Including Carbon Nanotubes Research Articles

Computational modeling of composite armour and effect of CNT inclusion using orthotropic material model

We report development of indigenous Material Point Method (MPM3D) and Smoothed Particle Hydrodynamics (SPH3D) codes for modeling and design of composite body armour. Typical armour consists of a ceramic backed by a polymer matrix composite. The ceramic plate contributes to blunting of bullet nose, its erosion and reduction in speed. The polymer matrix with high tensile strength arrests the bullet. Mie-Gruneisen EOS, Johnson-Cook strength and failure models were used for projectile. Johnson-Holmquist (JH2) model was used for ceramics. An orthotropic model which accounts for different compression and tensile properties in through-thickness and in-plane directions was implemented and used for Ultrahigh Molecular Weight Polyethylene (henceforth termed as ‘PE’). The codes were validated against published results for impact onto PE targets. Then the codes were used to simulate various published experiments (of coauthors) on ceramic/PE composite targets performed according to NIJ standards. Back Face deformation (BFS) is measured. In all cases, the projectiles do not penetrate through the armour panels, consistent with experiments. Typically, the SPH and MPM codes compute BFS values which only deviate within 10–20 % of measured values. The simulation results are also compared with the commercial FEM code simulations. Experiments and simulations were carried out for PE reinforced with Carbon Nanotube (CNT) inclusions. The mechanical moduli and other strength parameters of PE are adjusted to account for the increase in flexural strength due to inclusion of CNT. The CNT inclusion greatly reduces the BFS. The simulations results qualitatively follow these trends.

Tubular nanomaterials for bone tissue engineering.

Nanomaterial composition, morphology, and mechanical performance are critical parameters for tissue engineering. Within this rapidly expanding space, tubular nanomaterials (TNs), including carbon nanotubes (CNTs), titanium oxide nanotubes (TNTs), halloysite nanotubes (HNTs), silica nanotubes (SiNTs), and hydroxyapatite nanotubes (HANTs) have shown significant potential across a broad range of applications due to their high surface area, versatile surface chemistry, well-defined mechanical properties, excellent biocompatibility, and monodispersity. These include drug delivery vectors, imaging contrast agents, and scaffolds for bone tissue engineering. This review is centered on the recent developments in TN-based biomaterials for structural tissue engineering, with a strong focus on bone tissue regeneration. It includes a detailed literature review on TN-based orthopedic coatings for metallic implants and composite scaffolds to enhance in vivo bone regeneration.

Non-enzymatic electrochemical sensors based on nanomaterials for detection of organophosphorus pesticide residues

Non-enzymatic nanocomposites and their modified electrodes, including carbon nanotubes, graphene, metal nanoparticles, metal oxides, conductive polymers, MOFs and derivatives, molecularly imprinted polymers are discussed in the rapid electrochemical sensing of OPPs.

Carbon-Based Stimuli-Responsive Nanomaterials: Classification and Application.

Carbon-based nanomaterials, including carbon nanotubes, carbon nanospheres, and carbon nanofibers, are becoming a research hotspot due to their unique structure and good mechanical, thermal, electrical, optical, and chemical properties. With the development of material synthesis technology, they can be functionalized and used in various fields such as energy, environment, and biomedicine. In particular, stimuli-responsive carbon-based nanomaterials have stood out in recent years because of their smart behavior. Researchers have applied carbon-based nanomaterials to different disease treatments based on their stimulus-response properties. In this paper, based on stimuli-responsive carbon-based nanomaterials' morphology, we categorize them into carbon nanotubes, carbon nanospheres, and carbon nanofibers according to their morphology. Then, their applications in probes, bioimaging, tumor therapy, and other fields are discussed. Finally, we address the advantages and disadvantages of carbon-based stimuli-responsive nanomaterials and discuss their future perspective.

Styrene–butadiene–styrene-based stretchable electrospun nanofibers by carbon nanotube inclusion

The state-of-the-art organic composite nanofibers have advantages due to their low cost, mechanical flexibility, light weight and electrical conductivity. Crystalline-to-amorphous transition and carbon-oxygen interactions are observed with addition of carbon nanotubes.

Selective heterogeneous capture and release of actinides using carborane-functionalized electrodes.

We report the heterogenization of molecular, electrochemically switchable ortho-substituted carboranes (POCb, POCb-Pyr) for selective metal capture. Films of POCb and POCb-Pyr on glassy carbon and carbon fiber (CF) electrodes demonstrated heterogeneous electrochemical behaviour that was enhanced by the inclusion of single-walled carbon nanotubes (CNTs). Galvanostatically charged CF|CNT|POCb and CF|CNT|POCb-Pyr electrodes selectively captured and released actinides (Th4+, UO22+) from mixed solutions containing alkali (Cs+), lanthanide (Nd3+, Sm3+) and actinide (Th4+, UO22+) metal ions.

HEAT-TRANSFER ENHANCEMENT OF MONO ETHYLENE GLYCOL-WATER-BASED SOLAR THERMIC FLUIDS DISPERSED WITH MULTIWALLED CARBON NANOTUBES IN A COILED TUBE HEAT EXCHANGER

The current research focuses on how the inclusion of multiwalled carbon nanotubes (MWCNTs) in mono ethylene glycol-water mixtures affects thermal conductivity, heat transfer, and dynamic viscosity for solar thermal applications. To achieve high stability in mono ethylene glycol-water mixtures, MWCNTs were oxidized and then dispersed at concentrations of 0.5, 0.25, and 0.125 wt.%. Zeta potential analysis was used to track the stability of the nanofluids over a two-month period. With the dispersion of MWCNTs in the base fluids, there is a remarkable increase in thermal conductivity from 15 to 24%. The dynamic viscosity variation is found to be minimal at high temperatures. Heat-transfer studies conducted on a specially designed test rig consisting of a coiled heat exchanger show that ethylene glycol-water mixtures dispersed with MWCNTs exhibit excellent performance under laminar conditions. Correlations for thermal conductivity, dynamic viscosity, and Nusselt number were obtained for all temperature conditions, mass fractions, and percentages of ethylene glycol. In the case of 100% mono ethylene glycol and mono ethylene glycol-water mixtures (90:10 and 80:20) as base fluids, the increase in heat-transfer coefficients of the corresponding nanofluids is up to 30, 26, and 25%, respectively.

Thermoelectric performance of Fe2ALV/CNT-based alloys

Heusler-type Fe2AlVxTi1-x alloys offer an alternative solution for the generation of thermoelectric power near room temperature. In the current research, thermoelectric properties of the p-type Fe2AlV0.9Ti0.1 and Fe2AlV0.9Ti0.1/CNT alloys, prepared by SPS, were studied. Carbon nanotubes (CNT) were used as dopants to improve the seebeck coefficient and electrical conductivity. Upon doping with CNT, the thermal conductivity was significantly reduced, meanwhile, the value of the power factor increased from 0.45 to 1.55 mW/mK2 at around 330 K. The effect of CNT inclusions on the thermoelectric parameters of Fe2AlVxTi 1-x compounds was systematically studied. When compared to Fe2AlV0.9Ti0.1, which had a figure of merit of just 0.02 at 330 K, the CNT-containing samples showed a significantly improved figure of merit up to 0.07. We offer a novel technique to improve the performance of Fe2AlV alloys.

Experimental study on the thermal properties of a novel ultra-high performance concrete reinforced with multi-scale fibers at elevated temperatures

The fire resistance of a novel ultra-high performance concrete is critical to its application, while the evolution of its thermal properties with temperature plays a key role in its fire resistance. Therefore, this study presents an experimental investigation of the thermal performance of newly developed ultra-high performance concrete reinforced by cenosphere and multi-scale fibers (MSFUHPC) including carbon nanotubes, calcium sulfate whiskers, carbon fibers, steel fibers, and polyethylene fibers under high temperatures ranging from 25 °C to 800 °C. Meanwhile, scanning electron microscope, thermogravimetry analysis, and mercury intrusion porosimetry tests are also conducted to study the thermal effect on the microstructure. Accordingly, the effect of multi-scale fibers and cenospheres on the thermal conductivity, volumetric specific heat, and thermal expansion of MSFUHPC are discussed. The results show that adding carbon nanotubes, carbon fibers, and hybrid fibers (steel fibers and polyethylene fibers) can increase thermal conductivity, and adding calcium sulfate whiskers and cenospheres exhibits an inverse effect at ambient temperature. In addition, the thermal expansion can be enlarged by incorporating carbon nanotubes or steel fibers and polyethylene fibers and restrained by adding carbon fibers. The influence of calcium sulfate whiskers and cenospheres on thermal expansion depends on their content. At high temperatures, the thermal conductivity shows an overall decreasing trend and the thermal conductivity of MSFUHPC is higher than that of its matrix and traditional UHPC, HPC, and NSC due to the reduction in the generation and propagation of cracks. By contrast, the volumetric specific heat shows an increasing trend with temperature. Besides, the thermal expansion of MSFUHPC is lower than that of UHPC, HPC, and NSC. The formulas of thermal parameters are fitted based on experimental data by considering the multi-scale fibers and temperatures, which can be used as input parameters for the numerical simulation of MSFUHPC structure under fire.

Carbon-based composites for removal of pharmaceutical components from water

Carbon-based materials. including carbon nanotubes, graphene, and activated carbon, are among the most effective materials for pharmaceutical components removal from water. Despite the severe effect of pharmaceutical micropollutants in the aquatic environments and the effectiveness of carbon-based composites for water treatment, only a few studies has reviewed carbon-based materials for the removal of pharmaceutical components. Carbon-based materials with special properties like tunable surface functions, abundant pore structure, and high specific surface are used in different water treatment mechanisms such as adsorption and advanced oxidation processes. Graphene, activated carbon, and carbon nanotubes have been widely studied for pharmaceutical components removal. Herein, we have introduced carbon-based materials and reviewed recent studies on their properties, application in water treatment, and possible mechanism for removal of pharmaceutical components from aquatic environments.

Carbon nanotube-adsorptive dynamic membrane (CNT-ADM) for water purification

Membrane technology plays an important role in water purification, but there are some significant challenges such as membrane fouling and deep purification efficiency. The work proposes a carbon nanotube-adsorptive dynamic membrane (CNT-ADM), including carbon nanotube (CNT) and membrane module, to solve these problems with low operating cost and high removal efficiency. Above all, on the basis of physical adsorption and membrane separation, a CNT-ADM was prepared by applying “forward filtration” of a CNT solution on an ultrafiltration membrane surface. Then, the effects of preparation time, CNT loading amount, transmembrane pressure (TMP) and shear stress on the morphology and permeability were analyzed to evaluate the preparation performance. Pore blocking models were utilized to explain the influence of CNT loading amount on membrane fouling mechanism. The best optimized condition for CNT-ADM preparation was: agitation speed of 50 rpm, TMP of 1 bar, CNT loading amount of 55 g/m2 and preparation time of 10 min. Furthermore, the optimized CNT-ADM was employed to treat the micro-polluted water. The effects of treatment condition on the micropollutant removal rate and flux were investigated with various shear stresses, TMPs, the amounts of micropollutant and CNT. Compared with the new membrane (below 10 %), CNT-ADM displayed a significant improvement for the micropollutant removal (above 95 % for three cycles), due to the synergy of membrane separation (sustaining CNT layer, separating micropollutant and increasing adsorption time) and adsorption removal (forming CNT layer and adsorbing micropollutant). On the other hand, the adsorption behavior also could effectively reduce the direct contact between membrane and micropollutant, then decreasing membrane fouling. Afterwards, the backwash cleaning was also successfully applied to alter the adsorption saturated CNT and generate the new CNT layer. In final, the implications for CNT-ADM application were discussed. Overall, CNT-ADM exhibits the desirable micropollutant removal and strong anti-fouling capacity, and has a great potential application in the sustainable water purification.

Development of a Carbon‐Based Flexible Strain Sensor for Diverse Human Motion Monitoring

The rapid development of flexible electronics greatly promotes personalized health monitoring and thereupon spawns diverse wearable electronic devices. As a key functional component of flexible electronics, flexible strain sensor receives tremendous research effort, and is widely applied to various areas such as electronic skin, human–machine interaction, and structural health monitoring. Carbon‐based materials including carbon nanotubes (CNTs), carbon black, and graphene are employed as functional materials in this paper to be mixed with the elastic polydimethylsiloxane (PDMS) matrix via the solution blending method. A bridge‐island structure is designed due to its unique structure and dispersion ability, enabling the derived sensor with both good stretchability of 100% and sensitivity of 8.99. The results offer a potential strategy for addressing the difficulties of sensitivity‐stretchability tradeoff originating from the flexible strain sensors prepared with single carbon‐based filler material and other similar strain sensors. Moreover, the realization of an intercommunication system between the flexible strain sensor and a mobile phone via NRF52805 Bluetooth communication chips can monitor various body motions in real time, demonstrating a promising prospect for building remote health monitoring and management systems.

Investigation of Field Emission Properties of Multi-Emitter Carbon Nanotube Cathodes

Currently, scientists are actively studying the properties of cathodes based on various carbon materials, including carbon nanotubes. The purpose of this work is the possibility of using multi-emitter carbon nanotube cathodes for the development of field cathodes. A study was made of the field emission properties of multi-emitter cathodes based on filaments of multi-walled carbon nanotubes. For the experiments, a structure was assembled from a plurality of cathodes placed on a common base. As a result, the hypothesis of additivity of currents at low voltage was confirmed.

A Review on Nanotechnology in Cancer Diagnosis and Therapy: it’s Application

Cancer is a leading cause of death and poor quality of life globally. Even though several strategies are devised to reduce deaths, reduce chronic pain and improve the quality of life, there remains a shortfall in the adequacies of these cancer therapies. Among the cardinal steps towards ensuring optimal cancer treatment are early detection of cancer cells and drug application with high specificity to reduce toxicities. Due to increased systemic toxicities and refractoriness with conventional cancer diagnostic and therapeutic tools, other strategies including nanotechnology are being employed to improve diagnosis and mitigate disease severity. Over the years, immunotherapeutic agents based on nanotechnology have been used for several cancer types to reduce the invasiveness of cancerous cells while sparing healthy cells at the target site. Nanomaterials including carbon nanotubes, polymeric micelles and liposomes have been used in cancer drug design where they have shown considerable pharmacokinetic and pharmacodynamic benefits in cancer diagnosis and treatment. In this review, we outline the commonly used nanomaterials which are employed in cancer diagnosis and therapy. We have highlighted the suitability of these nanomaterials for cancer management based on their physicochemical and biological properties. We further reviewed the challenges that are associated with the various nanomaterials which limit their uses and hamper their translatability into the clinical setting in certain cancer types. Keywords: Nanomaterials, Nanotechnology, Cancer, Diagnosis, Treatment.

Electrospun nanofiber mats as sorbents for polar emerging organic contaminants: Demonstrating tailorable material performance for uptake of neonicotinoid insecticides from water

The number and diversity of chemical contaminants in aquatic environments require versatile technologies for their removal. Here we fabricated various electrospun nanofiber mats (ENMs) and tested their ability to sorb six neonicotinoid insecticides, a model family of small, polar contaminants. ENM formulations were polyacrylonitrile (PAN) or carbon nanofibers (CNF; carbonized from PAN), with additives including carbon nanotubes (CNTs; with and without surface carboxyl groups), the cationic surfactant tetrabutyl ammonium bromide (TBAB), and/or phthalic acid (PTA; a CNF porogen). While sorption on pure PAN ENMs was low [equilibrium partition coefficients (KENM-W) from 0.9 to 1.2 log units (L/kg)], inclusion of CNTs and/or TBAB generally increased uptake in an additive fashion, with carboxylated CNT composites outperforming non-functionalized CNT analogs. CNF ENMs exhibited as much as a tenfold increase relative to PAN for neonicotinoid sorption, which increased with carbonization temperature. Ultimately, the optimal ENM (CNFs with carboxylated-CNTs, PTA, and carbonized at 800 °C) exhibited relatively fast uptake (equilibrium < 1 day without mixing) and surface-area-normalized capacities comparable to other carbonaceous sorbents (e.g., activated carbon). Collectively, this work demonstrates the versatility of electrospinning to produce novel sorbents specifically designed to target emerging chemical classes for applications including water treatment and passive sampling.

Synthesis and study of electrochemical properties of Ni-Co-V@PrGO to enhance hydrogen evolution reaction

Hydrogen evolution reaction (HER) is kinetically slow as a necessary half-reaction in water-splitting. It requires high-efficiency electrocatalysts to reduce the overpotential and improve energy conversion efficiency. Transition-metal electrode materials with high stability and efficiency have become the frontiers of energy conversion and storage fields. The present work involves the investigation of transition metals as electrocatalysts for HER. On the other hand, various carbon nanomaterials, including carbon nanotubes, activated carbon, and graphene for high-performance electrocatalysts, have been successfully shown. Still, their performances must be improved (using phosphorus-doped graphene) for wider and more challenging applications. The Ni-Co-V@PrGO was synthesized through a simple method with an amorphous structure that enhanced catalytic activity toward hydrogen evolution reaction with a Tafel slope of 80 and 58 mV dec−1 (counter electrode: Pt) and 85 and 118 mV dec−1 (counter electrode: graphite) in alkaline and acidic media, respectively. Hereupon this research presents a simple and efficient high-performance electrocatalyst for HER.

Polyacrylonitrile‐based electrospun nanofibers – A critical review

AbstractThis review is based on the fundamental aspects and applications of polyacrylonitrile (PAN)‐based electrospun composite nanofibers. Various electrospinning techniques have been discussed here. polyacrylonitrile is an acrylic polymer of commercial significance that has superior thermal, mechanical, electrical, and chemical properties. The integration of polyacrylonitrile nanofibers with nanoparticles including carbon nanotubes, graphene nanosheets, graphene oxide, metal oxides, and their combinations has greatly improved the physicochemical properties of the polyacrylonitrile electrospun nanofibers. The enhanced features of polyacrylonitrile nanofibers have resulted from interfacial bonding of nitrile groups with the nanofiller used, chemical compositions, hydrophobicity, porosity, and wettability of these nanofibers. This article fundamentally features a few key possibilities of polyacrylonitrile‐based electrospun composite nanofibers and their applications. A special focus has been made on polyacrylonitrile‐based inorganic nanoparticles, graphene nanosheets, graphene oxide, and carbon nanotubes embedded electrospun nanofibers, for their potential applications in supercapacitors, high power batteries, filtration membranes, electromagnetic interference shielding, and strain sensors. Achieving low cost, high selectivity, excellent recyclability, and high absorption capability are the major challenges for electrospun nanofiber fabrications. These electrospun nanofibers require extensive research in the future to advance the technologies to bring them to the commercial market.

Investigation into the Size Distribution of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;- ZnO Nanoparticles Dispersed in DI Water and Following the Impact of CNTs on the Stability, Heat Transfer, and Electricity Transfer of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;- ZnO-CNT Hybrid Nanofluid

The stability of dispersed nanoparticles in the base fluid has always been one of the most important challenges in using nanofluids as a coolant in heat transfer applications in different industries such as modern electronic equipment, heat exchangers, solar technologies, etc. In the present study, the dynamic light scattering (DLS) method is used to obtain the particle size distribution of Al2O3-ZnO dispersed in DI water. After adjusting the optical arrangement and designing the DLS setup, the correlation curves are plotted by analyzing the detected signals of the experiments. Then, a decay rate is derived by fitting an exponential function to the correlation curve to get the particle size distribution by using the Stoke-Einstein equation. In order to investigate the stability of Al2O3-ZnO water-based nanofluid, the particle size distribution profiles are studied several times. In addition, the stability of Al2O3-ZnO-CNT hybrid nanofluid is followed by absorbance measurements using a UV-Vis spectrophotometer. Moreover, the thermal conductivity coefficient and electrical conductivity of the Al2O3-ZnO hybrid nanofluid with and without CNT particles are determined by utilizing KD2 Pro and PCT-407 devices, respectively. The results showed that the peak in the particle size distribution curve for Al2O3-ZnO hybrid nanofluid shifted from 476 nm to 128 nm after 5 days. Furthermore, the inclusion of carbon nanotubes increased the stability of zinc oxide particles in the nanofluid. In addition, by adding carbon nanotubes in a ratio of 1:1:0.5 to Al2O3-ZnO nanofluid and forming 0.05 wt.% hybrid nanofluid, the thermal conductivity coefficient was enhanced by 30% in comparison with deionized water, while a 0.05 wt.% hybrid nanofluid without CNT particles improved the thermal conductivity by 19%. Although the electrical conductivity increased by adding nanoparticles to the base fluid, it didn’t change significantly for nanofluids containing CNTs compared to nanofluids without CNT particles.

A comparative study of GNPs and MWCNTs additives on dispersion behavior and strength characteristics of the adhesively bonded joints

In this research, the effects of graphene nanoplatelets (GNPs) and multi-walled carbon nanotubes (MWCNTs) inclusion at various weight fractions (0.25, 0.5, 0.75, and 1 wt%) on the dispersion behavior and strength characteristics of adhesively bonded joints were experimentally investigated and compared. For uniform dispersion of GNPs and MWCNTs across adhesive, an extensive solution mixing technique was carefully carried out. Two types of lap joints, that is, single lap joint (SLJ) and double strap joint (DSJ) were prepared using the neat and modified adhesive. The joints were fabricated using Al 5083 as adherends. A comparison of the strength properties was made after tensile testing of the lap joints. A substantial increase in the strength properties was observed with the added GNPs and MWCNTs. However, the strength response depicted by MWCNTs was superior to GNPs. A maximum improvement of 60% and 31% in lap shear strength was observed for SLJ and DSJ, respectively. This improved response was depicted at 1 wt% of MWCNTs addition in the adhesive. Fourier-transform infrared spectroscopy (FTIR) and ultraviolet–visible spectroscopy (UV–Vis-Nir) were utilized for chemical and dispersion analysis. Digital and scanning electron microscopy techniques were utilized in close examination of the fracture surfaces at high magnifications. Finally, a comprehensive discussion on the difference in strengthening mechanism between the two nanofillers was critically discussed.

Evident improvement in burning anti-dripping performance, ductility and electrical conductivity of PLA/PVDF/PMMA ternary blend-based nanocomposites with additions of carbon nanotubes and organoclay

In this study, carbon nanotubes (CNTs) and organoclay (30B) were introduced into poly(lactic acid) (PLA)/poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) (70/30/30) ternary blend, with PMMA acting as a compatibilizer for the PLA and PVDF phases. Morphological results indicated that PMMA tended to entangle more with PVDF than with PLA, and thus formed a pseudo co-continuous PLA(rich)-PVDF(rich) phase morphology in the blend. The added CNTs and 30B clay were mainly distributed in the PVDF(rich) phase and PLA(rich) phase, respectively, to achieve nanocomposites. The co-continuous bi-phasic morphology was more evident in the composites than in the parent blend. Thermal property results revealed the nucleation effect of CNTs and 30B on the crystallization of PLA and PVDF; the presence of PMMA obviously retarded the crystal growth of PVDF due to their miscibility. Adding CNTs or hybrid CNT/30B evidently improved the anti-dripping performance of the ternary blend in burning tests. The ductility (elongation at break) of PLA/PVDF blend drastically improved with PMMA inclusion, and the composites also showed excellent ductility. The ductility of PLA and PLA/PVDF blend increased by up to 18.9 and 14.4 times, respectively, after forming the 3-phr hybrid CNT/30B-loaded composite. Rigidity of the ternary blend increased after forming the composites; flexural modulus increased by 16% with 3 phr CNT inclusion. Rheological properties revealed the (pseudo)network structure development in the composites. The electrical resistivity of the ternary blend reduced by 11 orders at 2 phr CNT loading (double percolation achieved), and the percolation threshold was at 0.5 phr CNT loading.