Papers by Keyword: Graphene

Abstract: The advancement in digital 3D printing technology is further evolved with the development of new deposition materials. The materials for fused deposition modelling are successfully implemented in the field of medical and electronics engineering application for printing actual working products. The present paper deals with the effect of three different raster orientation angles and a 0.5 wt.% dope of graphene on the tensile strength of samples made of acrylonitrile butadiene styrene as per ASTM-D638 standard. It is interesting to observe that the samples prepared with a raster orientation of 0° degree with respect to the longitudinal axis showed highest tensile strength followed by 45° and 90°. The similar trend is also observed with the samples doped with 0.5 wt.% graphene although the tensile strength is observed to increase by 50% than that of the samples of plain ABS. In order to explore the effect of strain rate on tensile strength of plain and doped ABS specimens, the experiments were also performed at a cross head speed of 300mm/min and found that the strain rate increases the tensile strength by 2 to 3 times depending upon the raster orientation angle during fabrication of the samples.

Abstract: The manuscript investigates the leaf-shaped nanostrip-fed graphene plasmonic nanopatch on a silicon dioxide surface for optical near-field applications. The dispersion properties of graphene and silicon dioxide are demonstrated through Drude and Lorentz modeling to examine the suitability of the materials for the plasmonic nano-antenna design. The nano-antenna parameters T_SUB (substrate thickness), W (width of the nanostrip feed line) and R_L (nano-antenna size) are adjusted to modify the plasmonic resonance frequency from 7.9 THz to 40.9 THz. The proposed leaf-shaped nanostrip-fed graphene plasmonic nanopatch exhibits a reflection of -43.27 dB at 36 THz with a gain of 8.19 dB at T_SUB =125 nm, W = 40 nm and R_L = 50 nm.

Abstract: Cassava starch bioplastics have been known well as an alternative plastic replacing conventional petrochemical plastics, which have difficulty degrading rapidly in the environment. Cassava peels as waste is a potential eco-friendly starch source for biodegradable plastic. This study investigated the effect of graphene as a nanofiller on the hydrophobic properties of cassava peel starch film. Bioplastic was synthesized using the melt blending method by adding graphene in various amounts, which were 3 wt%, 5 wt%, and 7 wt%. Graphene was found to be able to increase the contact angle of the films up to 93° with the addition of 5 wt%. Graphene also affects water absorption properties. These results indicate that the hydrophobic properties of cassava peel starch films could be modified by adding graphene nanofiller.

Abstract: For the purpose of synthesizing 2D-Material–Magnetic nanocomposites, several new modifications of existing 2D-materials synthesis methods by exfoliation and chemical synthesis from liquid charge are developed. Using them, graphene (G), graphene oxide (GO), reduced graphene oxide (rGO) and hexagonal boron nitride (h-BN) matrix magnetic nanocomposites for the first time are obtained by coating or intercalation their nanoparticles with ferromagnetic iron (Fe) or ferrimagnetic iron oxide – magnetite (Fe₃O₄). These materials are prospective for variety of high tech applications. In particular, h-BN–Fe₃O₄ composite nanoparticles can serve for neutron-capturing boron isotope ¹⁰B effective delivery agents in BNCT (Boron Neutron Capture Therapy) of cancer as they allow the controlling by an external magnetic field targeting to tumor tissue.

Abstract: Intensive global research is focused on advanced conductive materials to meet the electrical requirements of the telecommunication and power industry. The primary aim is to enhance electrical conductivity, resulting of improved current-carrying capacity and reduced energy loss during transmission. Copper and its composites are vital for power transmission and telecommunications due to their electrical, thermal, and mechanical qualities. However, current methods have drawbacks, such as compromised conductivity with alloying. Graphene, an extraordinary carbon allotrope with exceptional properties and high conductivity, offers promising opportunities for the development of superior materials; such as graphene-incorporated copper (GrCu). The incorporation of graphene into copper wire holds significant potential for various industries, including electronics, energy transmission, and telecommunications, where high conductivity and reliability are paramount. This study investigates GrCu characteristics through mixing graphene and copper, vacuum melting, fine copper wire drawing, and GrCu coaxial cable manufacturing. Graphene infusion enhances conductivity and mechanical properties, altering microstructure and inducing twin boundaries in copper grains. Graphene's disruption during wire drawing triggers this effect, elevating wire conductivity to 103.5% by IACS. GrCu coaxial cable demonstrates performance coherence with HFSS simulation up to 6 GHz. Graphene's inclusion offers tailored material properties. Ongoing research promises further optimization and advancement of graphene-copper composites, paving the way for novel technological progress.

Abstract: Coordination polymers, a broad class of porous hybrid materials resulting from the connection of metal ions with organic ligands, showcase enduring porosity, well-organised crystalline structures, and open metal active sites that augment their metal ions' redox activity. This investigation focuses on examining a nanocomposite composed of cobalt carbide/reduced graphene oxide (Co₃C/rGO) prepared through the copolymer method, serving as an electrode material for supercapacitor devices. The nanocomposite's structure and hollow cubic morphology were confirmed through X-ray diffraction, Raman spectroscopy, and field emission scanning electron microscopy (FESEM) analysis. Electrochemical properties were thoroughly assessed using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge in 6M KOH with a voltage window of 0 V to 0.5 V. The Co₃C/rGO electrode exhibited notable electrochemical performance, displaying a specific capacitance of 486.6 F g^-1 at 1 mV s^-1 and a low internal resistance of 0.58 Ω, surpassing existing literature due to its porous morphology. Additionally, to evaluate the nanocomposite's cycling stability, 5000 charge/discharge cycles were conducted, revealing a capacitive retention of 82% of its original capacitance after 5000 cycles. This underscores its excellent long-term durability as a high-performance material for supercapacitor applications.

Abstract: We report the fabrication of porous hydrophobic flat sheet membranes composed of polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP), which is incorporated with graphene (GNP) concentrations of (0.2, 0.5, and 0.8 wt.%) as the hydrophobic filler. FTIR, XRD, and SEM results were used to analyze the composites' functional groups, crystallinity and surface morphology. The water contact angles were 116 ±1.2°; 120 ±0.9°; 126 ±0.7°; 130 ±0.6° for pristine, 0.2 wt%, 0.5 wt%, and 0.8 wt% of GNP membranes, respectively. Moreover, the graphene incorporation enhanced the fabricated polymer's ultimate tensile strength (UTS). The UTS was as follows 2.4±0.01, 5.43±0.02, 7.485±0.015 and 6±0.01MPa for pristine, 0.2 wt% GNP, 0.5 wt% GNP and 0.8 wt% GNP respectively. The highest UTS was (7.485 ±0.015 MPa) for the 0.5 wt% GNP. Graphene incorporation (0.5 wt%) enhanced the membranes’ porosity (78 ±1.9%). This study explored the effect of graphene to improve the flat sheet membranes' mechanical strength, hydrophobicity, and porosity, which can then be applied in desalination using membrane distillation to mitigate clean water shortages and crises.

Abstract: Flexible sensors and actuators have broad applications in the fields of wearable electronics for health, sports, functional textiles, robotics and cobot applications. Graphene-or graphite-based polymer nanocomposites are promising materials for the development of soft sensors and actuators. This study investigates strain sensing properties of silicon rubber with various graphene filler concentrations (8wt%-12wt%). Current-voltage characteristics have been measured under various strains. We obtain that the sensor’s electrical resistance, for a given voltage, can be approximated by a linear fit of the logarithmic resistance as function of the extension ratio of the sensor. The obtained mechanically induced logarithmic resistor behavior of the polymer nanocomposite is highly promising for the development of electronic sensing and control. Furthermore, thin film graphite layers were investigated on highly stretchable silicone membranes.

Abstract: The objective of the presented research is to improve the ballistic performance of para-aramid woven fabric by deposition of graphene coatings directly on woven textile substrates. The improvement of mechanical properties of the ballistic fabric is attributed to the formation of a highly ordered layered structure and the efficient load transfer between the fabric fibers and the graphene nanosheets. The results of deposition of layered graphene coatings on woven textiles are discussed here. The pristine graphite directly subjected to a solvent treatment in this work, which resulted in the production of exfoliated graphene sheets in the form of a dispersion that allow immediate utilization obtained dispersion for deposition on the para-aramid samples. In order to prepare the dispersion, graphite flakes were first dispersed into liquid media followed by graphite intercalation (division into microlayers) and nano-layers exfoliation. Dipolar aprotic organic solvent DMAc (N,N-Dimethylacetamide) and Cyrene (Dihydrolevoglucosenone) as a bio-based alternative for dipolar aprotic solvents were used as main components of liquid media. At the final stage, a stable dispersion of isolated flakes by using two types of liquid medium was obtained. To study the effects of dip coating and rolling parameters, six kinds of samples with different pull-out speeds and compression ratios were prepared, and their functional properties were measured and compared.

Abstract: Cracks could develop and propagate into the full depth of concrete, if disregarded. Repair of the concrete can be performed by filling the cracks with cement mortar as a repair material. With the advent of graphene, which is a nano-material that possesses remarkable properties, a graphene‑enhanced nano-cement composite can potentially be employed as a repair material for concrete. Effect of incorporating graphene nanoplatelets (GnP) into cement mortar at contents of 0.00, 0.02, 0.04, 0.06, 0.08 and 0.1 wt.% of GnP to total weight of cement on repair performance was investigated. Cylindrical concrete samples with a strength grade of 35 MPa were prepared and cured for 3, 7 and 28 days. The samples were cracked by subjecting them to compressive loading until failure. The mortar was then employed to repair the cracked samples. Compressive strengths of the sample before and after repair were recorded. Findings reveal that the graphene‑enhanced cement mortar was more aggressive in retaining as much compressive strength of the concrete as possible after crack and repair than plain cement mortar. However, concrete that was repaired with graphene-enhanced mortar was not able to retain the initial compressive strength. Nonetheless, the GnP content of 0.02 wt.% resulted in the best repair performance.