Article
Chemistry, Physical
Jiheng Ding, Hongran Zhao, Haibin Yu
Summary: The study developed a method to synthesize edge-selective sulfonic-acid functionalized graphene (ESfG) with high yield, which showed a thermal conductivity of 3.11 W/mK in water-based nanofluids, the highest recorded to date. The ESfG aqueous nanofluids exhibited much higher heat transfer capability compared to water and also demonstrated high storage stability, making it a promising candidate for high-performance thermally conductive nanofluids in efficient thermal management applications.
Article
Nanoscience & Nanotechnology
Lucas Luciano Cullari, Tom Masiach, Sivan Peretz Damari, Shani Ligati, Istvan Furo, Oren Regev
Summary: Adding fibrous clay mineral, sepiolite, in water can effectively enhance the dispersion concentration of graphene, maintaining high lateral size dispersion. This method can be applied as cooling liquids for thermal management solutions, resulting in a 26% enhancement in thermal conductivity.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Soha Aldroubi, Eric Anglaret, Ibrahim Bou Malham, Peter Hesemann, Nicolas Brun, Ahmad Mehdi
Summary: The use of aromatic imidazolium-based ionic liquids has been demonstrated as an effective method for the sonochemical exfoliation of graphite, resulting in stable graphene dispersions. Specifically, 1-(naphthylmethyl)-3-benzylimidazolium bis(trifluoromethanesulfonyl)imide was found to produce solid dispersions of few layer graphene sheets with long-term stability and high concentration at room temperature.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Physics, Applied
Zahra Barani, Kamil Stelmaszczyk, Fariborz Kargar, Yevhen Yashchyshyn, Grzegorz Cywinski, Sergey Rumyantsev, Alexander A. Balandin
Summary: The interaction of terahertz electromagnetic radiation with dilute graphene-epoxy composites was studied experimentally, showing unexpectedly high shielding effectiveness achieved mainly through absorption. The shielding effectiveness increases with frequency, suggesting the potential for practical applications with thin-film or spray coatings of these composites.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Kai Ling Ng, Barbara M. Maciejewska, Ling Qin, Colin Johnston, Jesus Barrio, Maria -Magdalena Titirici, Iakovos Tzanakis, Dmitry G. Eskin, Kyriakos Porfyrakis, Jiawei Mi, Nicole Grobert
Summary: Achieving sustainable and low-cost production of high-quality graphene is a challenge for large-scale utilization of 2D materials. This study demonstrates that isopropanol can exfoliate graphite as efficiently as NMP, providing potential for sustainable graphene manufacturing.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Wen-hua Xu, Yue He, Heng Xie, Sen Qin, Ling-cao Tan, Ting Wu, Jin-ping Qu
Summary: The newly developed one-step melt mixing strategy utilizes the synergy of steam explosion and alternating convergent-divergent flow to rapidly produce high-quality graphene nanosheets from expanded graphite, which are then dispersed in the melt within a short time frame. The produced nanosheets improve the crystallinity of HDPE and form a thermally-conductive network, enabling applications in solar-to-thermal conversion and heat dissipation.
Article
Chemistry, Physical
M. L. Pereira Junior, W. F. da Cunha, W. F. Giozza, R. T. de Sousa Junior, L. A. Ribeiro Junior
Summary: This article introduces a new 2D carbon material called Irida-Graphene (IG), which was computationally designed using density functional theory calculations and reactive molecular dynamics simulations. The results show that IG exhibits good mechanical and thermal stabilities, with an estimated elastic modulus of approximately 396 GPa. It is a metallic non-magnetic material with a Dirac cone in the center of the band. IG has intense optical activity in the infrared and violet regions, making it a potential violet collector for photon energies of about 3.0 eV.
Article
Nanoscience & Nanotechnology
Ali Motaee, Soheila Javadian, Mahnaz Khosravian
Summary: The study investigates the relationship between adsorption energy and dispersing ability of surfactants in surfactant-assisted liquid-phase exfoliation of graphite, showing that adsorption energy correlates with tail length, but that the most effective surfactant can vary depending on concentration levels and molecular size.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Physical
Barbara Abreu, Jorge Montero, Matat Buzaglo, Oren Regev, Eduardo F. Marques
Summary: The study focused on separating and dispersing multiwalled carbon nanotubes and graphene nanoplatelets using controlled processing conditions and different types of surfactants. Bell-shaped dispersibility curves were obtained, revealing common fundamental features in the dispersing process of 1D and 2D nanocarbons. Despite differences in dispersal yields, a master curve for dispersibility suggests underlying similarities in the dispersing mechanisms.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Physical
Linfeng Yu, Yuqi Zhan, Donghai Wei, Chen Shen, Hongbin Zhang, Zhenzhen Qin, Guangzhao Qin
Summary: This article introduces a multifunctional 2D graphene-like boron nitride material (g-B3N5) with a buckling structure, which has been proven to be stable in terms of mechanical, thermal, dynamic, and energetic behaviors. Furthermore, the mechanical, electronic, thermal, and optical properties of the material have been systematically explored, showing excellent performances such as negative Poisson's ratio, ultra-wide band gap, low thermal conductivity, and highly tunable photon absorption peak by strain engineering.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Jiabin Hong, Shihao Fan, Yonglin Wu, Chunxiang Wang, Zhifeng Li, Jun Chen, Shengwen Zhong
Summary: The xylitol-assisted mechanochemical exfoliation method provides a new approach for large-scale preparation of graphene nanosheets with excellent electrochemical performance as the negative electrode material in lithium-ion batteries.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Chemistry, Analytical
Dusan Losic, Farzaneh Farivar, Pei Lay Yap, Afshin Karami
Summary: Counterfeits in the supply chain of high-value advanced materials like graphene have become a concern, with recent studies showing a large percentage of manufactured graphene materials not actually being graphene. Traditional characterization methods have limitations, making it crucial to use reliable methods like thermogravimetric analysis (TGA) to detect unwanted additives. Research demonstrates the superior performance of TGA in successfully identifying carbon additives mixed with graphene materials.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Rahul Navik, Huijun Tan, Zhiyuan Liu, Qixuan Xiang, Yaping Zhao
Summary: A poly-propylene/few-layer graphene (PP/FLG) composite with enhanced interfacial adhesion was successfully fabricated using a combination of planetary ball milling and supercritical CO2 (scCO2). The composite exhibited significantly improved thermal and electrical conductivity as well as mechanical performance. The successful fabrication process holds great potential for the development of functional polymer-graphene composites for next-generation electronic devices.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Zheng Zhu, Xuran Xu, Yihang Yao, Cong Guo, Jingyu Chen, Yongzheng Zhang, Kai Wu
Summary: Gallium-based liquid metal was found to reduce interlayer interactions in boron nitride nanosheets (BNNSs), leading to high exfoliation efficiency. The exfoliated BNNSs still maintained electrical insulating properties, showing potential in thermally conductive yet electrically insulating applications.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Composites
Haipeng Dong, Minghui Liu, Xianlei Chen, Guofang Han, Liang Li, Fangfang Lu, Baikang Zhu, Hengcong Tao
Summary: In this study, graphene was successfully exfoliated and dispersed in polypropylene matrix using in situ liquid-phase exfoliation method. By centrifuging the graphene under specific conditions and extruding at a specific temperature, the composite achieved significant improvement in mechanical properties with the addition of only 0.2 wt% graphene. The inclusion of graphene not only enhanced the yield strength, bending modulus, and impact strength of the composite, but also increased the thermal conductivity.
POLYMER COMPOSITES
(2022)
Article
Thermodynamics
T. Shockner, G. Ziskind
Summary: Thermal energy storage is crucial for the advancement of renewable energy. Close-contact melting in phase-change materials plays a significant role in speeding up the charging process. This study explores the melting behavior of PCM in a vertical cylindrical enclosure and demonstrates the importance of close-contact melting.
APPLIED THERMAL ENGINEERING
(2023)
Article
Construction & Building Technology
Amr Alatawna, Yarden Rahamim, Carina Hartig, Alva Peled, Oren Regev
Summary: Textile reinforced concrete (TRC) is a stronger, more flexible, and non-corrosive alternative to steel rebar reinforcement. It forms multiple thin cracks upon loading instead of wide cracks in rebar reinforcement. The self-healing of these cracks can be accelerated by modifying the concrete matrix and decorating the carbon-based textile.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Chemistry, Physical
Adi Lavi, Michael Pyrikov, Avia Ohayon-Lavi, Rafael Tadmor, Gal Shachar-Michaely, Yelena Leibovitch, Efrat Ruse, Leonid Vradman, Oren Regev
Summary: In this study, the exfoliation of graphite to graphene nanoplatelets (GnP) in a molten salt medium was investigated. The process yielded large-sized GnP with low defect density without the need for mechanical force. The effect of the surface tension of the molten salt on graphite exfoliation efficiency was examined, and it was found that the salt with the lowest surface tension (CsCl) facilitated total exfoliation of graphite to GnP.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Mechanics
S. D. Amar, A. Rashkovan, G. Ziskind
Summary: In this study, the flow field of a free-surface vortex in a rotating cylinder with a drain hole is investigated using numerical and analytical methods. The modified analytical model is capable of accurately predicting the free-surface profile for low rotation rates, while only numerical simulation can predict the relation between the flow field within the liquid and the free-surface profile for high rotation rates.
Article
Engineering, Manufacturing
Shani Ligati Schleifer, Oren Regev
Summary: The use of additive manufacturing (AM) enables the rapid creation of complex structures, including heat sinks and heat exchangers, for efficient heat dissipation. Researchers have developed a method using vat photopolymerization (VPP) and graphene-based thermally conductive filler to prepare heat sinks with high thermal conductivity (TC). By stabilizing graphene nanoplatelets (GNP) with a fiber-like clay filler, phase separation is prevented, allowing for a composite with a relatively high GNP concentration of 2.0 wt % and a 160% increase in TC compared to the pristine polymer. This printing technique also yields a material with anisotropic TC, with a cross-plane/in-plane (TC/TC=) ratio of 1.6, beneficial for thermal management systems.
ADDITIVE MANUFACTURING
(2023)
Article
Thermodynamics
Avia Ohayon-Lavi, Gal Shachar-Michaely, Elad Koronio, Yair Keller, Eilam Yalon, Gennady Ziskind, Oren Regev
Summary: This study proposes a novel conformal coating with enhanced thermal conductivity for effective heat dissipation from hot spots on printed circuit boards. By loading a polymer with graphene nano-platelets (GnP), a heat-dissipating composite with two orders of magnitude higher thermal conductivity (33 W/m K) is created. Experimental results show that the temperature of the component significantly decreases when the coating is applied, with a temperature drop of up to 35 degrees C under the given conditions. Numerical simulations provide further insights and confirm the experimental findings. The thin conformal coating can easily be used for thermal management in various applications in the electronic industry.
APPLIED THERMAL ENGINEERING
(2023)
Article
Chemistry, Physical
Gal Shachar-Michaely, Noam Lusthaus, Gennady Ziskind, Lev Vaikhanski, Yachin Cohen, Oren Regev
Summary: The aggressive miniaturization in the electronics industry calls for more efficient thermal management. This study enhanced thermal conductivity by using graphene nanoplatelets as a filler and controlled heat dissipation by compressing the composite. The research met diverse thermal management needs by achieving high thermal conductivity and controlling heat dissipation direction.
Article
Thermodynamics
Elad Koronio, Darin J. Sharar, Mark S. Spector, Oren Gal, Tomer Shockner, Oren Regev, Gennady Ziskind
Summary: This study experimentally and numerically investigated a PCM-based heat sink, and found that metallic PCM has higher thermal properties than organic paraffin, leading to more efficient heat absorption and reduced system peak temperatures.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Y. Soffer, Y. Aharon, G. Ziskind
Summary: This research focuses on characterizing the Onset of Nucleate Boiling (ONB) in an enclosed narrow gap system with a stationary liquid. Different heat transfer mechanisms are observed depending on the gap size, including convection, transition, and conduction. The onset of nucleate boiling is detected when the heat transfer coefficient behavior changes dramatically. An analytical model based on experimental values is developed to predict ONB heat flux with good agreement.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Multidisciplinary Sciences
Adi Lavi, Avia Ohayon-Lavi, Yelena Leibovitch, Shmuel Hayun, Efrat Ruse, Oren Regev
Summary: Renewable energy technologies rely on efficient thermal energy storage devices, which often use molten salts. However, the low thermal conductivity of these salts limits their storage kinetics. This study explores the use of partially exfoliated graphite to form graphene nanoplatelets in a molten salt matrix to enhance thermal conductivity. The resulting hybrid composite material shows a significant improvement in thermal conductivity compared to the pristine salt.
Article
Chemistry, Physical
Avia Ohayon-Lavi, Subish John, Adi Lavi, Yelena Leibovitch, Leonid Vradman, Efrat Ruse, Oren Regev
Summary: 2D materials are of interest in various applications such as energy conversion, storage, and sensing. These materials are prepared by bottom-up or top-down methods that are difficult to control and suffer from low yield. Synthesis in molten salt is suggested as an alternative in which the balance between exfoliation and solubility is explored.
Article
Chemistry, Physical
Yonatan Luzzatto, Amer Alatawna, Eli Peretz, Orit Mendelson, Svetlana Pevzner, Oren Regev
Summary: Hydrogen, a promising renewable energy source, poses challenges in industrial processes due to its ability to penetrate metals and cause embrittlement, leakage, and explosion risks. This study investigates the combined effect of a polymer liner loaded with graphene and unsaturated organic molecules in reducing hydrogen diffusion. The approach involves creating a hydrogen barrier using graphene nanoplatelets and chemically absorbing hydrogen using unsaturated organic molecules. The study finds that both graphene and unsaturated organic molecules significantly decrease hydrogen diffusion, and the presence of graphene allows hydrogen to migrate over its surface to reach the unsaturated molecules. Additionally, the study demonstrates that a polymer loaded with unsaturated organic molecules can serve as a visual hydrogen sensor. These findings provide important principles for designing functional materials for hydrogen detection, transportation, and storage.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Multidisciplinary Sciences
Adi Lavi, Avia Ohayon-Lavi, Yelena Leibovitch, Shmuel Hayun, Efrat Ruse, Oren Regev
Summary: This study explores the partial exfoliation of graphite to graphene nanoplatelets (GnP) in a molten salt matrix to enhance thermal conductivity and the efficiency of thermal energy storage devices.