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In a recent work, we have briefly introduced a new structural index for water that, unlike previous indicators, was devised specifically for generic contexts beyond bulk conditions, making it suitable for hydration and nanoconfinement settings. In this work, we shall study this metric in detail, demonstrating its ability to reveal the existence of a fine-tuned interplay between the local structure and energetics in liquid water. This molecular principle enables the establishment of an extended hydrogen bond network, while simultaneously allowing for the existence of network defects by compensating for uncoordinated sites. By studying different water models and different temperatures encompassing both the normal liquid and the supercooled regime, this molecular mechanism will be shown to underlie the two-state behavior of bulk water. In addition, by studying functionalized self-assembled monolayers and diverse graphene-like surfaces, we shall show that this principle is also operative at hydration and nanoconfinement conditions, thus generalizing the validity of the two-liquid scenario of water to these contexts. This approach will allow us to define conditions for wettability, providing an accurate measure of hydrophobicity and a reliable predictor of filling and drying transitions. Hence, it might open the possibility of elucidating the active role of water in the broad fields of biophysics and materials science. As a preliminary step, we shall study the hydration structure and hydrophilicity of graphene-like systems (parallel graphene sheets and carbon nanotubes) as a function of the confinement dimensionality. [ABSTRACT FROM AUTHOR]

Due to fascinating physical properties powered by remarkable progress in chemical vapor deposition of high-quality epilayers, diamond thin films attract great attention for fabrication of nitrogen-vacancy-based solid-state spin systems capable of operating in ambient conditions. To date, diamond heteroepitaxy via bias-enhanced nucleation is an unavoidable method for reliable wafer-scale film manufacturing. In this work, we analyze the coalescence phenomena in nitrogen doped, heteroepitaxial diamond epilayers, with a particular focus on their specific role in the annihilation of macroscopic crystal irregularities such as grain boundaries, non-oriented grains, and twinned segments. Here, we also report on the growth mechanism for the "primary" crystal orientation along with a predominant formation of two different types of boundaries highlighting the {011}-type as a main source of the crystal lattice irregularities. [ABSTRACT FROM AUTHOR]

Hybrid spin-mechanical systems offer a promising platform for advancing quantum science and technology. However, practical implementation of applications within these hybrid quantum systems demands the seamless integration of supplementary physical components. In this context, we present a proposal for a multi-mode spin-mechanical setup, featuring the utilization of three-mode coupling nanomechanical carbon nanotube (CNT) resonators. These resonators interact with each other via a phase-dependent phonon-exchange mechanism, which is coupled to the same nitrogen vacancy (NV) centers in diamond. Based on the modulation of the phonon–phonon coupling phase and leveraging the triple Fano-like resonance phenomenon, a tripling of electromagnetically induced transparency (EIT) becomes achievable within the system. This tripling is accompanied by swift dispersion, leading to a subtle advancement or delay in outcomes. The phenomenon of triple Fano-like resonance, alongside the resulting triple EIT, engenders noteworthy slow-to-fast and fast-to-slow light effects, which is theoretically demonstrated in CNT resonators, with both identical and distinct frequencies. The findings underscore that CNT resonators with varying frequencies can evoke a more pronounced transition in the slow–fast–slow and fast–slow–fast light effects. This study lays the foundation for the application of phonon-mediated optical information storage and processing. [ABSTRACT FROM AUTHOR]

Many researchers observed enhanced water flow through carbon nanotubes (CNTs) and attributed the reason to large slips. Even after taking significant slip effects into account, there remain unaddressed observations of significant improvements in flow rates. As CNTS are deformable, we represent nanotubes with a deformable-wall using a linear pressure–area relationship. We assume lubrication assumption, and using the properties of nanoconfined water, we derive the model for deformable-nanotubes. We validated our derived model in its limiting cases with the previously reported results in the literature. We compare the predictions by our deformable-wall and rigid-wall model with the experimental results and the MD-simulation predictions by multiple literature studies. Many studies were well-predicted by the rigid-wall model with slips. However, we find that there are many studies with high porosity and thin wall tubes, where elasticity or deformability of the tube is essential in modeling, which is well-predicted by our deformable-wall model with slips. In our study, we focus on investigating the impact of two key factors: the deformability, and the slip length on the flow rate. We find that the flow rate inside the tube increases as the deformability increases or the thickness T and elastic modulus E of the tube-wall decrease). We also find that the flow rate in deformable tubes scales as m ˙ deformable ∼ 1 / α 0 for (Δ p / α A o ) ≪ 1 , m ˙ deformable ∼ 1 / α for (Δ p / α A o ) ∼ O (10 − 1) and m ˙ deformable ∼ α 2 for (Δ p / α A o ) ∼ O (1). Further, for a given deformability, the percentage change in flow rate in the smaller diameter of the tube is much larger than the larger diameter. As the tube diameter decreases for the given pressure, Δ m ˙ / m ˙ increases. We find that for rigid-tube, the flow rate varies m ˙ rigid ∼ Δ p , whereas for the deformable-tubes, the flow rate scales as m ˙ deformable ∼ Δ p 2 for (Δ p / α A o ) ∼ O (10 − 1) , and finally to m ˙ deformable ∼ Δ p 3 for (Δ p / α A o ) ∼ O (1). We further find that slip also significantly increases flow rate, but, deformability has more substantial effect. [ABSTRACT FROM AUTHOR]

It is a known and experimentally verified fact that the flow of pressure-driven nanoconfined fluids cannot be accurately described by the Navier–Stokes (NS) equations with non-slip boundary conditions, and the measured volumetric flow rates are much higher than those predicted by macroscopical continuum models. In particular, the flow enhancement factors (the ratio between the flow rates directly measured by experiments or simulations and those predicted by the non-slip NS equation) reported by previous studies have more than five orders of magnitude differences. We showcased an anomalous phenomenon in which the flow enhancement exhibits a non-monotonic correlation with fluid pressure within the carbon nanotube with a diameter of 2 nm. Molecular dynamics simulations indicate that the inconsistency of flow behaviors is attributed to the phase transition of nanoconfined fluid induced by fluid pressures. The nanomechanical mechanisms are contributed by complex hydrogen-bonding interactions and regulated water orientations. This study suggests a method for explaining the inconsistency of flow enhancements by considering the pressure-dependent molecular structures. [ABSTRACT FROM AUTHOR]

The sluggish oxygen evolution reaction (OER) in overall electrocatalytic water splitting poses a significant challenge in hydrogen production. A series of transition metal phosphides are emerging as promising electrocatalysts, effectively modulating the charge distribution of surrounding atoms for OER. In this study, a highly efficient OER electrocatalyst (CoP-CNR-CNT) was successfully synthesized through the pyrolysis and phosphatization of a Co-doped In-based coordination polymer, specifically InOF-25. This process resulted in evenly dispersed CoP nanoparticles encapsulated in coordination polymer-derived carbon nanoribbons. The synthesized CoP-CNR-CNT demonstrated a competitive OER activity with a smaller overpotential (η10) of 295.7 mV at 10 mA cm-2 and a satisfactory long-term stability compared to the state-of-the-art RuO2 (η10 = 353.7 mV). The high OER activity and stability can be attributed to the high conductivity of the carbon network, the abundance of CoP particles, and the intricate nanostructure of nanoribbons/nanotubes. This work provides valuable insights into the rational design and facile preparation of efficient non-precious metal-based OER electrocatalysts from inorganic–organic coordination polymers, with potential applications in various energy conversion and storage systems. [ABSTRACT FROM AUTHOR]

The carbon nano-peapod is a representative structure with interlayer van der Waals (vdW) interactions, in which encapsulated fullerene molecules play a critical role in modulating the transport properties of the carbon nanotubes (CNTs). In particular, their influence on the thermal transport characteristics has been the focal point of considerable attention. In this study, we trained an accurate machine learning potential for fullerene-encapsulated CNTs based on the efficient NEP model to investigate their thermal properties. Using equilibrium molecular dynamics simulation along with the spectral decomposition method for thermal conductivity, we find that the thermal conductivity of fullerene-encapsulated CNTs is roughly 55 % lower than that of empty CNTs, aligning with experimental observations for CNT bundles with fullerene encapsulation [Kodama et al., Nat. Mater. 16, 892 (2017)]. The research suggests that weak vdW interactions between both the fullerene and CNTs, as well as between fullerene molecules themselves, hinder phonon propagation. The encapsulated fullerene contributes to an increase in phonon scattering within the CNTs, ultimately leading to a reduction in thermal conductivity. We utilized machine learning potential to investigate the structure of fullerene-encapsulated CNTs and their heat transport property. This approach provides valuable insights for performance research of complex systems featuring interlayer vdW interactions. [ABSTRACT FROM AUTHOR]

Programmable locomotion of molecules inside the carbon nanotube (CNT) has a significant role in controlling the reactions and delivery systems based on nanotubes. Using molecular dynamics (MD) simulations as well as the theoretical approach, we evaluate the oscillation of C60 inside the CNTs that are subjected to strain gradients from both sides. The molecular dynamics simulations are implemented by LAMMPS open-source software. Using this program, the van der Waals (vdW) interactions are established between C60 and nanotube, and the simulations are performed in canonical ensemble. The strain gradient applied on CNT provides the restoring force of the oscillation of C60. The potential energy of fullerene finds the minimum value at the unstrained region of CNT, which makes it the equilibrium point of oscillation. The amplitude of the oscillations is shown to be related to the thermal energy of C60. The frequency of the oscillations depends on the magnitude of the strain gradient applied on the nanotubes. At higher strain gradients of CNTs, we observe the increase in the frequency due to the increase in the restoring force acting on the fullerene molecule. We exploit the strained carbon nanotubes to control the position of C60 inside the nanotube. It has been shown that by changing the strain gradient of CNT, it is possible to steer the locomotion of C60 to different points inside the nanotube. [ABSTRACT FROM AUTHOR]

For over half a century, traditional silicon-based integrated circuits (ICs) have been the basis of computational electronics and are widely used in computers, cell phones, and other fields. With the rapid development of human society, silicon-based semiconductor technology is approaching its physical and engineering limits. Our increasing diversity of non-traditional computing needs, such as ultra-small, ultra-fast, ultra-low-power wearables, and space radiation protection, is driving the search for new electronic materials. Semiconducting single-walled carbon nanotubes (s-SWCNTs) have many excellent electrical properties, such as high carrier mobility and high ballistic transport, making them strong candidates for new semiconductor materials in the post-Moore era. Carbon-based electronic technology has been developed for over 20 years, and the fundamental issues such as the material purification of s-SWCNTs, preparation prospects of s-SWCNT-based field-effect transistors (CNT FETs), and device physics based on CNT FETs have been basically solved. However, the chiral diversity of s-SWCNTs may lead to problems such as fluctuations in the electrical performance of CNT FETs, limiting the application of s-SWCNTs in high-end ICs. Monochiral s-SWCNTs not only have excellent electrical properties but also have a controllable structure and uniformity, which are crucial for the high-end IC of CNTs. However, some problems exist in the purity and yield of monochiral s-SWCNT preparation and the optimization of monochiral CNT FETs. Therefore, the chiral sorting of CNTs is reviewed in this paper, and the progress of polymer reprocessing in chiral separation is highlighted. Then, the research progress of monochiral CNT FETs is introduced, and possible development directions are summarized and analyzed. Finally, the application prospects of chiral-enriched s-SWCNTs include challenges and future opportunities. [ABSTRACT FROM AUTHOR]

We report on the studies of conduction mechanism, direct current conductance, and 1 f -noise of cellulose nanofiber (CNF) and multiwalled carbon nanotube (MWCNT) composites. The composites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The temperature- and voltage-dependence of the dc conductance Σ were, respectively, probed to investigate the charge transport mechanism and the electrical response of the composite. At room temperature, the increase in Σ with wt. % of MWCNT ϕ showed typical percolation behavior. The Σ − T behavior was fitted to the combination of one-dimensional variable range hopping and the fluctuation-induced tunneling, which were attributed to hopping of charge carriers through 1D MWCNTs and the tunneling of charge carriers between the bundles of MWCNTs, respectively. The non-Ohmic electrical conduction was characterized by the onset voltage V 0 (T) which scaled with Ohmic conductance Σ 0 as V 0 (T) ∼ Σ 0 (T) x T , with x T being the onset exponent increased with ϕ. A scaling description based on the data collapse method was adopted to find the parameters V 0 (T) and x T. The noise power spectrum S V (f) followed the relation S V (f) ∼ V β with two different power-laws: β 1 in the Ohmic and β 2 in the non-Ohmic region (β 1 > --> β 2). Interestingly, this change in power-laws occurs at the same V 0 (T) obtained from Σ − V curves. A simple model was proposed to explain the noise behavior after V 0 (T). It is expected that such electrical characterization of CNF-MWCNT nanopaper composite would open up their possibility of application in flexible electronic devices, intelligent networks, sensors, and actuators. [ABSTRACT FROM AUTHOR]

Experimental observations unambiguously reveal quasi-frictionless water flow through nanometer-scale carbon nanotubes (CNTs). Classical fluid mechanics is deemed unfit to describe this enhanced flow, and recent investigations indicated that quantum mechanics is required to interpret the extremely weak water–CNT friction. In fact, by quantum scattering, water can only release discrete energy upon excitation of electronic and phononic modes in the CNT. Here, we analyze in detail how a traveling water molecule couples to both plasmon and phonon excitations within a sub-nanometer, periodic CNT. We find that the water molecule needs to exceed a minimum speed threshold of ∼50 m/s in order to scatter against CNT electronic and vibrational modes. Below this threshold, scattering is suppressed, as in standard superfluidity mechanisms. The scattering rates, relevant for faster water molecules, are also estimated. [ABSTRACT FROM AUTHOR]

The unique physical properties of carbyne, a novel carbon nanostructure, have attracted considerable interest in modern nanotechnology. While carbyne synthesis has been accomplished successfully using diverse techniques, the underlying mechanisms governing the carbon monoxide-dependent catalytic synthesis of endohedral carbyne remain poorly understood. In this simulation-based study, we investigate the synthesis of endohedral carbyne from carbon and carbon monoxide radicals in the presence of a nickel catalyst inside double-walled carbon nanotubes with a (5,5)@(10,10) structure. The outcome of our investigation demonstrates that the incorporation of the carbon atom within the Nin@(5,5)@(10,10) model system initiates the formation of an elongated carbon chain. In contrast, upon the introduction of carbon monoxide radicals, the growth of the carbyne chain is inhibited as a result of the oxidation of endohedral nickel clusters by oxygen atoms after the initial steps of nucleation. Our findings align with prior theoretical, simulation, and experimental investigations, reinforcing their consistency and providing valuable insights into the synthesis of carbyne-based nanodevices that hold promising potential for future advancements in nanotechnology. [ABSTRACT FROM AUTHOR]

We demonstrate a high electron conductivity (>102 S/cm and up to 103 S/cm) of tungsten suboxide W18O52.4−52.9 (or equivalently WO2.91−2.94) nanotubes (2–3 nm in diameter, ∼μm long). The conductivity is measured in the temperature range of 120–300 K by a four-probe scanning tunneling microscope in ultrahigh vacuum. The nanotubes are synthesized by a low-temperature and low-cost solvothermal method. They self-assemble in bundles of hundreds of nanotubes forming nanowires (∼μm long, few tens nm wide). We observe a large anisotropy of the conductivity with a ratio (longitudinal conductivity/perpendicular conductivity) of ∼105. A large fraction of them (∼65%–95%) shows a metallic-like, thermal activation-less electron transport behavior. Few of them, with a lower conductivity from 10 to 102 S/cm, display a variable range hopping behavior. In this latter case, a hopping barrier energy of ∼0.24 eV is inferred in agreement with the calculated energy level of the oxygen vacancy below the conduction band. This result is in agreement with a relative average concentration of oxygen vacancies of ∼3%, for which a semiconductor-to-metal transition was theoretically predicted. These tungsten suboxide nanostructures are prone to a wide range of applications in nanoelectronics. [ABSTRACT FROM AUTHOR]

Developing bifunctional catalysts for overall water splitting with high activity and durability at high current density remains a challenge. In an attempt to overcome this bottleneck, in this work, unique CoNiFe-layered double hydroxide nanoflowers are in situ grown on nickel-iron (NiFe) foam through a corrosive approach and following a chemical vapor deposition process to generate nitrogen-doped carbon nanotubes at the presence of melamine (CoNiFe@NCNTs). The coupling effects between various metal species act a key role in accelerating the reaction kinetics. Moreover, the in situ formed NCNTs also favor promoting electrocatalytic activity and stability. For oxygen evolution reaction it requires low overpotentials of 330 and 341 mV in 1M KOH and 1M KOH + seawater to drive 500 mA cm−2. Moreover, water electrolysis can be operated with CoNiFe@NCNTs as both anode and cathode with small voltages of 1.95 and 1.93 V to achieve 500 mA cm−2 in 1M KOH and 1M KOH + seawater, respectively. [ABSTRACT FROM AUTHOR]

The electric polarizability and the spread of the total position tensors are used to characterize the metallic vs insulator nature of large (finite) systems. Finite clusters are usually treated within the open boundary condition formalism. This introduces border effects, which prevent a fast convergence to the thermodynamic limit and can be eliminated within the formalism of periodic boundary conditions. Recently, we introduced an original approach to periodic boundary conditions, named Clifford boundary conditions. It considers a finite fragment extracted from a periodic system and the modification of its topology into that of a Clifford torus. The quantity representing the position is modified in order to fulfill the system periodicity. In this work, we apply the formalism of Clifford boundary conditions to the case of carbon nanotubes, whose treatment results in a particularly simple zigzag geometry. Indeed, we demonstrate that at the Hückel level, these nanotubes, either finite or periodic, are formally equivalent to a collection of non-interacting dimerized linear chains, thus simplifying their treatment. This equivalence is used to describe some nanotube properties as the sum of the contributions of the independent chains and to identify the origin of peculiar behaviors (such as conductivity). Indeed, if the number of hexagons along the circumference is a multiple of three, a metallic behavior is found, namely a divergence of both the (per electron) polarizability and total position spread of at least one linear chain. These results are in agreement with those in the literature from tight-binding calculations. [ABSTRACT FROM AUTHOR]

The temperature coefficient of resistivity (θ T) of carbon-based materials is a critical property that directly determines their electrical response upon thermal impulses. It could have metal- (positive) or semiconductor-like (negative) behavior, depending on the combined temperature dependence of electron density and electron scattering. Its distribution in space is very difficult to measure and is rarely studied. Here, for the first time, we report that carbon-based micro/nanoscale structures have a strong non-uniform spatial distribution of θ T. This distribution is probed by measuring the transient electro-thermal response of the material under extremely localized step laser heating and scanning, which magnifies the local θ T effect in the measured transient voltage evolution. For carbon microfibers (CMFs), after electrical current annealing, θ T varies from negative to positive from the sample end to the center with a magnitude change of >130% over <1 mm. This θ T sign change is confirmed by directly testing smaller segments from different regions of an annealed CMF. For micro-thick carbon nanotube bundles, θ T is found to have a relative change of >125% within a length of ∼2 mm, uncovering strong metallic to semiconductive behavior change in space. Our θ T scanning technique can be readily extended to nm-thick samples with μm scanning resolution to explore the distribution of θ T and provide a deep insight into the local electron conduction. [ABSTRACT FROM AUTHOR]

The impact of a time-varying external magnetic field on carbon nanotubes has been studied using Maxwell's equations in the mentioned articles. However, the Maxwell's equations are erroneously presented in the papers. The incorrect Maxwell's equations, their derivatives, and the Lorentz force equations have all been examined in this work. In this article, we have endeavored to ensure that the equations are formatted correctly and have made an effort to do so. We have made an effort to intuitively correct the equations' errors. We did not comment on the other portions of the mentioned articles; instead, we restricted ourselves to the examination of the impact of Maxwell's equations and Lorentz force equations. [ABSTRACT FROM AUTHOR]

Spin–orbit coupling in a chiral medium is generally assumed to be a necessary ingredient for the observation of the chirality-induced spin selectivity (CISS) effect. However, some recent studies have suggested that CISS may manifest even when the chiral medium has zero spin–orbit coupling. In such systems, CISS may arise due to an orbital polarization effect, which generates an electromagnetochiral anisotropy in two-terminal conductance. Here, we examine these concepts using a chirally functionalized carbon nanotube network as the chiral medium. A transverse measurement geometry is used, which nullifies any electromagnetochiral contribution but still exhibits the tell-tale signs of the CISS effect. This suggests that CISS may not be explained solely by electromagnetochiral effects. The role of nanotube spin–orbit coupling on the observed pure CISS signal is studied by systematically varying nanotube diameter. We find that the magnitude of the CISS signal scales proportionately with the spin–orbit coupling strength of the nanotubes. We also find that nanotube diameter dictates the supramolecular chirality of the medium, which in turn determines the sign of the CISS signal. [ABSTRACT FROM AUTHOR]

Carbon nanotubes can serve as one-dimensional nanoreactors for the in-tube synthesis of various nanostructures. Experimental observations have shown that chains, inner tubes, or nanoribbons can grow by the thermal decomposition of organic/organometallic molecules encapsulated in carbon nanotubes. The result of the process depends on the temperature, the diameter of the nanotube, and the type and amount of material introduced inside the tube. Nanoribbons are particularly promising materials for nanoelectronics. Motivated by recent experimental results observing the formation of carbon nanoribbons inside carbon nanotubes, molecular dynamics calculations were performed with the open source LAMMPS code to investigate the reactions between carbon atoms confined within a single-walled carbon nanotube. Our results show that the interatomic potentials behave differently in quasi-one-dimensional simulations of nanotube-confined space than in three-dimensional simulations. In particular, the Tersoff potential performs better than the widely used Reactive Force Field potential in describing the formation of carbon nanoribbons inside nanotubes. We also found a temperature window where the nanoribbons were formed with the fewest defects, i.e., with the largest flatness and the most hexagons, which is in agreement with the experimental temperature range. [ABSTRACT FROM AUTHOR]

In gas transport systems of the nanoscale, fluid–surface interactions become the main forces governing the evolution of the flow state. In ideal nanoscale systems, such as atomically smooth carbon nanotubes, the characteristic lengths reduce to such an extent that the non-equilibrium entrance region comprises a large proportion of the domain. In this regime, the added effective resistance induced by the non-equilibrium entrance region becomes large enough that classical effusion models break down. The mechanisms behind the resistance in this regime are still poorly understood. A stochastic model of interfacial resistance is developed here, which allows for the determination of the effective diffusion coefficient via a novel finite-difference solution. We use this method to model free-molecular gas flow through long nanotubes, showing that such non-equilibrium effects may be present in systems of length scales currently within manufacturing capabilities. Finally, this model is used to discuss gas separation through aligned carbon nanotube arrays, with a focus on the effect of membrane length on the separation of a H2–CH4 mixture. [ABSTRACT FROM AUTHOR]

Abstract We present the first work of the synthesis mechanism from graphene quantum dots (GQDs) to carbon nanotubes (CNTs) by an ion-sputtering assisted chemical vapor deposition. During the annealing process, a Pt thin film deposited by the ion-sputtering was dewetted and agglomerated to form many nanometer-sized particles, leading to Pt nanoparticles (PtNPs) that can act as catalysts for creating carbon allotropes. The shape of the allotropes can be effectively tailored from GQDs to CNTs by controlling three key parameters such as the dose of catalytic ions (D), amounts of carbon source (S), and thermal energy (T). In our work, it was clearly proved that the growth control from GQDs to CNTs has a comparably proportional relationship with D and S, but has a reverse proportional relationship with T. Furthermore, high-purity GQDs without any other by-products and the CNTs with the cap of PtNPs were generated. Their shapes were appropriately controlled, respectively, based on the established synthesis mechanism. Graphical abstract

This study aims to fabricate heterogeneous CNTs/Al composites with a hierarchical structure using powder metallurgy techniques. The hierarchical composites are composed of alternating layers with and without CNTs. Tensile testing of the as-sintered sample, with a 3.5 mm width and containing 0.5 wt% CNTs, revealed an ultimate tensile strength of 249 MPa and 11.8 % elongation to failure. This shows an improvement in overall mechanical properties while maintaining the superior ductility of the alloy and the high strength of uniform composites. Indicating an effective overcoming of the traditional trade-off between strength and ductility. Several strengthening mechanisms have been discussed, including load transfer, grain refinement, and extra dislocations. Coordinated deformation and retarding effect during crack propagation can significantly enhance ductility. Furthermore, the incorporation of reinforcement increased the thermal conductivity by 18.6% due to the excellent thermal characteristics of CNTs. To investigate the intrinsic principles, a parallel and series model was developed to simulate the arrangement of CNTs in the Al matrix. Molecular dynamics (MD) simulations revealed the heat transfer mechanism through the electron-phonon coupling effect. This study proposes a new approach for creating metal materials that have both strength and ductility, while also improving their thermal conductivity.

Abstract The piezoresistive effect of materials can be adopted for a plethora of sensing applications, including force sensors, structural health monitoring, motion detection in fabrics and wearable, etc. Although metals are the most widely adopted material for sensors due to their reliability and affordability, they are significantly affected by temperature. This work examines the piezoresistive performance of carbon nanoparticle (CNP) bulk powders and discusses their potential applications based on strain-induced changes in their resistance and displacement. The experimental results are correlated with the characteristics of the nanoparticles, namely, dimensionality and structure. This report comprehensively characterizes the piezoresistive behavior of carbon black (CB), onion-like carbon (OLC), carbon nanohorns (CNH), carbon nanotubes (CNT), dispersed carbon nanotubes (CNT-D), graphite flakes (GF), and graphene nanoplatelets (GNP). The characterization includes assessment of the ohmic range, load-dependent electrical resistance and displacement tracking, a modified gauge factor for bulk powders, and morphological evaluation of the CNP. Two-dimensional nanostructures exhibit promising results for low loads due to their constant compression-to-displacement relationship. Additionally, GF could also be used for high load applications. OLC’s compression-to-displacement relationship fluctuates, however, for high load it tends to stabilize. CNH could be applicable for both low and high loading conditions since its compression-to-displacement relationship fluctuates in the mid-load range. CB and CNT show the most promising results, as demonstrated by their linear load-resistance curves (logarithmic scale) and constant compression-to-displacement relationship. The dispersion process for CNT is unnecessary, as smaller agglomerates cause fluctuations in their compression-to-displacement relationship with negligible influence on its electrical performance.

Joule dissipation has an important role in the conversion of mechanical energy to heat within a fluid due to the internal friction and viscosity. Moreover, Darcy friction is a measure of the resistance to flow in a porous medium. In response to the efficient heat transfer performance, a robust statistical approach was established to optimize the heat transfer rate in a two-dimensional flow of a nanofluid over a permeable surface embedded with a porous matrix. The electrically conducive fluid affected the flow phenomena to include a carbon nanotube nanoparticle in the conventional liquid water for the enhanced heat transfer properties; additionally, the power-law heat flux model was considered. Appropriate transformation rules were adopted to obtain a non-dimensional system that brought a developed model equipped with several factors. The traditional numerical technique (i.e., shooting based Runge-Kutta) was proposed to handle the coupled nonlinear system. Furthermore, the statistical response surface methodology (RSM) was adopted to obtain an efficient optimized model for the heat transportation rate of the considered factors. An analysis of variance (ANOVA) was utilized to validate the result of the regression analysis. However, it was evident that the nanoparticle concentrations were useful to augment the fluid velocity and the temperature distributions; the statistical approach adopted for the heat transfer rate displayed an optimized effect as compared to a conventional effect.

Abstract Polylactic acid (PLA) is a bioresorbable and biodegradable polymer extensively used in various biomedical and engineering applications. In this study, we investigated the mass loss and thermal properties of PLA-multi-walled carbon nanotube (MWCNT) composites under simulated physiological conditions. The composites were prepared by melting PLA with 0.1, 0.5, 1.0, and 5.0 wt% MWCNTs using an ultrasonic agitator, and FTIR analysis confirmed composite formation. Subsequently, the composites were subjected to hydrolysis under simulated physiological conditions (pH 7.4 and 37 °C) for up to 60 days. The results revealed that the mass loss of the composites decreased with increasing MWCNT content, suggesting that the presence of MWCNTs decelerated the hydrolysis process. On day 58, the mass loss of pure PLA was 12.5%, decreasing to 8.34% with 0.1% MWCNT, 5.94% with 0.5% MWCNT, 4.59% with 1% MWCNT, and 3.54% with 5.0% MWCNT. This study offers valuable insights into the behavior of PLA-MWCNT composites under physiologically simulated conditions, facilitating the development of new polymer composites with enhanced thermal stability and degradation resistance for biomedical applications.

Abstract The postharvest life of cut flowers is limited, which is a major challenge and varies greatly depending on plant varieties, cut flower stage, flower length of the harvested shoots, and storage conditions including postharvest treatments. As a result, improving the vase life and quality of cut flowers in regulating postharvest characteristics and overcoming these challenges is critical to the horticulture business. Novel engineered nanocomposites were created and tested for possible impacts on flower bud opening, postharvest life extension, longevity regulation, and preservation and enhancement of the strength and appearance of cut flowers. The experiment was conducted as a factorial experiment using a completely randomized design (CRD) with two factors. The first factor was two holding solutions (without or with sucrose at 20 gL−1). The second factor was 12 pulsing treatments for 24 h; distilled water as a control, 75 ppm GA3, multi-walled carbon nanotubes MWCNTs at 10, 20, 30, 40, and 50 ppm, and MWCNTs (10, 20, 30, 40, and 50 ppm)/GA3 (75 ppm) composites; each treatment had 3 replicates, for a total of 72 experimental units. In the present study, gibberellic acid (GA3) was synthesized in functionalized (MWCNT/GA3 composites) as a novel antisenescence agent, and their effect on the vase life quality of cut rose flowers Rosa hybrida cv. ‘Moonstone’ was compared by assaying several parameters critical for vase life. The adsorption of GA3 on MWCNTs was proven by performing FTIR spectroscopy which ensures that the formation of the MWCNTs/GA3 composite preserves the nanostructure and was examined by high-resolution transmission electron microscopy (HR-TEM). The results revealed that sucrose in the holding solution showed a significant increase in fresh weight, flower diameter, and vase life by 10.5, 10.6, and 3.3% respectively. Applying sucrose with MWCNTs 20 ppm/GA3 75 ppm composites or MWCNTs 20 ppm alone, was critical for the significant increase in flower opening by 39.7 and 28.7%, and longevity by 34.4 and 23.2%, respectively, and significantly increased chlorophyll a, b, total chlorophyll, anthocyanin, total phenolic content, and 2,2-Diphenyl-1-picrylhydrazyl scavenging activity as compared to the control.

In order to create an electrochemical sensor for doxorubicin (DXB), an effective cancer treatment, multi-walled carbon nanotubes—a modified glassy carbon electrode made of mesoporous silica nanocomposite—were created in this work. Examining the mSiO2@MWCNTs nanocomposite's structure and composition using FTIR, XPS, and SEM revealed the combination of mSiO2 and MWCNTs nanostructure on the modified electrode surface. Studies on the electrochemical determination of DXB utilizing cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methodologies showed that mSiO2@MWCNTs/GCE exhibited excellent sensitivity, selectivity, and precision. MWCNTs and mesoporous silica in the improved electrode work together to improve the sensor's overall performance by enhancing stability and sensitivity in the electrochemical oxidation of DXB. The sensor's linear range was found to be 30–750 μM, with a sensitivity of 0.05123 μA/μM and a detection limit of 14 nM, according to the results. The mSiO2@MWCNTs/GCE shows properties suitable for real sample analysis. The creation of this sensor represents a significant advancement in the field of electrochemical sensors and may open the door to the development of more precise and focused drug detection techniques.

Topological indices (TIs) are mathematical codings of the molecular graphs that predict the physicochemical, biological, toxicological, and structural properties of the chemical compounds. To evaluate the physical and chemical properties of molecules, numerous TIs have been studied in the literature. In chemical research, a nanostructure is one of the most important and frequently studied substances. It was created using molecular-scale engineering mechanisms. Zagreb indices (ZIs) are the majority studied by TIs. TIs are categorized based on their degree, distance, and polynomial. Connection-based topological indices (ZCIs), one of these TIs, are extremely important. In this article, we compute several connection-based topological indices for carbon nanotube graphs. We obtain first ZCI (1st ZCI) and second ZCI (2nd ZCI) and modified first ZCI (1*st ZCI), modified second ZCI (2*nd ZCI), modified third ZCI (3*rd ZCI), and modified fourth ZCI (4*th ZCI). Moreover, we compute multiplicative ZCI (MZCI), named as first MZCI (1st MZCI), second MZCI (2nd MZCI), third MZCI (3rd MZCI), fourth MZCI (4th MZCI), and modified first (1*st MZCI), modified second (2*nd MZCI), and modified third (3*rd MZCI) for carbon nanotube graphs.

Carbon nanotubes (CNTs) have drawn great attention as potential materials for energy conversion and storage systems such as batteries, supercapacitors, and fuel cells. Among these energy conversion and storage systems, the fuel cells had stood out owing to their high-power density, energy conversion efficiency and zero greenhouse gasses emission. In fuel cells, CNTs have been widely studied as catalyst support, bipolar plates and electrode material due to their outstanding mechanical strength, chemical stability, electrical and thermal conductivity, and high specific surface area. The use of CNT has been shown to enhance the electrocatalytic performance of the catalyst, corrosion resistivity, improve the transmission performance of the fuel cell and reduce the cost of fuel cells. The use of CNTs in fuel cells has drastically reduced the use of noble metals. However, the major drawback to the utilization of pristine CNTs in fuel cells are; poor dispersion, agglomeration, and insolubility of CNTs in most solvents. Surface engineering of CNTs and CNT nanocomposites has proven to remarkably remedy these challenges and significantly enhanced the electrochemical performance of fuel cells. This review discusses the different methods of surface modification of CNTs and their nanocomposite utilized in fuel cell applications. The effect of CNTs in improving the performance of fuel cell catalyst, membrane electrode assembly and bipolar plates of fuel cells. The interaction between the CNTs catalyst support and the catalyst is also reviewed. Lastly, the authors outlined the challenges and recommendations for future study of surface functionalized CNTs composite for fuel cell application.

Abstract In this paper, the quantum effects of fine scaling on the buckling behavior of carbon nanotubes (CNTs) under axial loading are investigated. Molecular mechanics and quantum mechanics are respectively utilized to study the buckling behavior and to obtain the molecular mechanics coefficients of fine-scale nanotubes. The results of buckling behavior of CNTs with different chiralities with finite and infinite dimensions are given, and a comparison study is presented on them. The differences between finite and infinite nanotubes reflect the quantum effects of fine scaling on the buckling behavior. In addition, the results show that the dimensional changes highly affect the mechanical properties and the buckling behavior of CNTs to certain dimensions. Moreover, dimensional changes have a significant effect on the critical buckling strain. Beside, in addition to the structure dimensions, the arrangement of structural and boundary atoms have a major influence on the buckling behavior.

Carbon nanotubes (CNTs) are gaining popularity due to their expanding uses in industrial and technical processes, such as geothermal reservoirs, water and air filters, coatings, solar collection, ceramic material reinforcement, electrostatic dissipation, etc. In addition, the CNTs have superior electrical conductivity and biocompatibility. Based on the aforementioned applications, the current work examines the time-dependent and Darcy–Forchheimer flow of water/glycerin-based Casson hybrid nanofluid formed by single-walled CNTs and multi-walled CNTs over a Riga plate under velocity slip. The energy expression is modeled through nonlinear thermal radiation and viscous dissipation impacts. The incorporation of convective boundary condition into the current model improves its realism. By employing suitable variables, the governing models are re-framed into ordinary differential equations. The bvp4c and the homotopy analysis method are used to find the computational results of the re-framed equations and boundary conditions. The novel characteristics of a variety of physical parameters on velocity, temperature, skin friction coefficient (SFC), and local Nusselt number (LNN) are discussed via graphs, charts, and tables. It is found that the fluid velocity decays when enriching the Forchheimer number, unsteady and porosity parameters. The radiation parameter plays an opposite role in convective heating and cooling cases. The modified Hartmann number enhances the surface drag force, and the Forchheimer number declines the SFC. The unsteady parameter develops the heat transfer rate, and the Forchheimer number suppresses the LNN. The simulated flow problem has many applications in engineering sectors, including ceramic manufacture, heating and cooling systems, energy storage units, thermodynamic processes, and other fields.

Abstract Hydroquinone (HQ), catechol (CC) and nitrite (NT) are considered aquatic environmental pollutants. They are highly toxic, harm humans’ health, and damage the environment. Thus, in the present work we introduce a simple and efficient electrochemical sensor for determination of HQ, CC, and NT simultaneously in wastewater sample. The sensor is fabricated by modifying the surface of a glassy carbon electrode (GCE) by two successive thin films from poly(3,4-ethylenedioxythiophene) (PEDOT) and a mixture of carbon nanotubes-graphene oxide (CNT-GRO). Under optimized conditions the HQ, CC, and NT are successfully detected simultaneously in wastewater sample with changing their concentrations in the ranges (0.04 → 100 µM), (0.01 → 100 µM) and (0.05 → 120 µM), the detection limits are 8.5 nM, 3.8 nM and 6.1 nM, respectively. Good potential peak separations: 117 mV and 585 mV are obtained between the HQ-CC, and CC-NT. The sensor has an excellent catalytic capability toward the oxidation of HQ, CC, and NT due to good synergism between its composite components: PEDOT, GRO and CNTs. The features of the sensor are large active surface area, good electrical conductivity, perfect storage stability, good reproducibility, anti-interference capability and accepted recovery rate for HQ, CC, and NT determination in wastewater sample.

Abstract This study deals with the process of developing and optimizing the spray coating method for large-area deposition of carbon nanotubes. Carbon nanotubes have excellent electrical and thermal properties and strength, so they are used in various fields of application. However, existing deposition methods have limitations. In this study, the possibility of the spray coating method for large-area deposition of carbon nanotubes is presented, and additional conditions for this are introduced. A spray coating solution was prepared using dichlorobenzene as a solvent for 3 mg carbon nanotubes. By controlling the spray coating speed, the spray coating conditions were optimized by analyzing the surface shape, structure, and resistance of the deposited carbon nanotubes. As a result, we confirmed the possibility of depositing carbon nanotubes on a large area through the spray coating method, and it is expected to contribute to increasing the application possibilities in industrial and scientific fields.

Prominent interfacial bonding can significantly improve the stress transfer efficiency between carbon fibers and matrix, which is the basis of efficient and long-term application of composites. In this paper, a bicomponent collaborative strategy was proposed to fully utilize the advantages of silicon nitride nanowires (SNs) and carbon nanotubes (CNTs) to optimize the interfacial strength of carbon fiber modified double matrix composites (CD), in which the double matrix was represented by polymers-hydroxyapatite and pyrocarbon-hydroxyapatite. The microstructure displayed that SNs were randomly distributed inside CD and completely wrapped by CNTs, which combined to form an interlocking structure. The mechanical and friction behavior of modified and unmodified composites was investigated. The compression strength and shear strength of CNTs-SNs modified carbon fiber/polymers-hydroxyapatite composites were 110 ± 2.39 MPa and 56 ± 1.13 MPa, displaying an increment of 69% and 87%. The wear rate was 0.4 × 10−14 ± 0.008 m3 N−1 m−1, exhibiting a 61% decline. The fracture morphologies were observed to analyze the strengthening mechanism. Interlocked CNTs-SNs could strengthen the effective bonding of fiber/matrix interface and SNs/matrix interface, provide lots of nucleation sites for the matrix, and enhance the matrix cohesion. The enhancement was further verified by a 56% increase in the compression strength (237 ± 4.67 MPa), a 235% increase in the shear strength (77 ± 1.53 MPa), a 78% decrease in wear rate (0.38 × 10−13 ± 0.011 m3 N−1 m−1) of CNTs-SNs modified carbon fiber/pyrocarbon-hydroxyapatite composites, indicating that CNTs-SNs played an indispensable role in making CD possess brilliant mechanical and biological friction properties.

Breast cancer is a severe global health issue that necessitates the development of dependable and sensitive technology for identifying the drugs used in its treatment. The present work aimed to evaluate the efficacy of paclitaxel (PTX) as a breast cancer treatment by fabricating composites of carbon nanotubes (CNTs) and β-cyclodextrin modified glassy carbon electrode (β-CD/CNT/GCE) for electrochemical sensing. FTIR, SEM, XPS, and XRD structural and chemical analyses demonstrated the effectiveness of the β-CD grafting onto CNT. Electrochemical studies using amperometry and cyclic voltammetry (CV) techniques showed that combining β-CD and CNTs in a nanocomposite improves the PTX sensor's sensitivity and selectivity while enhancing the benefits of each component separately. With a detection limit of 1.7 nM and a linear range of 5–1060 μM, the sensor's sensitivity of 0.8418 μA/μM and strong electrochemical response between the β-CD/CNT/GCE and PTX were demonstrated. Urine samples from a group of volunteers were collected to evaluate the PTX detection accuracy of the proposed sensor. The results showed respectable precision with a relative standard deviation of less than 4.72 % and significant recovery values greater than 96.00 %. This invention advances the field of personalised medicine and has wider implications for clinical diagnostics and pharmaceutical analysis.

3D printing has gained a spot within the industry during the last decade due to the advantages it presents regarding conventional manufacturing technologies. Nevertheless, the high processing time and the material waste due to the use of printing supports are still some of the main challenges that have to be addressed. In this research work, a simple strategy to minimize the processing time and the material waste is carried out through a two-stage processing method. Here, a flat specimen is obtained using a vat photopolymerization 3D printer, presenting a low curing degree. Then, the specimen is bent and subsequent post-curing treatments are performed to increase the cross-link density, thus fixing the desired shape. Furthermore, carbon nanotubes were used as nanoreinforcement for increasing the mechanical properties and exploiting their Joule heating capabilities for the thermal post-curing treatment, being way less energy-consuming (around 1W) than using a conventional oven (around 750 W). The results obtained with a proof-of-concept evinced the suitability of the proposed two-stage processing method to enhance the efficiency and sustainability of the 3D printing process. The printing time and the material waste were reduced by 94.3 % and 16.7 % on average, respectively, with regard to printing the part directly on its final desired shape, as well as showing a shape fixity ratio of around 98 %. Furthermore, an enhancement of the mechanical properties was obtained due to the reorientation of the printed layers during the two-stage processing.

Electro-induced two-way shape memory polymer is a kind of smart material which can realize bidirectional reversible actuation under current stimulation. However, due to the limitation of materials, there are few studies on the electro-induced two-way shape memory effect. Herein, the two-way shape memory effect of a new type of semi-crystalline thermoplastic polyamide elastomer (TPAE, T12) was systematically studied. The response strain (εact) of two-way shape memory effect for T12 under constant stress and stress-free condition could reach 16.4 % and 9.7 %, respectively. The introduction of multi-walled carbon nanotubes (CNTs) endowed the T12 material with good conductivity, and CNTs did not significantly influence the two-way shape memory performance of T12/CNTs composite. Moreover, when the content of CNTs was 5 wt%, the surface temperature of T12/CNTs composite could reach 36 °C–90 °C at a voltage of 90 V–150 V. Then, we realized the electro-induced two-way shape memory behavior of T12/CNTs composite through the construction of bilayer SEBS/T12/CNTs actuator. Therefore, T12 material, as a new two-way shape memory TPAE, has great application potential in aerospace, soft robotics, medical and other fields.

The graphite-reinforced epoxy resin composite (Gr/EP) is considered one of the promising solid lubricating materials. However, the low thermal conductivity and correlated poor wear resistance cause limitations to its tribological applications. With the expectation to improve the thermal conductivity and wear property, carbon nanotube (CNT)-reinforced copper foams (CNTs/Cuf) are introduced as 3-dimensional skeletons to reinforce Gr/EP composites. Herein, comprehensive testing was conducted to assess the wear resistance, thermal conductivity, microstructure, and wear morphology of the composites. The results revealed that incorporating Cu or CNTs/Cu foams into the Gr/EP matrix significantly enhanced thermal conductivity and wear resistance, with only minor elevation of the friction coefficients, which showed a consistent decline trend with increasing CNTs contents. Notably, with the CNT content of 0.159 wt%, the composites reached the favorable combination of a 25.4 % improvement in thermal conductivity and a 34 % reduction in wear rate compared to pure copper foam-reinforced Gr/EP composites.

Carbon nanotube field-effect transistors (CNTFETs) have been considered a strong candidate for post-Si era electronics due to the virtues of higher speed, lower power consumption, and multiple functionalities. The interface analysis based on the top gate structure has made little progress and lacks a reliable charge trap characterization model suitable for carbon tube devices. Quantitative extraction and analysis of the interface state are crucial for the integration of top-gate devices. Herein, a 5 nm thick Y2O3 thin film was selected as the gate dielectric layer in the top-gate CNTFETs device, and a post-annealing process in air ambience was utilized to optimize the Y2O3-CNT interface. A series of device performance evaluation results indicated that the post-annealing process in air ambience can effectively improve the on-state current and reduce the threshold voltage and subthreshold swing of the device, which are derived from diffusion of oxygen atom in the Y2O3 layer and optimization of the interface of Y2O3-CNT. Specifically, the maximum mobility, subthreshold swing, and threshold voltage are calculated to be 29 cm2/V s, 103 mV/dec, and −0.1 V, respectively, and the interface state density is reduced from 2.68 × 1012 to 1.51 × 1012 cm−2 in the gate insulator. These results not only are important to understand the dielectric impact on CNTFET devices but also are useful for future materials' development and device optimization for high-performance CNT-based electronics. [ABSTRACT FROM AUTHOR]

Recently, Ma et al. [Phys. Rev. Lett. 118, 027402 (2017)] have suggested that water molecules encapsulated in (6,5) single-wall carbon nanotube experience a temperature-induced quasiphase transition around 150 K interpreted as changes in the water dipoles orientation. We discuss further this temperature-driven quasiphase transition performing quantum chemical calculations and molecular dynamics simulations and, most importantly, suggesting a simple lattice model to reproduce the properties of the one-dimensional confined finite arrays of water molecules. The lattice model takes into account not only the short-range and long-range interactions but also the rotations in a narrow tube, and both ingredients provide an explanation for a temperature-driven orientational ordering of the water molecules, which persists within a relatively wide temperature range. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotube (SWCNT)-based membranes (pellicles) and gas counterflows are used as a debris mitigation system in extreme ultraviolet (EUV) lithography. Densification with volatile liquids is a well-known approach to tune the performance of SWCNT membranes. However, densification can change the gas permeability through SWCNT membranes, violating the circulation of buffer gas counterflows. In the present work, we investigate the Ar permeability through SWCNT membranes before and after densification with isopropyl alcohol in the pressure drop test. The effective diffusivity of Ar through pristine and densified SWCNT membranes is, respectively, calculated to be Deffpristine = 330 × 109 m2 s−1 and Deffdensified = 4 × 109 m2 s−1. We developed a probabilistic model of gas penetration through SWCNT membranes. On the basis of the experimental data, the probabilities of Ar atoms penetrating through pristine and densified SWCNT membranes are estimated to be 8% and 0.1%, respectively. Structural changes in SWCNT membranes after densification with scanning electron microscopy and the Brunauer–Emmett–Teller technique are demonstrated. The bulk density of SWCNT membranes, measured using x-ray reflectometry, is found to be 0.38 and 0.89 g/cm3 before and after densification, respectively. The temporal dynamic of isopropyl alcohol evaporation from the volume of SWCNT membranes is analyzed using Fourier-transform infrared spectroscopy (FTIR). Results obtained using EUV and FTIR spectroscopy show that isopropyl alcohol is present in the volume of the SWCNT membrane even after the membrane has been left in vacuum (P < 0.01 Pa) for 22 h. [ABSTRACT FROM AUTHOR]

Field electron emission cathodes were constructed from knitted fabrics comprised entirely of carbon nanotube (CNT) fibers. The fabrics consisted of a top layer array of ∼2 mm high looped structures and a bottom layer that was 1 mm thick with a flat underlying surface. Field emission (FE) experiments were performed on 25.4 mm diameter CNT fabric cathodes in both direct current (DC) and pulsed voltage (PV) modes, and the results were compared to those obtained from a CNT film cathode. The DC measurements were performed at a maximum voltage of 1.5 kV. The CNT fabric cathode emitted 20 mA, which was an 8× increase over the emission current from the CNT film cathode. The DC results were analyzed using the corrected form of the Fowler–Nordheim FE theory initially developed by Murphy and Good, which allows for the determination of the formal emission area and effective gap-field enhancement factor. The PV experiments resulted in Ampere level emission currents from both CNT fabric and CNT film cathodes. For a 25 kV, 500 ns voltage pulse, the CNT fabric cathode emitted 4 A, which was 2× more current than the CNT film cathode. Scanning electron microscopy imaging after PV testing revealed that the fibers remained intact after >5000 pulses. These results indicate that knitted CNT fabrics offer a promising approach for developing large area, conformable, robust FE cathodes for vacuum electronic devices. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although nerve conduits provide an effective treatment approach for nerve repair, traditional nerve conduits merely serve as mechanical channels in the repair process. The therapeutic effect still needs to be improved. Carbon nanomaterials have good physicochemical properties and hold great potential in fields such as electrochemistry and tissue engineering. Nerve conduits loaded with carbon nanomaterials, after appropriate functional modifications, are expected to further enhance the quality of nerve repair. OBJECTIVE: To review the recent research progress of carbon nanomaterial-loaded nerve conduits/scaffolds for peripheral nerve repair. METHODS: PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases were searched for the literature on the application of carbon nanomaterial catheters in peripheral nerve regeneration. English keywords were “carbon nanomaterials, carbon-based nanomaterials, nerve conduit, nerve guidance conduit, scaffold, nerve regeneration, peripheral nerve repair, peripheral nerve injury” and Chinese keywords were “carbon nanomaterials, carbon materials, graphene, carbon nanotubes, nerve conduits, nerve scaffolds, nerve repair, nerve regeneration, peripheral nerve injury”. Finally, 69 articles were selected for this review. RESULTS AND CONCLUSION: (1) Carbon nanomaterials primarily restore damaged neural bioelectric signal conduction by activating calcium ion channels and inducing intracellular calcium activity. The application of various nerve conduit design strategies has improved the effectiveness of nerve repair. (2) Successful intraneural vascularization is the prerequisite for repairing peripheral nerve injuries. Reactive oxygen species and reactive nitrogen species generated by carbon nanomaterials trigger subsequent signaling pathways that promote intraneural vascularization. (3) The ratio of M1 to M2 macrophages affects the repair of peripheral nerve injuries. Carbon nanomaterials promote the polarization of macrophages into the M2 phenotype, thereby exerting their anti-inflammatory and regenerative effects. (4) Some carbon nanomaterials may induce excessive generation of reactive oxygen species intracellularly, potentially exhibiting cytotoxicity detrimental to nerve repair. However, appropriate functional modifications can improve the adverse effects caused by carbon nanomaterials. (5) Although carbon nanomaterials can restore the microenvironment of peripheral nerve injuries and play a positive role in promoting peripheral nerve regeneration, their inherent cytotoxicity and unclear in vivo degradation pathways still pose challenges for clinical application. However, by employing methods such as functional modification, it is possible to enhance the biocompatibility of carbon nanomaterials. Modified carbon nanomaterials have promising prospects in the field of neural tissue engineering. [ABSTRACT FROM AUTHOR]

We report for the first time MoS2/CNT hybrid nanostructures for memristor applications on flexible and bio-degradable cellulose paper. In our approach, we varied two different weight percentages (10% and 20%) of CNT's in MoS2 to improve the MoS2 conductivity and investigate the memristor device characteristics. The device with 10% CNT shows a low V SET voltage of 2.5 V, which is comparatively small for planar devices geometries. The device exhibits a long data retention time and cyclic current–voltage stability of ∼104 s and 102 cycles, making it a potential candidate in flexible painted electronics. Along with good electrical performance, it also demonstrates a high mechanical stability for 1000 bending cycles. The conduction mechanism in the MoS2-CNT hybrid structure is corroborated by percolation and defect-induced filament formation. Additionally, the device displays synaptic plasticity performance, simulating potentiation and depression processes. Furthermore, such flexible and biodegradable cellulose-based paper electronics may pave the way to address the environmental pollution caused by electronic waste in the near future. [ABSTRACT FROM AUTHOR]

We present in this paper the stability of SWCNT hybrid systems with Py molecules. vdW type interactions are therefore the main interaction mechanism between encapsulated molecules and nanotubes, and the simplest model to describe these interactions is the Lennard-Jones potential. We have therefore performed energy minimization calculations on hybrid SWCNTs in a very wide range of diameters and of all chirality using the Lennard-Jones potential. The structure of the carbon nanotube is obtained from the winding of graphene on itself to form a hollow cylinder described by the pair of integers (n, m) entirely determining its structural characteristics, while the optimization of the geometry of the Py molecule is obtained by SIESTA using the exchange–correlation functional LDA. After minimisation, an approach that combines density functional theory, molecular mechanics, bond polarizability model, and spectral moment's method has been used to compute Raman spectra. Two types of vibration modes of SWCNTs attract our attention. Initially, the modifications of the modes of Py after encapsulation will be analyzed. In the following discussion, we examine how the vibrational properties of single-walled carbon nanotubes (SWCNTs) are affected by encapsulation, specifically in relation to the RBM and tangential modes. Our analysis of the Raman active modes supports the notion that the structural integrity of the SWCNTs remains intact and indicates the occurrence of a charge transfer between the Py molecules and SWCNTs. This charge transfer depends on the geometric position of Py in the SWCNT. [ABSTRACT FROM AUTHOR]

In this paper, a novel high-speed and energy-efficient 4–2 compressor cell is proposed using carbon nanotube field-effect transistors. The proposed compressor is realized efficiently based on NAND–NOR gates and multiplexers. To estimate the performance of the presented design, simulations are carried out using Synopsis HSPICE under different conditions. The results demonstrate the improvement of the proposed design compared to the best reference designs in terms of delay and energy consumption, by 20–26%, respectively. Also, the susceptibility of the proposed design against the process, voltage, temperature (PVT), and noise variations is examined. It is robust against PVT variations and high amplitude of noises compared with its counterpart. Further, embedding the proposed compressor in an 8 × 8-bit binary multiplier demonstrates that it has better speed and energy consumption with regard to its counterparts. [ABSTRACT FROM AUTHOR]

This article explores the functionalization of single-walled carbon nanotubes (SWCNTs) through covalent chemical transformations. The authors focus on the Prato reaction and the use of azomethine ylides as intermediates. They investigate different reaction conditions and heating methods to optimize the process. The study also examines the application of an iridium-supported catalyst for the reduction of acetophenone. The findings provide valuable insights into the potential applications of SWCNTs in electronics, biosensors, energy storage, and medicine. Additionally, the study discusses the use of imino esters for functionalizing SWCNTs and the successful preparation of a heterogeneous catalyst using the functionalized SWCNTs as a metal support. The catalyst showed high efficiency in catalyzing the Meerwein-Ponndorf-Verley reduction of acetophenone. The study also highlights the advantages of microwave-assisted heating and the potential industrial applications of the supported catalyst. [Extracted from the article]

In the present article, a closed-form solution is carried out for the vibration response of CNT/GPL/fiber/polymer hybrid composite macro/micro/nanoplates resting on elastic support. Multi-layered fiber/polymer hybrid plates with either functionally graded carbon nanotube reinforced composite (FG-CNTRC) material or functionally graded graphene platelets reinforced composite (FG-GPLRC) material are two different types of plate considered here. The distribution of reinforcing nanocomposites can be uniform or functionally graded through the plate layers. The governing vibration equations are developed in the framework of the nonlocal elasticity theory of Eringen and using the first-order shear deformation plate theory. In the analytical solution procedure, the partial differential equations of motion are simplified to a series of homogeneous ordinary differential equations using a displacement field for Levy-type of the boundary conditions. The general solution of the obtained equations is expressed in terms of exponential functions. Using that the displacements should satisfy the remaining boundary conditions, the vibrational frequencies are derived. Finally, the influences of different parameters including geometry and material properties such as nonlocal parameter, number and angle of layers, volume fraction, and type of distribution of reinforcing nanocomposites are investigated and discussed. Natural frequencies for various boundary conditions are illustrated. The numerical results illustrate that the effects of the nonlocal parameter on the frequency decrease when one of the boundaries is free, and these effects increase when one of the boundaries is clamped for both FG-CNTRC and FG-GPLRC plates. [ABSTRACT FROM AUTHOR]

The review article emphasizes the silver nanoparticles (AgNPs)/gold nanoparticles (AuNPs) decorated graphene oxide (GO)/functionalized carbon nanotubes (f-CNTs) hybrid nanofillers reinforced polyaniline (PANI) ternary nanocomposites due to their extraordinary properties and multifunctional applications as compare to the individual components. Conducting polymer nanocomposites are used in various applications due to the synergic effect that enhances various properties of the individual components. Owing to the elevated thermal, optical, sensing, and dielectric properties of the nanocomposites that revealed as an effective material, which can be employed for the application in energy storage devices like solar cells, batteries, supercapacitors, sensing of heavy metal ions, etc. [ABSTRACT FROM AUTHOR]