrix material, the surface treatment of fibres is suggested to improve the adhesion between the two. In the present study, different surface modifications are compared in terms of the mechanical enhancement that they can offer to the fibres. Two main advanced technologies have been investigated; namely, plasma treatment and electrochemical treatment. Specifically, active screen plasma and low-pressure plasma were compared. Regarding the electrochemical modification, electrochemical oxidation and electropolymerisation of monomer solutions of acrylic and methacrylic acids, acrylonitrile and N-vinyl pyrrolidine were tested for HTA-40 CFs. In order to assess the effects of the surface treatments, the morphology, the physicochemical properties, as well as the mechanical integrity of the fibres were investigated. The CF surface and polymeric matrix interphase adhesion in composites were also analysed. The improvement of the carbon fibre’s physical–mechanical properties was evident for the case of the active screen plasma treatment and the electrochemical oxidation.

ACS Style

Dionisis Semitekolos; Aikaterini-Flora Trompeta; Iryna Husarova; Tamara Man’Ko; Aleksandr Potapov; Ol'ga Romenskaya; Yana Liang; Xiaoying Li; Mauro Giorcelli; Hanshan Dong; Alberto Tagliaferro; Costas A. Charitidis. Comparative Physical–Mechanical Properties Assessment of Tailored Surface-Treated Carbon Fibres. Materials 2020, 13, 3136 .

AMA Style

Dionisis Semitekolos, Aikaterini-Flora Trompeta, Iryna Husarova, Tamara Man’Ko, Aleksandr Potapov, Ol'ga Romenskaya, Yana Liang, Xiaoying Li, Mauro Giorcelli, Hanshan Dong, Alberto Tagliaferro, Costas A. Charitidis. Comparative Physical–Mechanical Properties Assessment of Tailored Surface-Treated Carbon Fibres. Materials. 2020; 13 (14):3136.

Chicago/Turabian Style

Dionisis Semitekolos; Aikaterini-Flora Trompeta; Iryna Husarova; Tamara Man’Ko; Aleksandr Potapov; Ol'ga Romenskaya; Yana Liang; Xiaoying Li; Mauro Giorcelli; Hanshan Dong; Alberto Tagliaferro; Costas A. Charitidis. 2020. "Comparative Physical–Mechanical Properties Assessment of Tailored Surface-Treated Carbon Fibres." Materials 13, no. 14: 3136.

Essay
Published: 12 July 2020 in Small
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Nanotechnology, as a mature enabling technology, has great potential to boost societal welfare. However, nanomaterials' current and foreseen applications raise serious concerns about their impact on human health and the environment. These concerns emerge because a reliable risk assessment in nanotechnology is yet to be achieved. The reasons for such a shortcoming are the inherent difficulties in characterizing nanomaterials properties. The interaction of characterization with modeling is an open issue and, due to overarching concerns about the reliability of research results, usually framed within the context of research integrity. This essay explores the connection between these different, but deeply intertwined concerns and the way they enable the production of responsible nanotechnology, i.e., nanotechnology devoted to societal welfare.

ACS Style

Ioannis Xiarchos; Athanasios K. Morozinis; Panagiotis Kavouras; Costas A. Charitidis. Nanocharacterization, Materials Modeling, and Research Integrity as Enablers of Sound Risk Assessment: Designing Responsible Nanotechnology. Small 2020, 16, e2001590 .

AMA Style

Ioannis Xiarchos, Athanasios K. Morozinis, Panagiotis Kavouras, Costas A. Charitidis. Nanocharacterization, Materials Modeling, and Research Integrity as Enablers of Sound Risk Assessment: Designing Responsible Nanotechnology. Small. 2020; 16 (36):e2001590.

Chicago/Turabian Style

Ioannis Xiarchos; Athanasios K. Morozinis; Panagiotis Kavouras; Costas A. Charitidis. 2020. "Nanocharacterization, Materials Modeling, and Research Integrity as Enablers of Sound Risk Assessment: Designing Responsible Nanotechnology." Small 16, no. 36: e2001590.

Journal article
Published: 17 June 2020 in Materials
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A methodology for designing the oxidative stabilization process of polyacrylonitrile (PAN) fibers is examined. In its core, this methodology is based on a model that describes the characteristic fiber length variation during thermal processing, through the de-convolution of three main contributors (i.e., entropic and chemical shrinkage and creep elongation). The model demonstrated an additional advantage of offering further insight into the physical and chemical phenomena taking place during the treatment. Validation of PAN-model prediction performance for different processing parameters was achieved as demonstrated by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). Τensile testing revealed the effect of processing parameters on fiber quality, while model prediction demonstrated that ladder polymer formation is accelerated at temperatures over 200 °C. Additionally, according the DSC and FTIR measurements predictions from the application of the model during stabilization seem to be more precise at high-temperature stabilization stages. It was shown that mechanical properties could be enhanced preferably by including a treatment step below 200 °C, before the initiation of cyclization reactions. Further confirmation was provided via Raman spectroscopy, which demonstrated that graphitic like planes are formed upon stabilization above 200 °C, and thus multistage stabilization is required to optimize synthesis of carbon fibers. Optical Microscopy proved that isothermal stabilization treatment did not severely alter the cross section geometry of PAN fiber monofilaments.

ACS Style

George Konstantopoulos; Spyros Soulis; Dimitrios Dragatogiannis; Costas Charitidis. Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization. Materials 2020, 13, 2749 .

AMA Style

George Konstantopoulos, Spyros Soulis, Dimitrios Dragatogiannis, Costas Charitidis. Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization. Materials. 2020; 13 (12):2749.

Chicago/Turabian Style

George Konstantopoulos; Spyros Soulis; Dimitrios Dragatogiannis; Costas Charitidis. 2020. "Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization." Materials 13, no. 12: 2749.

Journal article
Published: 26 May 2020 in Fibers
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The aim of this work is to review a possible correlation of composition, thermal processing, and recent alternative stabilization technologies to the mechanical properties. The chemical microstructure of polyacrylonitrile (PAN) is discussed in detail to understand the influence in thermomechanical properties during stabilization by observing transformation from thermoplastic to ladder polymer. In addition, relevant literature data are used to understand the comonomer composition effect on mechanical properties. Technologies of direct fiber heating by irradiation have been recently involved and hold promise to enhance performance, reduce processing time and energy consumption. Carbon fiber manufacturing can provide benefits by using higher comonomer ratios, similar to textile grade or melt-spun PAN, in order to cut costs derived from an acrylonitrile precursor, without suffering in regard to mechanical properties. Energy intensive processes of stabilization and carbonization remain a challenging field of research in order to reduce both environmental impact and cost of the wide commercialization of carbon fibers (CFs) to enable their broad application.

ACS Style

Spyridon Soulis; George Konstantopoulos; Elias P. Koumoulos; Costas A. Charitidis. Impact of Alternative Stabilization Strategies for the Production of PAN-Based Carbon Fibers with High Performance. Fibers 2020, 8, 1 .

AMA Style

Spyridon Soulis, George Konstantopoulos, Elias P. Koumoulos, Costas A. Charitidis. Impact of Alternative Stabilization Strategies for the Production of PAN-Based Carbon Fibers with High Performance. Fibers. 2020; 8 (6):1.

Chicago/Turabian Style

Spyridon Soulis; George Konstantopoulos; Elias P. Koumoulos; Costas A. Charitidis. 2020. "Impact of Alternative Stabilization Strategies for the Production of PAN-Based Carbon Fibers with High Performance." Fibers 8, no. 6: 1.

Preprint
Published: 26 May 2020
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A methodology is proposed for designing the stabilization process of polyacrylonitrile (PAN) fibers. In its core, this methodology is based on a model that describes the characteristic fiber length change during the treatment, through the de-convolution of the three main contributors (i.e. entropic shrinkage, creep, and chemical shrinkage). The model has the additional advantage of offering further insight into the physical and chemical phenomena taking place during the treatment. Validation of PAN-model prediction performance for different processing parameters was achieved as demonstrated by FTIR and DSC. Τensile testing revealed the effect of processing parameters on fiber quality, while model prediction demonstrated that ladder polymer formation is accelerated at temperatures over 200oC. Additionally, according the DSC and FTIR measurements predictions from the application of the model during stabilization seem to be more precise at high-temperature stabilization stages. It was shown that mechanical properties could be enhanced preferably by including a treatment step below 200oC, before the initiation of cyclization reactions. Further confirmation was provided via Raman spectroscopy, which demonstrated that graphitic like planes are formed upon stabilization above 200oC, and thus multistage stabilization is required to optimize synthesis of carbon fibers. Optical Microscopy proved that isothermal stabilization treatment did not severy alter the cross section geometry of PAN fiber monofilaments.

ACS Style

George Konstantopoulos; Spyros Soulis; Dimitrios Dragatogiannis; Costas Charitidis. Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization. 2020, 1 .

AMA Style

George Konstantopoulos, Spyros Soulis, Dimitrios Dragatogiannis, Costas Charitidis. Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization. . 2020; ():1.

Chicago/Turabian Style

George Konstantopoulos; Spyros Soulis; Dimitrios Dragatogiannis; Costas Charitidis. 2020. "Introduction of a Methodology to Enhance the Stabilization Process of PAN Fibers by Modeling and Advanced Characterization." , no. : 1.