Carbon Nanotube Fibers Research Articles

Artificial Intelligence prediction and optimization of the mechanical strength of modified Natural Fibre/MWCNT polymer nanocomposite

Artificial Intelligence (AI), techniques like artificial neural networks (ANN), and machine learning have been used to solve a variety of engineering problems. In this study, Multiwall Carbon Nanotube (MWCNT) and Natural Fibres (NF) from plantain (Musa Paradisiaca) fiber (PF), were utilized to prepare a reinforced hybrid polymer nanocomposite for advanced composite applications. A chemical solution containing potassium permanganate (KMnO4) in acetone (C3H6O) was applied to modify the fibers to alter their surface and improve adhesion and interaction between the PF/polymer matrix. To predict and optimize the tensile strength (TS) of the prepared PF/MWCNT hybrid nanocomposite (PFMNC), the ANN model with hyper-parameter optimization in a single-layer-perceptron architecture of 3-5-1 was used with 5 neurons in the hidden layer, and Box-Behnken Design (BBD) was utilized. Scanning electron microscope (SEM) micrographs demonstrate that KMnO4 modification has impacted the TS of the hybridized nanocomposite. Mechanical Test results show that these variables impacted the TS of the PFMNC as shown by analysis of variance (ANOVA) with R2 = 0.9986. The expected findings were nearly identical to the experimental results. The model predicted an optimal tensile strength of 46.1563 Mpa. To substantiate the reliability of the empirical experimental investigation, TS analysis was performed at predicted optimal settings. TS results showed an average strength of 45.4401 Mpa. About 98.45 % of the projected tensile strength is accounted for by the model. The present study has demonstrated the effectiveness of the ANN-BBD modeling technique in achieving the appropriate mechanical property values quickly, reducing production costs, and preserving resources.

Biomedical Applications of CNT-Based Fibers.

Carbon nanotubes (CNTs) have been regarded as emerging materials in various applications. However, the range of biomedical applications is limited due to the aggregation and potential toxicity of powder-type CNTs. To overcome these issues, techniques to assemble them into various macroscopic structures, such as one-dimensional fibers, two-dimensional films, and three-dimensional aerogels, have been developed. Among them, carbon nanotube fiber (CNTF) is a one-dimensional aggregate of CNTs, which can be used to solve the potential toxicity problem of individual CNTs. Furthermore, since it has unique properties due to the one-dimensional nature of CNTs, CNTF has beneficial potential for biomedical applications. This review summarizes the biomedical applications using CNTF, such as the detection of biomolecules or signals for biosensors, strain sensors for wearable healthcare devices, and tissue engineering for regenerating human tissues. In addition, by considering the challenges and perspectives of CNTF for biomedical applications, the feasibility of CNTF in biomedical applications is discussed.

Development of Sugarcane Bagasse Ash Blended Cementitious Composites Reinforced with Carbon Nanotubes and Polypropylene Fibers

Cement-based composites, as primary construction materials, have undergone significant advancements over the years, yet researchers still face challenges in terms of their durability and impact on the environment. The goal of this research is to develop environmentally friendly cementitious composites blended with sugarcane bagasse ash (SCBA) and reinforce them with multi-walled carbon nanotubes and polypropylene (PP) fibers. Because of the high cost associated with carbon nanotubes (CNTs) and PP fibers, as well as CO2 emission, which affect the economic and environmental aspects of this field, an agricultural waste such as SCBA was introduced in the current study that is both economically and environmentally viable. For this purpose, five mixes were designed by varying the CNTs content whilst keeping the PP fibers and SCBA contents constant at 1.5% and 15% by weight of the binder (ordinary Portland cement + SCBA), respectively. The developed blends were tested for various mechanical and durability properties, i.e., compressive strength, flexural strength, impact strength, water absorption, and ultrasonic pulse velocity. Moreover, the microstructures of the newly developed low-carbon SCBA-based composites reinforced with PP fibers and CNTs were studied through scanning electron microscopy and energy dispersive spectroscopy. The results showed that the developed blends incorporating 15% SCBA, 1.5% PP fibers, and 0.08% CNTs, by weight of the binder, demonstrated the compressive, flexural, and impact strengths as 15.30 MPa, 0.98 MPa, and 0.11 MPa, respectively. The investigated blends proved to be cost-effective and environmentally beneficial, rendering them suitable for utilization in general construction and maintenance works.

Molecular-level network engineering of crosslinker towards high-performance carbon nanotube fiber

Intensive efforts are underway to integrate the distinct properties of individual carbon nanotubes (CNTs) into their assemblies and meet the growing demand for lightweight and strong materials. This study achieved CNT fibers (CNTFs) with high specific tensile strength (4.97 N/tex) and specific modulus (206.8 N/tex) by designing all-ring type bridges between CNTs. This reinforcement strategy involves suppressing the distortion of CNTs and promoting effective crosslinks within the fiber structure to increase the total inter-bundle interactions. The molecular-level network within the linking segment reduces vulnerability at the typically weak connection points and enhances load-transfer efficiency between crosslinked CNTs. In addition to improvements in mechanical properties, incorporating dopant groups in the bridge enhanced the electrical conductivity, reaching up to 2086 S m2/kg. This strategy provides straightforward access to multifunctional fibers beyond those of commercially accessible or literature-reported benchmark fibers.

Fabrication of carbon nanotube epoxy prepreg towards lightweight structural composites

Despite improvements in carbon nanotube fiber tenacities, their shear strength continues to limit their performance in composite applications. Shear strength can be improved through resin penetration into the nanotube fiber hierarchical microstructure to enhance internal interfaces. In this work, a manufacturing process uses an ionic liquid and epoxy to simultaneously stretch and infiltrate nanotube roving resulting in a nanotube-epoxy-ionic liquid prepreg. The ionic liquid also serves as a latent curing agent/hardener for the prepreg. After curing, the resulting composite fiber has comparable tenacity and specific modulus to fibers made without epoxy but with improved shear properties. The dry core shear failure mode typically observed in CNT fibers was eliminated and the apparent interfacial shear strength was improved by over an order of magnitude.

Pristine and Coated Carbon Nanotube Sheets—Characterization and Potential Applications

A carbon nanotube (CNT) sheet is a nonwoven fabric that is being evaluated for use in different textile applications. Several properties of pristine CNT sheets and CNT sheets coated with a polysilazane sealant and coating were measured and compared in the paper. The polysilazane coating is used to reduce the shedding of CNT fibers from the sheet when the sheet is in contact with surfaces. Most fabrics show some shedding of fibers during the washing or abrasion of the fabric. This study showed that the coating reduces the shedding of fibers from CNT fabric. The coating also increased the flame resistance of the fabric. The pristine and coated sheets both have low strength but high strain to failure. The pristine and coated CNT sheet densities are 0.48 g/cc and 0.65 g/cc, respectively. The pristine CNT sheet is approximately 27 μ thick. The coated sheet is approximately 24 μ thick. The coating may have densified the sheet, making it thinner. The thickness of the compliant sheets was difficult to measure and is a source of error in the properties. Characterization results are given in this paper. The results are for comparison purposes and not to establish material properties data. Possible applications for CNT sheets are briefly discussed.

Flexible electrochemical sensor for simultaneous determination of levodopa and uric acid based on carbon nanotube fibers

Levodopa (L-Dopa) is a widely prescribed drug for treating Parkinson's disease (PD), however, due to its motor complications, dosage management is required during clinical treatment. Uric acid (UA) is an important antioxidant in the body and is believed to have a defensive effect on the development and progression of PD. Therefore, accurate measurement of L-Dopa and UA in PD patients is of great significance. In this study, a flexible electrochemical sensor based on carbon nanotube (CNT) fibers was developed for individual and simultaneous determination of L-Dopa and UA. The electrochemical behavior and detection performance of the sensor were studied by cyclic voltammetry and differential pulse voltammetry. The CNT fibers (CNTF) electrode exhibited a wide detection range of 0.16–2.08 mM and 0.08–0.96 mM for L-Dopa and UA, as well as a high sensitivity of 0.7142 μA μM−1 cm−2 and 1.33 μA μM−1 cm−2, respectively. In addition, the sensor also exhibited good anti-interference, repeatability and bending stability, and has been successfully applied to the detection of L-Dopa and UA in bovine serum samples.

Continuous preparation of carbon nanotube fiber and its potential applications in electrical, thermal, mechanical and biosensing fields

Continuous preparation of carbon nanotube fiber and its potential applications in electrical, thermal, mechanical and biosensing fields

Theoretical Model for the Stress–Strain Curve of CNT-Reinforced Concrete under Uniaxial Compression

The incorporation of carbon nanotubes (CNTs) can enhance the mechanical properties of concrete. The stress–strain curves of CNT-reinforced concrete under uniaxial compression are investigated through an experimental program with different CNT and steel fiber proportions considered. The test results demonstrate that CNTs can increase both peak stress and peak strain, and steel fibers can further enhance the effect of CNTs. Additionally, steel fibers can effectively enhance both the strength and ductility. Theoretical models for the peak strain, initial elastic modulus, toughness index and relative absorbed energy are established. A theoretical model for the uniaxial compressive constitutive relationship of CNT-reinforced concrete considering CNT and steel fiber content is developed. Finite element (FE) modelling is developed to simulate the axial compression behavior of CNT-reinforced concrete.

Micro-mechanical interpretation of the non-linear tensile response of structured rods. Experiments on prototyped Gedankenmodelle with wavy sub-rods and application to Carbon NanoTube fibers

In order to demonstrate the wide range of inelastic non-linear tensile responses observed in structured fibers of various types, an ideal phenomenological model (Gedankenmodell) is theoretically analyzed, prototyped and tested. This consists in a rod made of a regular ensemble of sticks in a brickwork-like three-dimensional grid, hooped by elastic bands. The stick lateral faces are wavy surfaces in cohesive-frictional contact; their relative sliding induces a transversal expansion opposed by the bands, providing shear-slip constitutive laws that mimic the complex interaction forces in fibers composed of adherent fibrils. The macroscopic response of the rod to uniaxial loading is theoretically modeled in the framework of generalized standard materials. Experiments conducted on 3D-printed prototypes confirm the theoretical approach. As an example, the Gedankenmodell is applied to the tensile response of Carbon NanoTube (CNT) fibers, composed of CNTs laterally bonded via a spinning process. The model phenomenologically reproduces the tensile response of dry-spun, aerogel-spun and wet-spun CNT fibers, specifically the onset of a yield point, elastic unloading–reloading and inelastic aftereffects. This approach interprets the adhesion of the CNTs within the broad paradigm of cohesive-frictional adherence, combined with conservative forces of attraction.

Strengthening of carbon nanotube fiber using ecofriendly triblock copolymer and newly designed characterization via low-frequency noise

In this study, carbon nanotube fibers (CNTFs) were strengthened by densifying and reorienting CNT bundles using a triblock copolymer (poly (propylene glycol)–block-poly (ethylene glycol)–block-poly (propylene glycol (PPG–PEG–PPG)). This copolymer possesses a unique combination of hydrophilic and hydrophobic molecules, enabling it to easily penetrate and expand the distance between bundles. Through a stretching process after impregnation, the CNTFs induced a structural alignment of the bundles, resulting in high integration of the CNT bundles. The microstructural analysis of the fiber cross-section revealed an increased number of aligned CNTs along the fiber direction, concomitant with a reduction in the bundle-to-bundle distance owing to bundle aggregation. The highly aligned structure showed an average specific tensile strength of 0.536 N/tex and specific elastic modulus of 66.3 N/tex, which is an increase of 175 % and 252 %, respectively, compared to the pristine CNTF. The polymer infiltration stretching method effectively aggregated CNT bundles and removed macro voids within the CNTF. Additionally, the densification and alignment of CNTFs were characterized through novel low-frequency noise measurement and analysis. Understanding the nanoscale structure and morphology of CNTFs in nanoscale will provide valuable guidance for building enhanced strengthening strategies.

Nickel‐Foam‐ and Carbon‐Nanotubes‐Fiber‐Supported Bismuth Oxide/Nickel Oxide Composite; Highly Active and Stable Bifunctional Electrocatalysts for Water Splitting in Neutral and Alkaline Media

To increase the effectiveness of both the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER), significant efforts are made to produce bifunctional water‐splitting electrocatalysts. In this study, bismuth oxide/nickel oxide (Bi2O3/NiO)‐based composite is supported over the nickel foam (Bi2O3/NiO‐NF) and carbon nanotube fiber (Bi2O3/NiO‐CNTF) to develop two different electrode systems for water‐splitting studies. For OER, Bi2O3/NiO‐NF and Bi2O3/NiO‐CNTF require overpotential of 401 and 369 mV, respectively, to achieve the current density of 50 mA cm−2 in alkaline media, while the current density of 50 mA cm−2 is achieved at overpotential of 398 and 304 mV, respectively, in neutral media. For HER, Bi2O3/NiO‐NF and Bi2O3/NiO‐CNTF achieve the current density of 50 mA cm−2 at overpotential of 301 and 268 mV, respectively, in neutral media. For overall water splitting in neutral media, Bi2O3/NiO‐CNTF achieves the current density of 50 mA cm−2 at cell voltage of 1.654 V. The promising performance of synthesized electrocatalysts reveals that the mixed metal oxides (p‐block and d‐block elements)‐based electrocatalysts can be potential candidates for practical water splitting in basic (1 M KOH) as well as neutral media (1 M phosphate‐buffered saline).

Interface engineering for high-strength and high-ampacity of carbon nanotube/copper composite wires

Demands for lightweight and high strength electrical power transmission wires continue to rise, especially for electric vehicles, aerospace and 5G communication applications. Carbon nanotubes/copper composite wire is regarded as one of the promising candidate material systems for transmitting electricity and thermal energy. However, the improvements of the electrical conductivity and ampacity of CNT/Cu composite fiber often sacrifices the strength heavily. In this paper, a facile and robust approach including densification and Ni discontinuous nanoparticle layer (NiDPL) pre-seeding prior to Cu electroplating, was developed to enhance simultaneously the strength and ampacity of CNT/Cu composite fiber. Benefiting from the densification process, the conductivity and strength of CNT fiber were improved greatly. Further, NiDPL seeds formed using organic Ni salt (such as nickel acetate) were served as active sites for subsequent Cu layer deposition. The NiDPL were constructed on the surface of CNT fiber to improve both the chemical affinity and the electrons transfer between CNT and Cu. Finally, CNT/Cu composite wire with NiDPL achieved both high strength (2.54 GPa) and ampacity (1.68 × 106 A/cm2).

Constructing quasi-vertical carbon nanotubes fiber bridging on aluminum alloy with micro-channels to improve adhesive bonding with carbon fiber reinforced polymer composites

The poor wettability and compatibility, and weak mechanical interaction of bonding interface are main concerns for adhesive bonding of aluminum (Al) alloy and carbon fiber reinforced polymer (CFRP) composite, limiting its high strength developing and industrialization. In this study, the united treatments of anodizing, chemical vapor deposition (CVD) and resin pre-coating (RPC) were adopted to construct the quasi-vertically distributed carbon nanotube (CNT) fiber bridging for reinforcing the adhesive bonding joints. The results exhibited that better surface properties including morphology, roughness and wettability were obtained after anodizing. CNTs could be in-situ grown via the novel CVD method in the channels or micro-cavities formed by anodizing treatment. Acetone-diluted epoxy resin solution enabled to flow into the root of micro-cavities or the gap of growing CNT fibers to reduce potential void defects. Single lap shear test results indicated that Al-CFRP composites treated by anodizing, CVD and RPC performed up to 136.1 % increment in strength compared to the base. While the original debonding failure on Al alloy surface was changed into the complete delamination failure of CFRP composites, verifying the stronger bonding interface and strength. Thus, the novel united treatments were effective and might be an alternative solution in developing high-performance Al-CFRP composites.

Metal–Organic Framework-Derived NiS2 Nanoflowers Supported on Carbon Nanotube Fibers for Aqueous Rechargeable Nickel–Zinc Batteries

Metal–Organic Framework-Derived NiS₂ Nanoflowers Supported on Carbon Nanotube Fibers for Aqueous Rechargeable Nickel–Zinc Batteries

Single-wall carbon nanotube fiber non-woven fabrics with a high electrothermal heating response

Single-wall carbon nanotube fiber non-woven fabrics with a high electrothermal heating response

High-energy-density fiber-shaped aqueous Ni//Fe battery enabled by metal-organic framework derived spindle-like carbon incorporated iron disulfide

Metal dichalcogenides are regarded as encouraging electrode materials for aqueous rechargeable batteries on account of their excellent conductivity and theoretical capacity. Nevertheless, the structure's instability and low conductivity have restricted their development. Herein, MIL-101-Fe-derived spindle-like carbon incorporated FeS2 are successfully prepared exactly grown on carbon nanotube fibers (S–FeS2/CNTFs) with significantly enhanced conductivity and structure's stability due to the introducing of sulfur. Furthermore, we successfully constructed an outstanding-capacity fiber-shaped aqueous rechargeable (FAR) Ni//Fe batteries using the S–FeS2/CNTFs as advanced anodes. Density functional theory reveals that the S-doping significantly increase the conductivity and accomplish the structural reconstruction of the MIL-101-Fe. The S–FeS2/CNTF electrode exhibits a distinguished capacity of 0.55 mAh cm−2 at a current density of 6 mA cm−2, and maintains a capacity of 0.42 mAh cm−2 at a high current density of 200 mA cm−2, signifying outstanding rate performance. Notably, the as-assembled FAR Ni//Fe batteries achieve a phenomenal energy density of 137.5 mW h cm−3 at power density of 2200 mW cm−3. This approach affords an innovative opinion for developing outstanding-performance flexible aqueous energy-storage devices.

Flutter investigation and deep learning prediction of FG composite wing reinforced with carbon nanotube

Abstract The flutter of a composite wing reinforced with functionally graded carbon nanotubes (CNTs) has been investigated. A rectangular plate models a supersonic wing with cantilever boundary conditions. To determine displacement fields of a moderately thick plate, shear deformation theory is used. Using the Hamilton principle, a first-order piston theory was used to simulate supersonic airflow. This study examines four types of CNT thickness. Also, four different CNT distribution patterns are investigated. In a two-layer asymmetric composite, the effects of patch mass, mass distribution, fiber orientation angle, and distribution of CNTs were examined. Moreover, the results are compared and verified with other studies. A greater mass ratio led to a smaller flutter boundary, while a longer added mass increased the flutter boundary. A variation in the distribution pattern in CNT fiber orientation results in a distinct behavior of the flutter boundary for asymmetric composites with increasing orientation angles. The artificial neural network is utilized to predict the damping ratio, and the results showed great accuracy compared to the study results. Hyperparameter tuning is employed for better optimizing the predictive models.

Preparation Methods and Applications of Carbon Nanotubes and Carbon Nanotube Fibers

In recent years, carbon nanotubes have received widespread attention due to their unique structure and properties, making them applicable in various fields. This article discusses the excellent mechanical, optical, and electrical properties of carbon nanotubes and nanofibers. It then briefly introduces the preparation methods of carbon nanotubes and nanofibers, and finally summarizes the advantages and disadvantages of the preparation process. Research results indicate that the performance of carbon nanofibers is superior to that of carbon nanotubes. Due to their lightweight, flexibility, high conductivity and high surface area, carbon nanofibers play a significant role in the medical, chemical, and chip fields. However, the preparation process of carbon nanofibers is influenced by external environmental factors, resulting in poor performance and hindering research progress. This article aims to find a suitable preparation method to address the issue of poor performance of nanotubes and hopes to extensively apply carbon nanotubes and nanofibers in future developments.

A flexible precontact CNT-Al2O3 fiber sensor resistant to extreme temperatures.

As a new soft electronic product, a flexible precontact sensor provides spatial position sensing ability. However, the properties of traditional polymer materials change in industrial environments with extreme temperatures, which can cause the sensor function to decline or even fail. In this study, we propose a flexible fiber sensor based on the capacitor principle, which achieves a stable spatial positioning function and is not affected by a wide range of temperature changes. The fiber element of the sensor is obtained through the deposition of a flexible Al2O3 ceramic coating onto the surface of a carbon nanotube fiber (CNTF) via atomic layer deposition (ALD) technology. Coatings of different thicknesses (100 nm, 200 nm, and 300 nm) show different colors. The temperature resistance and flame retardancy of Al2O3 keep the morphology of the composite fiber unaffected by flame or high temperatures. Even at extreme temperatures (-78 °C to 500 °C), the sensor's sensing ability exhibits excellent stability. In addition, the spatial perception of the fibers remained viable after repeated bending (10 000 times). We demonstrate the potential of the sensor to acquire position information during high-temperature industrial pipe docking.