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In the present study, a novel pH-sensitive nanocarrier was prepared by grafting chitosan/polyvinylpyrrolidone (CS/PVP) on the surface of single-walled carbon nanotubes (SWCNTs). Levofloxacin (LVX), an anti-bacterial model drug, was loaded onto the resulting nanocomposite. The as-prepared nanocomposite was characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) techniques. The adsorption procedure was investigated under different sorption conditions, such as solution pH, adsorbent dosage, initial drug concentration, contact time, and temperature. The experimental data were analyzed using both non-linear and linear forms of kinetic and isotherm models. Based on the sum of squares errors and coefficient of determination values, the non-linear forms of the pseudo-2nd-order kinetic model and Langmuir isotherm model provided the best fit to the experimental data. Adsorption thermodynamic showed an exothermic and spontaneous nature of the drug sorption on the surface of the nanoadsorbent. In-vitro drug release tests were studied in simulated gastric fluid (SGF; pH = 1.2) and intestinal fluid (SIF; pH = 7.4) at 37 °C. The pH-sensitive nanocarrier indicated sustained drug release over 36 h. Nearly 99.76% of the drug was released in simulated intestinal fluid at pH = 7.4 in 36 h and 22.72% was released in simulated gastric fluid at pH = 1.2 in 30 min. The drug release profiles were well-fitted by the Korsmeyer-Peppas kinetic model, and the release mechanism of the nanocarrier was related to non-Fickian transport. Furthermore, the antimicrobial efficacy of the fabricated nanomaterials was evaluated against Staphylococcus aureus (Gram-positive). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the nanoparticles were subsequently quantified. [ABSTRACT FROM AUTHOR]

Carbon nanotubes-based thermoelectric materials with high electrical conductivity (σ) and excellent mechanical properties have promising applications in flexible wearable devices. Two-dimensional transition metal sulfide MoS 2 has been used to enhance the thermoelectric properties of carbon nanotubes due to its high Seebeck coefficient (S). However, MoS 2 nanosheets are prone to agglomeration due to their high specific surface area, which causes lower doping efficiency. In this work, MoS 2 @GO hybrids are successfully fabricated using a hydrothermal in-situ growth method to anchor exfoliated MoS 2 on graphene oxide (GO) nanosheets, and MoS 2 @GO hybrids significantly enhance the interfacial interaction between MoS 2 and single-walled carbon nanotubes (SWCNT), improve the carrier mobility, lead to a simultaneous enhancement of the S and the σ. The maximum S value of MoS 2 @GO/SWCNT is 42.3 ± 0.2 μV K−1, the σ is 1173.2 ± 45.6 S cm−1, and an optimum power factor (PF) of 208.8 ± 8.5 μW m−1 K−2 is obtained at room temperature, which reaches 261.3 ± 10.2 μW m−1 K−2 at 385 K. For application demonstration, a thermoelectric device is assembled by connecting six pairs of p-type MoS 2 @GO/SWCNT and n-type copper sheets in series, which demonstrates an open-circuit voltage of 17.4 mV and an output power of 2.1 μW under a temperature difference of 50 K. Therefore, this study enriches the design and synthesis strategy of exfoliated MoS 2 and provides a new approach for the development of high-performance SWCNT-based thermoelectric materials, which has important potential applications in the field of wearable electronics. [ABSTRACT FROM AUTHOR]

Single-wall carbon nanotubes (SWCNTs) have unique electrical properties, making them potential silicon and copper replacements in semiconductors and nanointerconnects. Current research focuses on single vacancy defects, needing expansion to other topological defects. In this study, we account for the presence of topological defects and develop a model that demonstrates their impact on the electrical properties of carbon nanotubes (CNTs) by using a degradation coefficient for the conductivity. This study employs density functional theory combined with the nonequilibrium Green's function method to systematically analyze the influence of various topological defects on the electronic structure and transport characteristics of SWCNTs, using I–V curves, transmission spectra, and 3D transmission spectra. The results indicate that defects of the same type substantially degrade the electronic transport properties of CNTs, with the degree of degradation varying based on the defects' positions and quantities. This degradation can result in a reduction of over 20% in the electronic transport capacity compared with ideal CNTs. A linear positive correlation exists between the extent of degradation and the magnitude of the defects. Furthermore, the presence of a small number of 5–8–5 defects and Stone–Wales defects can induce bandgap opening from 0.109 to 0.549 eV for the bandgap of (6,6) CNTs. However, a high defect concentration reduces the bandgap, potentially to zero. Notably, regardless of whether the bandgap increases or decreases, the bandgap of (6,6) CNTs remains smaller than the bandgap of (11,0) semiconductor CNTs, leading to the transition of SWCNTs to metallic conductors. Finally, the differential conductivity diagram of CNTs with topological defects was analyzed, demonstrating that introducing specific 5–8–5 defects can effectively regulate the electrical properties of the CNTs. This paper analyzes the effects of defects on the CNTs electrical properties and finds a regulatory effect, providing a reference for carbon-based transistor manufacturing. [ABSTRACT FROM AUTHOR]

There has been significant interest in producing single‐walled carbon nanotubes (SWNTs) with specific chirality to ensure consistent and predictable performance. However, chirality‐selective growth has traditionally required low reaction temperatures, causing SWNTs with low graphitization degrees. In this work, a magnesia supported cobalt catalyst (Co/MgO) is introduced for chemical vapor deposition growth of SWNTs with a narrow chirality distribution even at a high temperature of 900 °C, which promotes enhanced graphitization of SWNT walls. The achievement is attributed to the strong metal‐support interactions that prevent catalyst particle sintering under harsh reaction conditions. The resulting SWNTs provide fundamental raw materials for high‐efficiency single‐chirality separation. Because of the relatively large chiral differences between the major species and their narrow chirality distribution, the study can readily isolate six distinct (n, m) SWNT types including (6, 5), (8, 3), (9, 2), (7, 5), (7, 6), and (8, 4), with purities exceeding 91% by gel chromatography. Compared with commercially HiPco‐ and CoMoCAT SG65i‐ SWNTs, the separation efficiency and yield are greatly improved. This work demonstrates the growth of high‐quality SWNTs with a narrow chirality distribution, paving the way toward their efficient single‐chirality separation. [ABSTRACT FROM AUTHOR]

There is an urgent need for new approaches to reduce the environmental impact of plastics. One approach is to enhance recyclability. Covalent adaptable networks (CANs), where crosslinks are chemically reversible, offer an attractive alternative to thermoset materials. Another option is to strengthen polymers using nanofillers, to reduce the amount of material needed. In this regard, single‐walled carbon nanotubes (SWNTs) are excellent candidates as fillers due to their extreme strength‐to‐weight ratio and dimensionality. Here, SWNTs functionalized as mechanically‐interlocked derivatives (MINTs) are shown to significantly improve the mechanical properties of polyimine (PI) CANs, with close to optimal efficiency. Enhancements in both stiffness and ultimate strength, approaching 100% load transfer considering the SWNT loading, are observed for PI MINT, while composites made with pristine SWNTs exhibit poor improvement. The PI MINT CANs can be recycled both thermally and chemically without compromising their mechanical properties. Finally, prototype carbon fiber PI MINT laminar composites are also fabricated and characterized, demonstrating a significant increase in their mechanical properties. [ABSTRACT FROM AUTHOR]

Controlling the redox states of single‐walled carbon nanotubes (SWNTs) is important for the optimization of their real performances in various fields. By means of in situ photoluminescence (PL) spectroelectrochemical measurements, we report a successful modulation for the redox parameters (redox potentials and electrochemical band gap) of (6,5) and (7,5)SWNTs with a simple change in conjugated polymers (CPs) non‐covalently wrapped on the nanotubes. The large shift in the band gap (187 meV for (6,5)SWNTs and 101 meV for (7,5)SWNTs) was connected to the prominent difference in the interactions between the CPs and SWNTs as suggested by molecular dynamics (MD) simulations, while a striking difference in the π‐electrons states of CP/SWNTs enabled the tuning of SWNTs’ electronic states. Asymmetrical modulation for the reduction potential (LUMO) and oxidation potential (HOMO) of the SWNTs was observed as well. Our results can be promising for a simple but precise control of the electric states of SWNTs. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) were synthesized by floating catalyst chemical vapor deposition (FCCVD) reactions. The complicated processing parameters that included a precursor solution composition, reaction temperature, flow rate of the carrier gas, weak oxidants, and injection rate of the precursor solution were controlled to synthesize single‐walled carbon nanotubes (SWCNTs) during the reaction process. The effects of the processing parameters were analyzed with respect to the formation of SWCNTs, yield, and the crystallinity in the CNTs structure. The SWCNTs were characterized by the Raman spectroscopy, scanning electron microscope, high‐resolution transmission electron microscopy, and thermogravimetric analysis. A high reaction temperature, high H2 flow rate, low injection rate of solution precursor, and low concentrations of iron catalysts in the reaction were important factors to improve the crystalline quality of the SWCNTs. The purity of the initial product grown by the standard process was more than 90 wt %, with a yield of 0.5 g/h. The average G/D ratio of the initial product was 178, and it had a distinct RBM peak. HRTEM confirmed that the synthesized SWCNTs had high purity and crystallinity. The SWCNTs could be tunable to meet a particular application by varying the reaction conditions. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWCNTs) with a narrow diameter distribution and high areal density hold great promise for a variety of applications, particularly in advanced electronics and biomedical devices. This study utilizes Mn ion doping as a strategic approach both to stabilize the ZrO 2 -supported Fe catalyst and regulate lattice oxygen release, thereby facilitating the growth of SWCNTs with high areal density and a narrow diameter distribution. The ZrO 2 -supported Fe catalyst was meticulously dispersed on Si/SiO 2 (300 nm) substrates through the optimization of spin-coating speed and solvent viscosity, aiming to enhance the dispersion and uniformity. Investigation into the precise control over the Mn ion content was conducted to regulate the structure and stability of the Mn-doped ZrO 2 -supported Fe catalyst. Mn ions perform a dual role: they maintain a higher proportion of ZrO 2 in the monoclinic phase, which in turn alleviates the monoclinic-tetragonal phase transition during chemical vapor deposition (CVD) growth. Concurrently, the conversion of Mn3+ to Mn4+ ions captures the lattice oxygen released during the formation of zirconium transition oxides. Additionally, first-principles simulations have confirmed the stabilizing impact of Mn ions on the catalyst, which reduces aggregation and maturation, ultimately resulting in a more concentrated diameter distribution of as-grown SWCNTs. This approach has successfully achieved the controlled growth of high areal density SWCNTs with a diameter distribution of 1.73 ± 0.08 nm. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, novel materials combining palladium‐imprinted polymers (PdIP) with single‐walled carbon nanotubes (SWCNTs) were developed to modify screen‐printed electrodes (SPEs) and tested as sensors for detecting palladium ions. The arrangement of the SWCNTs‐PdIP network is crucial for the electrochemical performance of the material. Therefore, we compared two types of materials: one with covalent linkages and the other with non‐covalent linkages between the SWCNTs and the polymer. The materials were characterized using Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy, and porosimetry. Cyclic and differential pulse voltammetry demonstrated a significant improvement in the electrochemical properties of the material with covalent linkages between PdIP and SWCNTs. The results confirmed the performance of the proposed SWCNTs‐X/PdIP‐based electrochemical sensor for detecting palladium ions. They showed a linear relationship in the concentration range of 0.06–1.5 mmol L−1, and the estimated limit of detection (LOD) was 0.026159 mmol L−1 (S/N=3). The constructed sensor showed high analytical sensitivity (675.46 μA mmol−1 L cm−2), good repeatability (RSD=4.05 %), and recovery (97 %). [ABSTRACT FROM AUTHOR]

Armchair graphene nanoribbons (AGNRs) known as semiconductors are holding promise for nanoelectronics applications and sparking increased research interest. Currently, synthesis of 5‐AGNRs with a quasi‐metallic gap has been achieved using perylene and its halogen‐containing derivatives as precursors via on‐surface synthesis on a metal substrate. However, challenges in controlling the polymerization and orientation between precursor molecules have led to side reactions and the formation of by‐products, posing a significant issue in purity. Here a precision synthesis of confined 5‐AGNRs using molecular‐designed precursors without halogens is proposed to address these challenges. Perylene and its dimer quaterrylene are utilized for filling into single‐walled carbon nanotubes (SWCNTs), following a precursor‐driven transition into 5‐AGNRs by heat‐induced polymerization and cyclodehydrogenation. SWCNTs restrict the alignment of confined quaterrylene enabling their polymerization with a head‐to‐tail arrangement, which results in the formation of pure 5‐AGNRs with three times higher yield than that of perylene, as the free rotation capability of perylene molecules inside SWCNTs lead to the formation of 5‐AGNRs concomitant with by‐products. This work provides a templated route for synthesizing desired GNRs based on molecular‐designed precursors and confined polymerization, bringing advantages for their applications in electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

In recent years, significant attention has been given to the physical properties of low-dimensional materials. Carbon nanotubes (CNTs), a prime example of such materials, are emerging as a promising next-generation candidate material for sensor components, including yoctogram (10-24 g) measurement devices and antennas capable of handling large-scale digital data. CNTs exhibit a variety of atomic arrangements due to their chirality. However, even 30 years after their discovery, controlling the chirality of CNTs remains challenging, and the specifics of their physical properties still require clarification. Understanding the vibration characteristics of carbon nanotubes (CNTs) is crucial for designing nanoscale structures and devices. In this study, we analyzed the effects of tube diameter, push ratio, and length of CNTs on vibration using molecular dynamics simulation. This method allows for the modeling of ideal geometric structures at the atomic level and the tracking of their behavior. The findings are as follows: For armchair carbon nanotubes, the resonance frequency decreased with an increase in the length of the CNTs. It was observed that the thermal energy generated during vibration tends to decrease with an increase in tube diameter. The full width at half maximum increases with an increase in the push ratio. [ABSTRACT FROM AUTHOR]

Abstract Small interfering RNAs (siRNA) technology has emerged as a promising therapeutic tool for human health conditions like cancer due to its ability to regulate gene silencing. Despite FDA-approved, their delivery remains localized and limiting their systemic use. This study used single-walled carbon nanotubes (SWNTs) functionalized with polyethylene glycolated (PEGylated) phospholipids (PL-PEG) derivatives for systemic siRNA delivery. We developed an siRNA systemic delivery vehicle (SWNT-siRNA) by conjugating SWNT functionalized with PL-PEG containing either amine (PA) or maleimide (MA). The functionalized SWNT with a lower molecular weight of PA produced the SWNT-siRNA conjugate system with the highest stability and high siRNA loading quantity. The system delivered siRNA to a panel of tumour cell lines of different organs (i.e. HeLa, H1299 and MCF-7) and a non-cancerous human embryonic kidney 293 cells (HEK293T) with high biocompatibility and low toxicity. The cellular uptake of SWNT-siRNA conjugates by epithelial cells was found to be energy dependent. Importantly, the presence of P-glycoprotein, a marker for drug resistance, did not inhibit SWNT-mediated siRNA delivery. Mouse xenograft model further confirmed the potential of SWNT-siRNA conjugates with a significant gene knock-down without signs of acute toxicity. These findings pave the way for potential gene therapy applications using SWNTs as delivery vehicles.

This study presents the results of a comprehensive investigation into the fabrication of single-walled carbon nanotubes (SWCNTs) employing chemical vapor deposition (CVD) technique, with nickel nanoparticles serving as crucial catalysts. These nanoparticles are synthesized via the reduction of oxide precursors using hydrogen and are strategically incorporated with ethanol vapor as the primary carbon source. The effectiveness and reproducibility of this synthesis method are thoroughly validated using advanced analytical techniques. Particularly noteworthy is the demonstrated ability to conduct the process at relatively low temperatures, not exceeding 500°C, which is of significant importance. Such precise control over synthesis conditions not only augurs well for the scalability of SWCNT production but also carries substantial implications for the advancement of nanomaterial synthesis methodologies.

Traditional deep fluorescence imaging has primarily focused on red‐shifting imaging wavelengths into the near‐infrared (NIR) windows or implementation of multi‐photon excitation approaches. Here, the advantages of NIR and multiphoton imaging are combined by developing a dual‐infrared two‐photon microscope that enables high‐resolution deep imaging in biological tissues. This study first computationally identifies that photon absorption, as opposed to scattering, is the primary contributor to signal attenuation. A NIR two‐photon microscope is constructed next with a 1640 nm femtosecond pulsed laser and a NIR PMT detector to image biological tissues labeled with fluorescent single‐walled carbon nanotubes (SWNTs). Spatial imaging resolutions are achieved close to the Abbe resolution limit and eliminate blur and background autofluorescence of biomolecules, 300 µm deep into brain slices and through the full 120 µm thickness of a Nicotiana benthamiana leaf. NIR‐II two‐photon microscopy can also measure tissue heterogeneity by quantifying how much the fluorescence power law function varies across tissues, a feature this study exploits to distinguish Huntington's Disease afflicted mouse brain tissues from wildtype. These results suggest dual‐infrared two‐photon microscopy can accomplish in‐tissue structural imaging and biochemical sensing with a minimal background, and with high spatial resolution, in optically opaque or highly autofluorescent biological tissues. [ABSTRACT FROM AUTHOR]

Ionic polymer–metal composites (IPMCs), as innovative soft smart polymers, can effectively convert electrical energy into mechanical energy through electrochemically induced ion migration, demonstrating significant potential in soft intelligent robotics. As the actuation characteristics of IPMC actuators are largely determined by the electrochemical kinetics within the electrodes, it is highly desired to fabricate tailored electrodes with excellent electrical conductivity and superior electrochemical characteristics to develop high-performance IPMC actuators. Taking inspiration from the distinctive structure of soybean roots, we propose the concept of developing a soybean root-style composite electrode consisting of single-walled carbon nanotubes, silver nanoparticles, and gold nanoparticles for IPMCs using a combination of spray coating and electroplating technologies. The developed electrodes have a unique hierarchical structure, low surface resistance (2.80 Ω/sq), and greatly enhanced electrochemical characteristics because of the redox reactions of silver nanoparticles during the actuation process, which would facilitate the ion migration and storage in actuation. Accordingly, the resulting IPMC actuator outputs excellent electromechanical work under 2 V voltage, including large peak-to-peak deformation (displacement 14.91 mm, strain 0.94%), high deformation rate (1.07 mm/s), wide frequency response (0.01–10 Hz), and high generated stress (3.67 MPa). The IPMC actuators can be used to construct flexible artificial fingers, enabling efficient grasping and transport of delicate flowers without causing any damage to their surfaces. This study provides insight into the design and optimization of composite electrode materials for advanced IPMC actuators with improved functional capabilities in various applications. [ABSTRACT FROM AUTHOR]

Inhibiting the aggregation of nanoparticles (NPs) to prepare catalysts with a uniform particle size is crucial to control the chirality of single-walled carbon nanotubes (SWCNTs). It has been proven that the quality of SWCNTs can be effectively improved through the use of FeMo NPs with small fractions of Mo. In this work, the nucleation mechanism of FeMo NPs, in which Mo atoms are gradually deposited on the solid-phase Fe55 seeds, is studied via classical molecular dynamics. The results demonstrate that the difference in cohesive energies between the components acts as a driving force for the transformation of FeMo NPs from the solid to the semiliquid phase. Furthermore, the lifetime of the alloy NPs in the semiliquid phase can be controlled by adjusting the Mo feeding rate. This study not only enables one to gain insight into the nucleation mechanism of FeMo NPs but also provides a strategy for restraining the structural fluctuation of NPs in the preparation of alloys with uniform particle size through adjusting the experimental parameters. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] Hydrogels derived from fluorenylmethoxycarbonyl (Fmoc)-conjugated amino acids and peptides demonstrate remarkable potential in biomedical applications, including drug delivery, tissue regeneration, and tissue engineering. These hydrogels can be injectable, offering a minimally invasive approach to hydrogel implantation. Given their potential for prolonged application, there is a need for non-destructive evaluation of their properties over extended periods. Thus, we introduce a hydrogel characterization platform employing single-walled carbon nanotubes (SWCNTs) as near-infrared (NIR) fluorescent probes. Our approach involves generating supramolecular self-assembling hydrogels from aromatic Fmoc-amino acids. Integrating SWCNTs into the hydrogels maintains their structural and mechanical properties, establishing SWCNTs as optical probes for hydrogels. We demonstrate that the SWCNT NIR-fluorescence changes during the gelation process correlate to rheological changes within the hydrogels. Additionally, single particle tracking of SWCNTs incorporated in the hydrogels provides insights into differences in hydrogel morphologies. Furthermore, the disassembly process of the hydrogels can be monitored through the SWCNT fluorescence modulation. The unique attribute of SWCNTs as non-photobleaching fluorescent sensors, emitting at the biologically transparent window, offers a non-destructive method for studying hydrogel dynamics over extended periods. This platform could be applied to a wide range of self-assembling hydrogels to advance our understanding and applications of supramolecular assembly technologies. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is a promising alternative to graphite anodes in battery materials. Therefore, it is critical to scrutinize their structural stability and charge storage capacity during battery operation. Herein, freestanding electrodes consisting of MoS2‐incorporated carbon nanotube aerogels are fabricated using a simple yet scalable hydrothermal method, as used in lithium‐ion batteries. The outer nitrogen‐doped graphitic carbon (NGr) layers support efficient charge transport, even under a substantial compressive environment, and improve the structural integrity, showing significant improvements in battery performance, such as a high rate capacity of 820 mAh g−1 at the current density of 5 A g−1 and 94% capacity retention after 170 cycles (1170 mAh g−1 at 1 A g−1 after 170 cycles), even in the absence of polymer binders and conductive additives. The resulting NGr/MoS2/single‐walled carbon nanotubes freestanding electrodes have great potential to increase the volumetric and gravimetric energy density of batteries. [ABSTRACT FROM AUTHOR]

The hybridization of single-walled carbon nanotubes (SWCNTs) and Cu nanoparticles offers a promising strategy for creating highly conductive and mechanically stable fillers for flexible printed electronics. In this study, we report the ultrafast synthesis of SWCNT/Cu hybrid nanostructures and the fabrication of flexible electrodes under ambient conditions through a laser-induced photo-thermal reaction. Thermal energy generated from the nonradiative relaxation of the π-plasmon resonance of SWCNTs was utilized to reduce the Cu-complex (known as a metal–organic decomposition ink) into Cu nanoparticles. We systematically investigated the effects of SWCNT concentration and output laser power on the structural and electrical properties of the SWCNT/Cu hybrid electrodes. The SWCNT/Cu electrodes achieved a minimum electrical resistivity of 46 μohm·cm, comparable to that of the metal-based printed electrodes. Mechanical bending tests demonstrated that the SWCNT/Cu electrodes were highly stable and durable, with no significant deformation observed even after 1000 bending cycles. Additionally, the electrodes showed rapid temperature increases and stable Joule heating performance, reaching temperatures of nearly 80 °C at an applied voltage of less than 3.5 V. [ABSTRACT FROM AUTHOR]

Carbon‐based nanomaterials have catalyzed breakthroughs across various scientific and engineering disciplines. The key to unlocking a new generation of tailor‐made nanomaterials based on single‐walled carbon nanotubes (SWCNTs) lies in the precise sorting of raw material into individual chiralities, each possessing unique properties. This can be achieved using conjugated polymer extraction (CPE), but to a very limited extent since the process generates only a few chirality‐enriched suspensions. Therefore, it is imperative to comprehend the mechanism of the wrapping of SWCNTs by polymers to unleash CPE's full potential. However, the lack of a diverse palette of chirality‐selective polymers with varying macromolecular parameters has hindered a comprehensive understanding of how the nature of the polymer affects the performance and selectivity of SWCNT isolation. To address this gap, multiple batches of such polymers are synthesized to elucidate the impact of molecular weight and dispersity on the purity and concentrations of the generated SWCNT suspensions. The obtained results explain the inconsistent outcomes reported in the literature, greatly improving the application potential of this promising SWCNT sorting approach. Concomitantly, the discovered significant influence of the macromolecular characteristics of conjugated polymers on the SWCNT isolation efficacy sheds considerable insight into the unresolved mechanism of this sorting technique. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Carbon nanotubes (CNTs) are considered an advanced form of carbon. They have superior characteristics in terms of mechanical and thermal properties compared to other available fibers and can be used in various applications, such as supercapacitors, sensors, and artificial muscles. The properties of single-walled carbon nanotubes (SWNTs) are significantly affected by geometric parameters such as chirality and aspect ratio, and testing conditions such as temperature and strain rate. In this study, the effects of geometric parameters and temperature on the mechanical properties of SWNTs were studied by molecular dynamics (MD) simulations using the Large-scaled Atomic/Molecular Massively Parallel Simulator (LAMMPS). Based on the second-generation reactive empirical bond order (REBO) potential, SWNTs of different diameters were tested in tension and compression under different strain rates and temperatures to understand their effects on the mechanical behavior of SWNTs. It was observed that the Young's modulus and the tensile strength decreases with increasing SWNT tube diameter. As the chiral angle increases, the tensile strength increases, while the Young's modulus decreases. The simulations were repeated at different temperatures of 300 K, 900 K, 1500 K, 2100 K and different strain rates of 1 × 10−3/ps, 0.75 × 10−3/ps, 0.5 × 10−3/ps, and 0.25 × 10−3/ps to investigate the effects of temperature and strain rate, respectively. The results show that the ultimate tensile strength of SWNTs increases with increasing strain rate. It is also seen that when SWNTs were stretched at higher temperatures, they failed at lower stresses and strains. The compressive behavior results indicate that SWNTs tend to buckle under lower stresses and strains than those under tensile stress. The simulation results were validated by and consistent with previous studies. The presented approach can be applied to investigate the properties of other advanced materials. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are used to prepare polymer composites with a high dielectric constant. However, a high leakage conductance is undesirable. Herein, amorphous carbon spheres were used to replace single-walled CNTs (SWCNTs) to fabricate polyvinyl chloride (PVC) composites. Two sets of composite films, marked with PVC/SWCNT and PVC/carbon sphere, were prepared. Dielectric, conductive and breakdown traits of composites were determined. PVC/carbon sphere composites display more advantageous properties than PVC/SWCNT composites. Unlike SWCNTs, carbon spheres exhibit a mild interface polarization with PVC and no percolation, resulting in balanced electric properties of composites including a rationally increased dielectric constant, greatly reduced dielectric loss and significantly improved breakdown strength. The optimal PVC composite with 12 wt% carbon spheres has a dielectric constant of ~ 186, dielectric loss of ~ 0.19 at 100 Hz, and breakdown strength of ~ 333 MV m−1. This work boosts a large-scale fabrication of outstanding composites used in modern capacitors. [ABSTRACT FROM AUTHOR]

One-dimensional carbon nanotube (CNT) exhibits excellent mechanical properties and is considered to be an ideal candidate material for the space elevator. However, subtle changes in its chirality strongly affect its physical and chemical properties, including mechanical properties (such as Young's modulus, YM). Theoretical studies reveal that the YMs of perfect single-walled carbon nanotubes (SWCNTs) are in the order of TPa and related to their structures. Nevertheless, due to the lack of SWCNTs samples with well-defined structures and the difficulties in mechanical tests on individual SWCNTs, the theoretical correlations between YM and structure of SWCNTs have not been verified and are still in debate, which directly influences the practical utilization of the excellent mechanical properties of SWCNTs. In this work, we have developed an experimental method to measure the YM of an individual micrometer-scale suspended CNT by atomic force microscopy. A distinct regularity is found between the YM and chirality (i.e., chiral angle and diameter) of SWCNT in the experiment for the first time. By comparing the YMs of SWCNTs with similar diameters and different chiral angles, it manifests that the SWCNT with a near zigzag configuration has a larger YM. This finding suggests that the effect of SWCNT's structures on the YMs cannot be ignored. The developed method of measuring YMs of SWCNTs will be valuable for further experimental research on the inherent physical and chemical properties of SWCNTs. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights Elephant trunk-inspired anisotropic wrinkling structures were formed on a sandwich-like conductive film through a controlled shrinking method. The wrinkled conductive network could withstand up to 200% tensile strain and exhibits a strain-enhanced electromagnetic interference shielding effectiveness when stretching parallel to the electric field polarization direction.

We have been working with carbon nanotube separation through host–guest chemistry. Herein, a new macrocyclic host molecule, Cu-tethered square nanobrackets, is designed, synthesized and applied to single-walled carbon nanotubes (SWNTs) for their diameter-based separation. The complexation between copper ions and dipyrrin moieties of the nanobracket gives Cu-tethered square nanobrackets, which is confirmed by absorption, Raman and MALDI-TOF mass spectra. Upon extraction of SWNTs with the nanobracket and copper(II), in situ-formed square Cu-nanobrackets are found to interlock SWNTs to disperse them in 2-propanol. The interlocking is confirmed by Raman spectroscopy after thorough washing of the extracted SWNTs. Pristine SWNTs were recovered through demetalation of the interlocked ones along with the nanobracket. Raman and absorption spectroscopies of the extracted SWNTs reveals the diameter enrichment of only several kinds of SWNTs in the diameter range from 0.94 to 1.10 nm among ≈20 kinds of SWNTs from 0.76 to 1.20 nm in their diameter range. The diameter selectivity is supported by the theoretical calculations with the GFN2-xTB method, indicating that the most preferred SWNT diameter for the square Cu-nanobrackets is 1.04 nm.

Single-walled carbon nanotubes (SWCNTs) present excellent electronic and mechanical properties desired in wearable and flexible devices. The preparation of SWCNT films is the first step for fabricating various devices. This work developed a scalable and feasible method to assemble SWCNT thin films on water surfaces based on Marangoni flow induced by surface tension gradient. The films possess a large area of 40 cm × 30 cm (extensible), a tunable thickness of 15∼150 nm, a high transparency of up to 96%, and a decent conductivity. They are ready to be directly transferred to various substrates, including flexible ones. Flexible strain sensors were fabricated with the films on flexible substrates. These sensors worked with high sensitivity and repeatability. By realizing multi-functional human motion sensing, including responding to voices, monitoring artery pulses, and detecting knuckle and muscle actions, the assembled SWCNT films demonstrated the potential for application in smart devices.

In recent decades, there has been a significant increase in the application of single‐molecule electrical analysis platforms in studying proteins and peptides. These advanced analysis methods have the potential for deep investigation of enzymatic working mechanisms and accurate monitoring of dynamic changes in protein configurations, which are often challenging to achieve in ensemble measurements. In this work, the prominent research progress in peptide and protein‐related studies are surveyed using electronic devices with single‐molecule/single‐event sensitivity, including single‐molecule junctions, single‐molecule field‐effect transistors, and nanopores. In particular, the successful commercial application of nanopores in DNA sequencing has made it one of the most promising techniques in protein sequencing at the single‐molecule level. From single peptides to protein complexes, the correlation between their electrical characteristics, structures, and biological functions is gradually being established. This enables to distinguish different molecular configurations of these biomacromolecules through real‐time electrical monitoring of their life activities, significantly improving the understanding of the mechanisms underlying various life processes. [ABSTRACT FROM AUTHOR]

In this study, the performance of a binder‐free LiNi0.6Co0.2Mn0.2O2 (NMC622) positive electrode utilizing single‐walled carbon nanotubes (SWCNTs) is investigated and compared to the conventional state‐of‐the‐art NMC622 composite positive electrode. The binder‐free electrode has been prepared without using toxic and expensive N‐Methyl‐2‐pyrrolidone (NMP) solvent and it is free‐standing that allows a wider range of applications such as flexible devices. Electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge reveal that the binder‐free positive electrode performance is similar to the conventional composite cathodes, deducing that only ≈1% of SWCNTs perform well not only as a conductive agent but also as a binder. The NMC622 composite electrode with SWCNTs provided specific capacity of 135.8 mAh g−1 at a 5C rate during discharge, with above 97% capacity retention after the rate capability test in a half cell. [ABSTRACT FROM AUTHOR]

The synthesis of gold nanoparticles reinforced functionalized single‐walled/multi‐walled carbon nanotubes nanohybrid based polyaniline nanocomposites were carried out using in situ polymerization. The chemical interaction and nanostructured morphology of the synthesized nanocomposites are studied using ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, x‐ray diffraction analysis, x‐ray photoelectron spectroscopy, and field emission scanning electron microscopy. Thermal stability of synthesized PANI/Au@f‐SWNTs is boosted by a magnitude of 30°C as compared with the pristine PANI matrix, which is attributed to a strong barrier effect because of the development of tortuous path that resulted from a uniform distribution of Au@f‐CNTs throughout the PANI matrix. For PANI/Au@f‐SWNTs, the AC conductivity and dielectric permittivity are improved by a value of 83.58 S/cm and 1.35 × 10−5 as well as the dielectric loss is reduced by a factor of 0.11 in comparison with the pure PANI matrix at an applied frequency of 106 Hz. PANI/Au@f‐SWNTs and PANI/Au@f‐MWNTs ternary nanocomposites exhibited excellent selectivity toward the hazardous Cr(VI) heavy metal ions in an aqueous medium with a limit of detection of 0.74 and 0.89 μM with a binding constant of 1.028 × 105 and 3.46 × 104 M−1, respectively, that can be selective and sensitive for the detection of Cr(VI) metal ions in water at trace level. [ABSTRACT FROM AUTHOR]

Excellent mechanical properties and outstanding optical and electrical properties of carbon nanotubes influence the fabrication of suitable devices and micro-electronic parts and systems, and they have been broadly applied in related fields. This paper aims to study the application of flexible high-stretch sensors of single-walled carbon nanotubes in human motion and attitude detection systems. In this paper, algorithm for human motion detection is proposed according to the content of human motion posture detection, and the properties of single-walled carbon tubing are analyzed in detail. The experimental results show that with the increase of carbon nanotube tubing, the reaction speed and sensitivity increase gradually. The reaction speed and sensitivity were 39% when the content was 1.5 wt%, 42% when the content was 2.0 wt%, and 59% when the content was 2.5 wt%. In summary, it can be found that within a certain range, the increase of carbon nanotube content can effectively reduce the hysteresis error of the sensor. It makes the sensitivity of the flexible high-stretch sensor higher, thereby improving the accuracy of the human motion attitude detection system. [ABSTRACT FROM AUTHOR]

This study presents the results of a comprehensive investigation into the fabrication of single-walled carbon nanotubes (SWCNTs) employing chemical vapor deposition (CVD) technique, with nickel nanoparticles serving as crucial catalysts. These nanoparticles are synthesized via the reduction of oxide precursors using hydrogen and are strategically incorporated with ethanol vapor as the primary carbon source. The effectiveness and reproducibility of this synthesis method are thoroughly validated using advanced analytical techniques. Particularly noteworthy is the demonstrated ability to conduct the process at relatively low temperatures, not exceeding 500°C, which is of significant importance. Such precise control over synthesis conditions not only augurs well for the scalability of SWCNT production but also carries substantial implications for the advancement of nanomaterial synthesis methodologies. [ABSTRACT FROM AUTHOR]

In this study, the combined effect of kaolinite with single-walled carbon nanotubes (SWCNTs) on mechanical, tribological, thermodynamic properties and structure of polymer composites based on polytetrafluoroethylene was investigated. Combination of SWCNTs with the composite mixture (containing kaolinite) was carried out in liquid and dry forms by ultrasonic dispersion. X-ray diffraction analysis revealed that the composite with 0.5 wt.% SWCNTs and 1 wt.% kaolinite in the liquid treatment was characterized by a 12% increase in the degree of crystallinity. It is shown that the introduction of complex fillers into PTFE significantly increased the wear resistance of composites by 688 times compared to the initial PTFE. Mechanical testing of the composites showed an increase in elastic modulus by 29% and 28% increase in compressive strength compared to the initial PTFE. The friction surface of the composites was investigated using IR spectroscopy and scanning electron microscopy. It was registered that the PCM friction surface is characterized by the formation of "scaly" structures. The IR spectra of PCM friction surfaces revealed the presence of hydroxyl groups and carboxylate anions – perfluorocarboxylic acid. It indicates the formation of a new structure on the friction surfaces of the composites with the formation of "scaly" micro-protrusions at increasing SWCNTs concentration. Keywords: polytetrafluoroethylene; single-walled carbon nanotubes; kaolinite; ultrasonic treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] Functionalized single-walled carbon nanotubes (SWCNTs) hold immense potential for diverse biomedical applications due to their biocompatibility and optical properties, including near-infrared fluorescence. Specifically, SWCNTs have been utilized to target cells as a vehicle for drug delivery and gene therapy, and as sensors for various intracellular biomarkers. While the main internalization route of SWCNTs into cells is endocytosis, methods for enhancing the cellular uptake of SWCNTs are of great importance. In this research, we demonstrate the use of a transfecting reagent for promoting cell internalization of functionalized SWCNTs. We explore different types of SWCNT functionalization, namely single-stranded DNA (ssDNA) or polyethylene glycol (PEG)-lipids, and two different cell types, embryonic kidney cells and adenocarcinoma cells. We show that internalizing PEGylated functionalized SWCNTs is enhanced in the presence of the transfecting reagent, where the effect is more pronounced for negatively charged PEG-lipid. However, ssDNA-SWCNTs tend to form aggregates in the presence of the transfecting reagent, rendering it unsuitable for promoting internalization. For all cases, cellular uptake is visualized by near-infrared fluorescence microscopy, showing that the SWCNTs are typically localized within the lysosome. Generally, cellular internalization was higher in the adenocarcinoma cells, thereby paving new avenues for drug delivery and sensing in malignant cells. [ABSTRACT FROM AUTHOR]

Although carbon nanotubes (CNTs) are promising candidates for gas-sensing materials owing to their high gas sensitivity and room-temperature operation, they suffer from poor selectivity to specific gas species. Noncovalent functionalization of CNTs with metal complex molecules is an effective and facile way to overcome this problem to enhance their sensitivity. This article reports on sensitive and selective gas sensors to ammonia (NH3) based on single-walled carbon nanotubes (SWNTs) interlocked with metal-tethered tetragonal nanobrackets (M-NBs, M = Cu-(II) and Co-(II)). The SWNT sensors with Cu- and Co-NBs showed 2.31 ± 0.11 and 2.24 ± 0.04%/ppm in sensitivities to NH3, which are more than 10 times higher than those of the pristine SWNT sensors prepared by removing M-NBs from the interlocked SWNTs. In addition, the detection limits of the SWNT sensors with Cu- and Co-NBs were estimated to be 16 ± 7 and 44 ± 5 ppb, respectively. Such high sensitivities are observed only for NH3, indicating that these sensors are highly selective for NH3 relative to other analyte gases/vapors (H2, CH4, ethanol, and acetone). The transfer characteristics of the field-effect transistor-type sensors and the binding energy to NH3 by density functional theory revealed that the metal ions of the M-NBs provided adsorption sites, resulting in greater charge transfer from NH3. This study suggests that both Cu- and Co-NBs stably and rigidly immobilized on the SWNT surface effectively enhance the sensitivity and selectivity of the gas sensors to NH3. [ABSTRACT FROM AUTHOR]

In this study, nanofibers obtained through the electrospinning process are explored for strain-sensing applications. Thermoplastic polyurethane (TPU) flexible structures were fabricated using the solution electrospinning process (SEP) technique. Subsequently, these structures were nanomodified with single-walled carbon nanotubes (SWCNTs) through immersion into an ultrasonicated suspension containing 0.3 wt% SWCNTs. The nanomodification aimed to impart an electrically conductive network to the structures. Micro-tensile tests and electrical resistance measurements were conducted to characterize the apparent mechanical and electrical properties, respectively. The fabricated structures demonstrated potential as wearable strain sensors for monitoring changes in strain across various applications. The samples exhibited excellent performance, high sensitivity, outstanding mechanical properties, and a broad stretching range. Scanning electron microscopy (SEM) observations provided qualitative insights into the activated conductive pathways during operation. [ABSTRACT FROM AUTHOR]

As power sources for Internet-of-Things sensors, thermoelectric generators must exhibit compactness, flexibility, and low manufacturing costs. Stretchable and flexible painted thermoelectric generators were fabricated on Japanese paper using inks with dispersed p- and n-type single-walled carbon nanotubes (SWCNTs). The p- and n-type SWCNT inks were dispersed using the anionic surfactant of sodium dodecylbenzene sulfonate and the cationic surfactant of dimethyldioctadecylammonium chloride, respectively. The bundle diameters of the p- and n-type SWCNT layers painted on Japanese paper differed significantly; however, the crystallinities of both types of layers were almost the same. The thermoelectric properties of both types of layers exhibited mostly the same values at 30 °C; however, the properties, particularly the electrical conductivity, of the n-type layer increased linearly, and of the p-type layer decreased as the temperature increased. The p- and n-type SWCNT inks were used to paint striped patterns on Japanese paper. By folding at the boundaries of the patterns, painted generators can shrink and expand, even on curved surfaces. The painted generator (length: 145 mm, height: 13 mm) exhibited an output voltage of 10.4 mV and a maximum power of 0.21 μW with a temperature difference of 64 K at 120 °C on the hot side. [ABSTRACT FROM AUTHOR]

The rapid growth of portable electronic devices, electric vehicles, and grid-scale energy storage systems has accelerated the demand for enhancing existing materials and innovating new materials in rechargeable battery technologies. Li-ion batteries have dominated the energy storage field among the various battery systems. Na-ion batteries have emerged as promising candidates due to their similarities to Li-ion battery chemistry, low cost, and environmental sustainability. This study explores the potential advantages of synthesizing the binder-free Cu 1.9 Bi 0.1 Se@SWCNT heterostructure directly on the copper collector surface. A crucial aspect of this research is the intentional use of nanostructuring during synthesis. This technique capitalizes on the benefits of greater surface area, enhanced electron transport, and superior ionic conductivity. The synthesis method not only ensures excellent electrical and mechanical contact with the collector but also omits the need for a binder, offering a potential for improved overall performance in Li-ion and Na-ion batteries. The electrodes were synthesized using a simple and cost-effective physical vapor deposition method. The structural, morphological, and electrochemical properties of the electrodes were characterized. The binder-free Cu 1.9 Bi 0.1 Se@SWCNT electrode with 25 % SWCNT content exhibits excellent performance in Li-ion half cells, maintaining a high energy capacity of 556 mAh g−1 at 0.1 A g−1 over 100 cycles and 244 mAh g−1 at 0.5 A g−1 over 750 cycles. However, in the Na-ion battery system, the performance is notably poorer, revealing challenges and limitations. Most likely, the larger size of sodium ions posed difficulties in intercalation within the anode material structure. [ABSTRACT FROM AUTHOR]