Potential Of Carbon Nanotubes Research Articles

Recent Advances in Carbon Nanotube Technology: Bridging the Gap from Fundamental Science to Wide Applications

Carbon nanotubes, as carbon allotropes distinguished by their intricate structures and exceptional physicochemical properties, have demonstrated substantial progress in recent years across diverse domains, including energy production, chemical synthesis, and environmental preservation. They exhibit notable attributes such as high thermal stability, superior adsorption capacity, and a substantial specific surface area, rendering them superb catalyst supports. Particularly in electrochemical energy storage, CNTs are extensively employed in supercapacitor electrodes owing to their elevated electrical conductivity, mechanical robustness, and electrocatalytic prowess, which facilitate significant energy storage capabilities. Their intricate pore architecture and reactive sites make functionalized carbon nanotubes well suited for synthesizing composite materials with diverse components, which are ideal for sequestering carbon dioxide from both atmospheric and indoor environments. This review presents a comprehensive examination of carbon nanotube synthesis methodologies, encompassing chemical vapor deposition, arc discharge, and laser ablation, and evaluates their impacts on the structural and functional properties of carbon nanotubes. Furthermore, this article underscores the applications of carbon nanotubes in fields such as fuel cells, photocatalysis, ammonia synthesis, dry methane reforming, Fischer–Tropsch synthesis, and supercapacitors. Despite the considerable potential of carbon nanotubes, their manufacturing processes remain intricate and costly, impeding large-scale industrial production. This review concludes by addressing the challenges in fabricating carbon nanotube composites and outlining future development prospects.

Remarkable lubricity of CNTs microspheres as additives in oil lubricant for ceramic components

Severe wear was often caused by adhesive wear and tribo-chemical reaction for ceramic components. In view of this situation, potentials of carbon nanotubes (CNTs) used as oil additives were explored for lubrication of ceramic/steel tribo-components. Microscopic morphology and dispersion stability of the prepared CNTs were characterized. CNTs microspheres were formed and this might because of their aggregation that also lead to the weak dispersion stability. Additionally, nano-fluids containing various concentration of CNTs microspheres were prepared for exploring the optimum concentration, where their lubricating behavior for ceramic/steel tribo-components was investigated to determine the relation between CNTs microspheres and tribological properties. The results indicated that the optimum concentration was 0.2 wt%, where 53.1 % of friction reduction and 50.7 % of wear resistance were achieved at high contact stress of 1.35 GPa. The superior lubricity of CNTs microspheres might be attributed to their rolling movement and formation of protective film.

Quantitative analysis of the correlation between sp3 bonds and functional groups in covalently functionalized single-walled carbon nanotubes

The potential of carbon nanotube (CNT)-based applications in diverse scientific fields has been demonstrated by achieving precise control of their surfaces through chemical functionalization. However, the formation of fatal defects like sidewall cleavage is an increasingly important concern as it significantly degrades the performance of CNTs. The presence of these structural disruptions has been ascertained by transmission electron microscopy, but a comprehensive understanding of their surface remains unclear due to its highly localized observation. Here, we demonstrate a framework for quantitative evaluation of the relationship between sp3 bonds and functional groups on CNT surface by combining μ-Raman and energy dispersive X-ray spectroscopy in scanning electron microscope imaging techniques. Nonuniform features of the degree of functionalization in strongly oxidized two types of single-walled CNTs are appropriately visualized in both measurements, allowing a systematic assessment of the surface states. Quantitative analysis reveals that the nm-scale sidewall openness during the chemical process is adequately explained by introducing a variable θ defined as the ratio of the degree of functionalization/defect density. These findings can be widely utilized as a novel evaluation technique to control the reactivity in the surface functionalization of various carbon nanomaterials.

Stereoselective 1,2 migration of a boronate complex inside a nanoreactor: QM/MM study

In this study, we investigate the stereoselective 1,2 migration reaction inside a carbon nanotube (CNT) using a combined quantum mechanics/molecular mechanics (QM/MM) approach. The steric and electronic effects of the CNT are found to significantly influence the stabilization of the guest molecule, highlighting the importance of nanotube diameter. By adjusting the nanotube diameter, it becomes possible to control the stereoselectivity of the migration reaction. Nanoreactors, such as CNTs, have emerged as promising tools for manipulating chemical reactions due to their versatile properties. We explore the impact of the nanotube environment on the migration mechanism and discuss the role of non-covalent interactions, such as van der Waals forces, in promoting stability and selectivity. Our computational results demonstrate that the presence of the CNT affects the reaction kinetics, energy barriers, and overall energetic outcomes. The choice of nanotube diameter is crucial to achieve optimal confinement of the guest molecule while maintaining stabilizing interactions. This study provides valuable insights into the potential of carbon nanotubes as nanoreactors for controlling stereochemistry in organic reactions, offering opportunities for tailored reaction design and synthesis.

A Critical Review of Carbon Nanotube-Based Surface Coatings

The emergence of carbon nanotubes (CNT) has encouraged widespread interest among researchers with many pioneering applications achieved by exploiting the unique properties of carbon allotropes. This article is a general overview of the diversity of applications of CNT and their various forms, particularly, in the area of surface coatings. The different methods, which have been developed and practiced in the preparation, dispersion, functionalization, and metallization of CNT, are elucidated. The composite coatings have been prepared using electrochemical methods such as electroplating and electroless plating. The review presents the mechanical, electrochemical, corrosion, thermal, electrical conduction, tribological, biosensing, magnetic, and microwave absorbing properties of CNT-based composites. The incorporation of CNT substantially affects the coating performance, and the level of influence can be befittingly adjusted to suit the application needs. Various characterization studies have been conducted on these coatings, emphasizing their properties. The potential of CNT as a versatile material in catering to diverse industrial applications has placed the carbon allotrope among the elite group of materials, drawing the attention of researchers to widen their scope of utilization. The challenges, problems, and ways of the overcoming are also addressed in this review.

Effect of CNTs Additives on the Energy Balance of Carbon/Epoxy Nanocomposites during Dynamic Compression Test

Previous research has shown that nanocomposites show not only enhancements in mechanical properties (stiffness, fracture toughness) but also possess remarkable energy absorption characteristics. However, the potential of carbon nanotubes (CNTs) as nanofiller in reinforced epoxy composites like glass fiber-reinforced polymers (GFRP) or carbon fiber-reinforced polymers (CFRP) under dynamic testing is still underdeveloped. The goal of this study is to investigate the effect of integrating nanofillers such as CNTs into the epoxy matrix of carbon fiber reinforced polymer composites (CFRP) on their dynamic energy absorption potential under impact. An out-of-plane compressive test at high strain rates was performed using a Split Hopkinson Pressure Bar (SHPB), and the results were analyzed to study the effect of changing the concentration of CNTs on the energy absorption properties of the nanocomposites. A strong correlation between strain rates and CNT mass fractions was found out, showing that an increase in percentage of CNTs could enhance the dynamic properties and energy absorption capabilities of fiber-reinforced composites.

Influence of ball milling parameters on the dispersion characteristics and structural integrity of MWCNTs in nickel aluminide matrix powders

The novelty of incorporating carbon nanotubes (CNTs) in various matrices is becoming increasingly significant for the development of various composites to match the rising technological demands in industry. However, for the potentials of CNTs to be fully realized, the mandatory requirement to uniformly disperse them must be achieved. To effectively disperse these nanotubes in metallic matrices, ball milling has emerged as an effective method, but concerns still persist as to the ability of this method to achieve uniform dispersion without significant damage to the CNTs. In this work, multi-walled carbon nanotubes (MWCNTs) were dispersed in a nickel aluminide matrix via three different milling methods, using both low and high energy milling regimes. The admixed powders were characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry and transmission electron microscopy techniques. Results show that a two-stage milling, comprised of a 6-h low energy milling with a short-term follow-up of a low speed 2-h high energy milling achieved the best MWCNTs dispersion and retained their structural integrity.

Multifunctional Carbon Nanotubes Enhanced Structural Composites with Improved Toughness and Damage Monitoring

The potential of carbon nanotubes (CNT) as multifunctional filler in poly(epoxy)-based structural composites has been investigated. In a first step the reinforcement effect of CNT has been studied by tensile and three points bending tests, which evidenced significant improvements of stress and strain at break (respectively +17% and +30% for tensile tests on unidirectional carbon fibre-epoxy composites). Moreover, fracture experiments have also revealed a positive effect of CNT on the toughness (G1c) of carbon fibres-epoxy composites (+105% of improvement at the initial stage). In a second step, the health monitoring capability quantum resistive strain sensors (sQRS) made of CNT filled epoxy nanocomposite, incorporated in the core of glass fibres-epoxy composites has been studied. It was shown that during cyclic tensile tests, following the evolution of the relative resistance amplitude (Ar) of sQRS with strain gives a pertinent information on non-reversible phenomena such as plastic deformation and cracks’ development within the composite. In particular, the evolution of the sQRS sensitivity (gauge factor GF) under and over the elastic limit, allows to track damage accumulation throughout the composite. These results suggest a possible use of sQRS for the structural health monitoring (SHM) of composites in fields such as boating, wind energy, aeronautics and automotive.

Potential of Carbon Nanotubes in Enhance of Photocatalyst Activity

Potential of Carbon Nanotubes in Enhance of Photocatalyst Activity

A comparison of suspension versus air–liquid interface experiments to assess the (pro-)fibrotic potential of carbon nanotubes in vitro

A comparison of suspension versus air–liquid interface experiments to assess the (pro-)fibrotic potential of carbon nanotubes in vitro

Atomistic Model Analysis of Buckling Behavior of Compressed Carbon Nanotubes

We carried out the atomistic structural instability (ASI) analysis with an empirical interatomic potential for carbon nanotubes (CNTs) under axial compression with the aim to reveal the mechanism of buckling. We investigated how ‘latent’ instability modes develop until one of them is activated at the structural instability. For pristine single-walled carbon nanotubes (SWCNTs), Euler-type buckling was found in relatively thin nanotubes, while buckling modes corresponding to change in the cross-sectional shape (radial buckling) were found in thick nanotubes. The crossover between the Euler-type buckling and radial buckling modes was clearly seen in the ASI analysis. While the reduction of Hessian eigenvalues in the pristine nanotubes and nanotubes with a vacancy is nearly linear until instability, rapid decrease of eigenvalues just before instability was found in models with Stone-Wales defects. This is due to localization of instability mode vectors around the defects that tends to arise before structural instability.

Performance Comparison of Carbon Nanotubes with Copper and Aluminium as Winding Material in Transformer

Objectives: Transformers are used in almost every industry; therefore further improvement in their efficiency is always desirable. The objective of this work is to study the potential of Carbon Nanotubes to replace copper/aluminum in transformers. Methods/Analysis: In this work, FEM (Finite Element Method) technique based planar model of an aluminum-wound transformer is developed in FEMM software. The magnetic and steady state heat flow analysis of this transformer has been carried out. Then, the thermal and electrical properties of aluminum windings are replaced with that of new carbon based nanomaterial; Carbon Nanotubes (CNTs) and copper respectively to measure the effect on the performance of the transformer. Theoretical electrical conductivity of CNTs, which is much higher than that of macroscopic yarns till date, has been used. Findings: The comparison of maximum winding I2R losses and maximum winding temperature rise, when winding material is taken as aluminum, copper and CNT respectively, has been done. Also, weight of the conductor required has been compared. Maximum winding I2R losses and maximum winding temperature rise obtained in case of CNTs are lower than that in case of copper and aluminum. Weight of the conductor is also less than copper/aluminum. Application/Improvement: Previous work on use of CNT windings in transformer have demonstrated that it works in accordance with the classical theory of transformers. In this work, the effect on transformer winding losses and temperature rise has been analyzed when conventional winding materials are replaced by CNTs.

A study of the stability of aqueous suspensions of functionalized carbon nanotubes

The properties of aqueous suspensions of carbon nanotubes have been studied as depending on the conditions of their functionalization in a mixture of sulfuric and nitric acids. The elemental composition and contents of carboxyl, lactone, and hydroxyl groups in carbon nanotubes have been determined at different durations and temperatures of functionalization. The influence of functionalization conditions on the value of the electrokinetic potential of carbon nanotubes in aqueous suspensions and the nanotube solubility in water has been investigated. It has been found that the absolute value of the electrokinetic potential of nanotubes and their solubility in water increase with both the duration and temperature of functionalization due to a rise in the number of functional groups on their surface. The optimal regimes of functionalization of carbon nanotubes have been determined from the point of view of preserving their structure and stability in aqueous dispersions.

Bridged single-walled carbon nanotube-based atomic-scale mass sensors

The potentials of carbon nanotubes (CNTs) as mechanical resonators for atomic-scale mass sensing are presented. To this aim, a nonlocal continuum-based model is proposed to study the dynamic behavior of bridged single-walled carbon nanotube-based mass nanosensors. The carbon nanotube (CNT) is considered as an elastic Euler–Bernoulli beam with von Karman type geometric nonlinearity. Eringen’s nonlocal elastic field theory is utilized to model the interatomic long-range interactions within the structure of the CNT. This developed model accounts for the arbitrary position of the deposited atomic-mass. The natural frequencies and associated mode shapes are determined based on an eigenvalue problem analysis. An atom of xenon (Xe) is first considered as a specific case where the results show that the natural frequencies and mode shapes of the CNT are strongly dependent on the location of the deposited Xe and the nonlocal parameter of the CNT. It is also indicated that the first vibrational mode is the most sensitive when the mass is deposited at the middle of a single-walled carbon nanotube. However, when deposited in other locations, it is demonstrated that the second or third vibrational modes may be more sensitive. To investigate the sensitivity of bridged single-walled CNTs as mass sensors, different noble gases are considered, namely Xe, argon (Ar), and helium (He). It is shown that the sensitivity of the single-walled CNT to the Ar and He gases is much lower than the Xe gas due to the significant decrease in their masses. The derived model and performed analysis are so needed for mass sensing applications and particularly when the detected mass is randomly deposited.

Lentinan-Modified Carbon Nanotubes as an Antigen Delivery System Modulate Immune Response in Vitro and in Vivo

Adjuvants enhance immunogenicity and sustain long-term immune responses. As vital components of vaccines, efficient adjuvants are highly desirable. Recent evidence regarding the potential of carbon nanotubes (CNTs) to act as a support material has suggested that certain properties, such as their unique hollow structure, high specific surface area, and chemical stability, make CNTs desirable for a variety of antigen-delivery applications. Lentinan, a β-1,3-glucohexaose with β-1,6-branches that is extracted from the mushroom Lentinus edodes, is an effective immunostimulatory drug that has been clinically used in Japan and China, and recent studies have proved that specific beta-glucans can bind to various immune receptors. In this research, we covalently attached lentinan to multiwalled carbon nanotubes (MWCNTs) and tested their ability to enhance immune responses as a vaccine delivery system. In vitro study results showed that the nanotube constructs could rapidly enter dendritic cells and carry large amounts of antigen. Moreover, maturation markers were significantly upregulated versus the control. Thus, lentinan-modified multiwalled carbon nanotubes (L-MWCNTs) were regarded as an effective intracellular antigen depot and a catalyzer that could induce phenotypic and functional maturation of dendritic cells. Furthermore, compared with L-MWCNTs (35 μg/mL), a corresponding concentration of carboxylic carbon nanotubes (C-MWCNTs, 31.8 μg/mL) and an equivalent concentration of lentinan (3.2 μg/mL) did not remarkably influence the immune reaction in vitro or in vivo. Hence, we can hypothesize that the capability of L-MWCNTs was a consequence of the increased intracellular quantity of lentinan grafted onto the nanotubes. Overall, our studies demonstrated that L-MWCNTs significantly increased antigen accumulation in the cells and potentiated cellular and humoral immunity. In conclusion, L-MWCNTs constitute a potential vaccine delivery system to enhance immunogenicity for therapeutic purposes.

Nanovectorization of DNA Through Cells Using Protamine Complexation.

Carbon nanotubes (CNT) are currently used as a promising family of nanovectors able to deliver different types of therapeutic molecules. Several applications dealing with CNT used as drug nanocarriers have been developed since their ability to penetrate into the cells has been proved. CNT can thus load several active molecules to various cells. In this paper, we will use molecular dynamic simulation to describe theoretically the potential of CNT to transport and deliver DNA through the formation of protamine-DNA-CNT complex.

Effect of functionalization on drug delivery potential of carbon nanotubes

The main aim of the present investigation was to explore the effect of functionalization on drug delivery potential of carbon nanotubes (CNTs) and to compare the in vitro and in vivo cancer targeting potential of doxorubicin HCL (DOX)-loaded ox-/multi-walled CNTs (MWCNTs), DOX-loaded PEG-MWCNTs and DOX-loaded FA-PEG-MWCNTs. The DOX/PEG-FA-MWCNTs showed enhanced cytotoxicity and were most preferentially taken up by the cancerous cells. The obtained results also support the extended resistance time and sustained release profile of drug-loaded surface-engineered MWCNTs. Overall, we concluded that the developed MWCNTs nanoformulations have higher cancer targeting potential.

Potential of carbon nanotubes in algal biotechnology.

A critical mass of knowledge is emerging on the interactions between plant cells and engineered nanomaterials, revealing the potential of plant nanobiotechnology to promote and support novel solutions for the development of a competitive bioeconomy. This knowledge can foster the adoption of new methodological strategies to empower the large-scale production of biomass from commercially important microalgae. The present review focuses on the potential of carbon nanotubes (CNTs) to enhance photosynthetic performance of microalgae by (i) widening the spectral region available for the energy conversion reactions and (ii) increasing the tolerance of microalgae towards unfavourable conditions occurring in mass production. To this end, current understanding on the mechanisms of uptake and localization of CNTs in plant cells is discussed. The available ecotoxicological data were used in an attempt to assess the feasibility of CNT-based applications in algal biotechnology, by critically correlating the experimental conditions with the observed adverse effects. Furthermore, main structural and physicochemical properties of single- and multi-walled CNTs and common approaches for the functionalization and characterization of CNTs in biological environment are presented. Here, we explore the potential that nanotechnology can offer to enhance functions of algae, paving the way for a more efficient use of photosynthetic algal systems in the sustainable production of energy, biomass and high-value compounds.

Influence of the Amount of Dispersed Suspension of Carbon Nano-Tubes on Physico-Mechanical Properties of Cement Mortar

Nanotechnology has become a driving power in most of the branches of industry recently and construction industry is not an exception. Therefore, this paper deals with the topical problem of using nanoparticles in concrete. Carbon nanotubes (CNTs) with exceptional physico-mechanical properties were used in the experimental part of the paper. Their potential for enhancing characteristics of common concrete is promising. A frequent problem of application of carbon nanotubes is their agglomeration, which is caused by high surface tension, Van der Waals force and high ratio of sides. This fact limits possibilities of application of CNTs and it is the main reason of rare use of the promising potential of CNTs. Formed agglomerations can be dispersed by adding energy from outside and if suitable surface active agent in the solution of CNTs and water is added, their re-agglomeration can be prevented. Experimental part of the paper focuses on possibilities of dispersing CNTs by means of ultrasonic homogenizer Bandelin Sonopulse HD 3200 and suitable surface-active substance. Tests specimens were prepared from a suspension of water and CNTs with two different proportions and development of physico-mechanical properties in time was observed. Results confirmed the trends described in foreign literature sources and gave valuable impulses for further attempts to use nanotechnology in concrete technology.

Carbon nanotubes activate macrophages into a M1/M2 mixed status: recruiting naïve macrophages and supporting angiogenesis.

The potential of carbon nanotubes (CNTs) in medical applications has been attracting constant research interest as well as raising concerns related to toxicity. The immune system serves as the first line of defense against invasion. In this work, interactions of oxidized multiwalled carbon nanotubes (MWCNT) with macrophages were investigated to unravel the activation profile of macrophages, using cytokine array, ELISA assay, transwell assay, confocal microscopy, and reactive oxygen species examination. Results show that MWCNT initiate phagocytosis of macrophages and upregulate CD14, CD11b, TLR-4/MD2, and CD206, which does not alter the MHCII expression of the macrophages. The macrophages engulfing MWCNT (MWCNT-RAW) secrete a large amount of MIP-1α and MIP-2 to recruit naïve macrophages and produce angiogenesis-related cytokines MMP-9 and VEGF, while inducing much lower levels of proinflammatory cytokines than those activated by LPS. In conclusion, MWCNT activate macrophages into a M1/M2 mixed status, which allows the cells to recruit naïve macrophages and support angiogenesis.