Application Of Carbon Nanotubes Research Articles

Carbon nanotube assisted highly selective separation of organic liquid mixtures

Carbon nanotubes (CNTs) are prominent candidates for the separation of various polar and non-polar liquid mixtures. Numerous studies report the application of CNTs for isolating the binary aqueous liquid mixtures, but very few demonstrate the separation of organic liquid mixtures. Here, we investigate the selective permeation of cosolvents such as ethanol, isopropanol, n-butanol, acetone, and tetrahydrofuran into the CNTs from the binary mixtures of benzene using molecular dynamics simulations. Our findings reveal that extremely small-sized (11,0) CNTs achieve almost 100% cosolvent capture selectivity in all five equimolar binary mixtures. In considerably bigger-sized CNTs such as (20,0), benzene accumulates inside along with the cosolvent, however, forms a well-distinguishable layer close to the interior wall of CNTs analogous to the second layer of a double-walled CNT. The results confirm that the liquid capture and selectivity are governed by the polarity and molecular size of the solvents as well as the CNT diameters.

Fabrication and application of CNT fiber-ultra-fine diamond composites via electrophoretic deposition and instantaneous Joule-heating method

One-dimensional carbon nanotube (CNT) fibers combined with three-dimensional ultra-fine diamond have a synergistic effect that can be used in a variety of applications. The current challenge is how to combine the two materials quickly and efficiently. To actualize the combination of the two materials, a two-step method is adopted in this study. The electrophoretic deposition method, which allows ultra-fine diamond particles to adhere uniformly and controllably to the surface of carbon nanotube fibers. The instantaneous Joule-heating method can realize the instantaneous high-temperature recombination of diamond and CNT fibers. CNT fibers' flexibility and thermal conductivity are combined with ultra-fine diamond's high hardness in this composite. A polishing tool was made by knitting ultra-fine diamond/CNT fiber threads on non-woven fabric and used to dry polish potassium dihydrogen phosphate (KDP) crystals. CNT fibers were examined for wear, surface morphology, and KDP surface roughness before and after processing. The results reveal that the composite material-prepared tool has greater wear resistance and machining efficiency.

(Digital Presentation) Carbon Nanotube Based Low-Reflective Coatings for Light Suppression

Space-borne instruments, such as seeker telescopes, optical sensors, etc., need to minimize stray and reflected light for facilitating space observatory missions. Durable low-reflectivity surfaces/coatings are thus required for suppressing unwanted light within these optical systems. The low-reflectivity coatings need to withstand harsh space environments, including UV radiation, atomic oxygen, vacuum, etc. The excellent mechanical, thermal, optical, and electrical properties of carbon nanotubes (CNTs) make them as ideal coating materials for obtaining low reflectivity surfaces for space applications. In this presentation, Faraday Technology Inc. will discuss an innovative electrophoretic deposition (EPD) manufacturing process, based on the use of pulsed electric fields, for controlled, reproducible, scalable application of low reflective CNT based coatings. The low-reflectivity CNT coatings have been successfully deposited on a variety of geometries: flat coupons, curved surfaces, sharp edges, and internal and external surface of square tubes using the FARADAYIC® EPD process with different anode-cathode configurations (Figure 1 A). The CNT coatings show the total hemispherical reflection of 0.5% - 1% across visible to near infrared (NIR) wavebands, which is much lower than the reflectance of the typically used Z306 black paint (Figure 1 B). Most importantly, the CNT coating shows minimal (~0.14-0.32%) reflectance increase after 5000 equivalent solar hours (ESH) UV/VUV illumination (Figure 1B). As a comparison, Z306 black paint shows ~2.40-4.05 % reflectance increases with same ESH UV/VUV illumination. Figure 1C indicates the CNT coatings has minimal 0-0.0015 (1/sr) BRDF increase in scatter. These CNT coatings also withstood simulated launch conditions vibrational tests, and demonstrated no weight loss and optical degradation. Furthermore, the CNT coatings were evaluated for atomic oxygen erosion resistance in a simulated low earth orbit (LEO) environment, and showed enhanced resilience when compared to Kapton and HOPG.In summary, a scalable manufacturing process for fabricating CNT based coatings with low reflectivity across visible to near infrared wavebands has been demonstrated and shown great potential in facilitating space observatory missions by minimizing stray and reflected light on targeted telescope and baffle materials and construction. The CNT based coatings can also be utilized as broadband absorbers for solar thermal power generation and storage, solar-driven steam generation for sanitization and water purification, and so on. Acknowledgements: The financial support of NASA SBIR program through contracts No. 80NNSC18P2062 & 80NSSC19C0177 is acknowledged. The authors acknowledge Alan Hopkins, Peter Fuqua, and Amber Hennessy from the Aerospace Corporation for simulated launch conditions vibration tests, optical characterization, and UV radiation effect tests. David Oakes and Daniel Hewett from Physical Sciences Inc. are acknowledged for the atomic oxygen erosion tests on the CNT based coatings. Figure 1

Carbon nanotubes in biomedical applications: current status, promises, and challenges

In the past decade, there has been phenomenal progress in the field of nanomaterials, especially in the area of carbon nanotubes (CNTs). In this review, we have elucidated a contemporary synopsis of properties, synthesis, functionalization, toxicity, and several potential biomedical applications of CNTs. Researchers have reported remarkable mechanical, electronic, and physical properties of CNTs which makes their applications so versatile. Functionalization of CNTs has been valuable in modifying their properties, expanding their applications, and reducing their toxicity. In recent years, the use of CNTs in biomedical applications has grown exponentially as they are utilized in the field of drug delivery, tissue engineering, biosensors, bioimaging, and cancer treatment. CNTs can increase the lifespan of drugs in humans and facilitate their delivery directly to the targeted cells; they are also highly efficient biocompatible biosensors and bioimaging agents. CNTs have also shown great results in detecting the SARS COVID-19 virus and in the field of cancer treatment and tissue engineering which is substantially required looking at the present conditions. The concerns about CNTs include cytotoxicity faced in in vivo biomedical applications and its high manufacturing cost are discussed in the review.Supplementary InformationThe online version contains supplementary material available at 10.1007/s42823-022-00364-4.

Efficient Green Synthesis of Highly Concentrated and Stable Carbon Nanotube Aqueous Dispersions for Photothermal Textile Fabrication

To maximize the performance of carbon nanotubes (CNTs) in photothermal conversion textiles, the green and efficient methods for the preparation of highly concentrated and stable aqueous dispersion of CNTs need to be urgently developed. Herein, the aqueous dispersion of CNTs with exceeding high concentration limits (over 100 mg/mL) is synthesized by an eco-friendly one-step hydrothermal method with the assistance of ionic liquid crystals (ILC). CNTs non-covalently wrapped by ILC can exist in various forms, such as well-dispersed dispersion, conductive slurry, thixotropic gel, and deformable dough. Particularly, the highly concentrated dispersion has excellent dispersion stability and remains stable even after 60 days of resting. Due to the cationic head group of ILC, the positively charged dispersion was electrostatically self-assembled to prepare photothermal textiles with excellent mechanical robustness and chemical stability, which can be applied to multiple harsh working conditions. This research shows an efficient and feasible method for the non-destructive dispersion of CNTs at high concentrations and also provides a reference for photothermal conversion applications of CNTs.

Progress on carbon nanotube filled polymer-based thermal conductive composites

<p indent="0mm">In the 5G era, the effective thermal management has become more demanding due to the ever-rising integration of electronic devices. High thermal conductivity materials play a crucial role in the field of thermal management, for example, thermal interface materials (TIMs) are used to fill the gap between the electronic chip and the heat sink to improve thermal transfer. In recent years, polymers have become a popular choice for thermal conductive materials because of their light, economical and excellent insulation and processability. To improve the thermal conductivity of materials, inorganic fillers with high thermal conductivity are generally composited with polymers. With the merits of high thermal conductivity, desirable chemical stability, carbon nanotubes (CNTs) are considered to have broad application potential in thermal conductive composites. Simple composition methods failed to increase thermal conductivity of composite materials to expected levels due to the large interfacial thermal resistance between CNTs and polymers and the disorderly distribution of CNTs in polymers. Therefore, reasonable design of polymer composites filled with CNTs is the key to achieving high thermal conductivity. This review mainly introduces the application of CNTs in thermal conductive polymer composites. Based on the existing theoretical research on thermal conductivity of composites and the application of molecular dynamics, more feasible strategies for improving the thermal conductivity of polymer composites filled with CNTs have been proposed. The approaches that improve the thermal conductivity of composites are mainly introduced from three aspects. (1) The intrinsic thermal conductivity of CNTs is an important factor affecting the thermal conductivity of polymer-based composites. CNTs and their macroscopic bulk materials both have excellent thermal conductivity. However, the thermal conductivity test results of the macroscopic materials of CNTs (such as CNTs fibers, arrays, and films) showed that the thermal conductivity of the macroscopic materials of CNTs was much smaller than that of single CNTs due to impurities, defects and inter-tube contact thermal resistance. Studies have shown that purification of CNTs and reduction of intertubular contact thermal resistance can improve the intrinsic thermal conductivity of CNTs. (2) From a microscopic perspective, phonons, the quantized energy of lattice vibration, are the main mechanism of heat conduction in most carbon fillers and polymers. Phonon scattering occurs in the process of phonon transfer, including the scattering between phonons and the scattering at the interface caused by defects and impurities, resulting in thermal resistance. The bonding strength of fillers and polymer interfaces are the crucial factors affecting the transmission of phonons. Hence, the thermal conductivity of composites could be effectively enhanced by surface treatment of CNTs, including covalent functionalization and non-covalent functionalization. Studies have shown that the functionalization can enhance the interfacial interaction between CNTs and polymers, while improving the dispersion of CNTs in polymers. (3) According to the thermal conduction network theory, the key to improving the thermal conductivity is whether the fillers can form a large number of continuous thermal conduction paths in the polymers and maintain a stable existence. However, high CNTs content usually affects the comprehensive properties of composites. To solve this problem, the arrangement and distribution of CNTs in the polymer should be improved to construct more heat conduction pathways, which can achieve high thermal conductivity at a low filling content. Here we introduce some effective methods, including the synergy effect, field orientation and the construction of 3D network structures. In this review, the characteristics and improvement effects of different technical approaches are summarized, which provides a reference for the research and application of CNT-filled polymer-based composites with high thermal conductivity. Finally, the future development prospects of carbon nanomaterial-filled polymer composites are discussed from perspectives of theoretical research, experimental design and engineering application.

In-materio computing in random networks of carbon nanotubes complexed with chemically dynamic molecules: a review

Abstract The need for highly energy-efficient information processing has sparked a new age of material-based computational devices. Among these, random networks (RNWs) of carbon nanotubes (CNTs) complexed with other materials have been extensively investigated owing to their extraordinary characteristics. However, the heterogeneity of CNT research has made it quite challenging to comprehend the necessary features of in-materio computing in a RNW of CNTs. Herein, we systematically tackle the topic by reviewing the progress of CNT applications, from the discovery of individual CNT conduction to their recent uses in neuromorphic and unconventional (reservoir) computing. This review catalogues the extraordinary abilities of random CNT networks and their complexes used to conduct nonlinear in-materio computing tasks as well as classification tasks that may replace current energy-inefficient systems.

Effect of Tube Diameters and Functional Groups on Adsorption and Suspension Behaviors of Carbon Nanotubes in Presence of Humic Acid

The adsorption and suspension behaviors of carbon nanotubes (CNTs) in the water environment determine the geochemical cycle and ecological risk of CNTs and the compounds attached to them. In this study, CNTs were selected as the research object, and the effect of tube diameters and functional groups (multiwall CNTs (MWNTs) and hydroxylated MWNTs (HMWNTs)) on the adsorption and suspension behaviors of the CNTs in the presence of humic acid (HA) was systematically analyzed. The results indicate that HA adsorption decreased with the increase in the solution pH, and the adsorption amount and rate were negatively correlated with the tube diameter of the CNTs. The surface hydroxylation of the CNTs prevented the adsorption of HA, and the maximum adsorption amounts on the MWNTs and HMWNTs were 195.95 and 74.74 mg g−1, respectively. HA had an important effect on the suspension of the CNTs, especially for the surface hydroxylation, and the suspension of the CNTs increased with the increase in the tube diameter. The characteristics of the CNTs prior to and after adsorbing HA were characterized by transmission electron microscopy, fluorescence spectroscopy, Fourier-transform infrared spectroscopy and Raman spectroscopy. The results indicate that surface hydroxylation of the CNTs increased the adsorption of aromatic compounds, and that the CNTs with a smaller diameter and a larger specific surface area had a disordered carbon accumulation microstructure and many defects, where the adsorption of part of the HA would cover the defects on the CNTs’ surface. Density functional theory (DFT) calculations demonstrated that HA was more easily adsorbed on the CNTs without surface hydroxylation. This investigation is helpful in providing a theoretical basis for the scientific management of the production and application of CNTs, and the scientific assessment of their geochemical cycle and ecological risk.

Plasma functionalization of carbon nanotubes and radical penetration mechanism

AbstractOwing to their superior properties, carbon nanotubes (CNTs) have attracted significant attention for various applications; however, their aggregation due to van der Waals forces hinders the industrial applications of CNTs. To overcome this problem, previous studies have proposed plasma functionalization, but its analysis is limited to the surface of thin‐film materials or involved small quantities of CNTs. In plasma functionalization, radicals need to penetrate from plasma into the CNTs to functionalize the entire CNTs. The radical penetration at all depths of CNTs is experimentally confirmed. The radical penetration mechanism with respect to thickness and free volume between CNTs is modeled using radical diffusion motion with the adoption of Knudsen diffusion.

Applications of Polymeric Membranes with Carbon Nanotubes: A Review.

Nanomaterials have been commonly employed to enhance the performance of polymeric membrane materials that are used in several industrial applications. Carbon nanotubes (CNTs) have gained notable attention over the years for use in membrane technology due to their anti-biofouling properties, salt rejection capability, exceptional electrical conductivity, and mechanical properties. This paper aims to discuss some of the recent applications of CNTs in membrane technology and their effect on a larger scale. The paper reviews successful case studies of incorporation of CNTs in membranes and their impact on water purification, desalination, gas separations, and energy storage, in an effort to provide a better understanding of their capabilities. Regarding the future trends of this technology, this review emphasizes improving the large-scale production processes and addressing environmental and health-related hazards of CNTs during production and usage.

Biomimetic approach to articular cartilage tissue engineering using carbon nanotube-coated and textured polydimethylsiloxane scaffolds.

There is a significant need to understand the complexity and heterogeneity of articular cartilage to develop more effective therapeutic strategies for diseases such as osteoarthritis. Here, we show that carbon nanotubes (CNTs) are excellent candidates as a material for synthetic scaffolds to support the growth of chondrocytes—the cells that produce and maintain cartilage. Chondrocyte morphology, proliferation, and alignment were investigated as nanoscale CNT networks were applied to macroscopically textured polydimethylsiloxane (PDMS) scaffolds. The application of CNTs to the surface of PDMS‐based scaffolds resulted in an up to 10‐fold increase in cell adherence and 240% increase in proliferation, which is attributable to increased nanoscale roughness and hydrophilicity. The introduction of macroscale features to PDMS induced alignment of chondrocytes, successfully mimicking the cell behavior observed in the superficial layer of cartilage. Raman spectroscopy was used as a noninvasive, label‐free method to monitor extracellular matrix production and chondrocyte phenotype. Chondrocytes on these scaffolds successfully produced collagen, glycosaminoglycan, and aggrecan. This study demonstrates that introducing physical features at different length scales allows for a high level of control over tissue scaffold design and, thus, cell behavior. Ultimately, these textured scaffolds can serve as platforms to improve the understanding of osteoarthritis and for early‐stage therapeutic testing.

Carbon Papers from Tall Goldenrod Cellulose Fibers and Carbon Nanotubes for Application as Electromagnetic Interference Shielding Materials.

To transform tall goldenrods, which are invasive alien plant that destroy the ecosystem of South Korea, into useful materials, cellulose fibers isolated from tall goldenrods are applied as EMI shielding materials in this study. The obtained cellulose fibers were blended with CNTs, which were used as additives, to improve the electrical conductivity. TGCF/CNT papers prepared using a facile paper manufacturing process with various weight percent ratios and thickness were carbonized at high temperatures and investigated as EMI shielding materials. The increase in the carbonization temperature, thickness, and CNT content enhanced the electrical conductivity and EMI SE of TGCF/CNT carbon papers. TGCF/CNT-15 papers, with approximately 4.5 mm of thickness, carbonized at 1300 °C exhibited the highest electrical conductivity of 6.35 S cm−1, indicating an EMI SE of approximately 62 dB at 1.6 GHz of the low frequency band. Additionally, the obtained TGCF/CNT carbon papers were flexible and could be bent and wound without breaking.

Developments and Applications of Carbon Nanotube Reinforced Cement-Based Composites as Functional Building Materials

Carbon nanotube (CNT) is a promising nanomaterial with excellent mechanical, electrical, thermal, and chemical stability. It has received extensive attention due to its unique multifunctional properties in engineering materials. Researchers have explored the preparation and characterization of CNT reinforced cement-based materials. Studies have shown that adding CNT will significantly improve the performance of cement-based materials. This article introduces the techniques for the dispersion characterization of CNT and summarizes the advantages and disadvantages of these techniques. The functionalized applications of CNT in cement-based materials are reviewed, including sensing performance, structural health monitoring of concrete, electromagnetic shielding, and other applications. In addition, the application and development prospects of CNT in 3D printing concrete have been prospected. Finally, we discussed the existing problems and challenges in developing and applying CNT in cement-based materials and suggested future research.

A Critical Review of Carbon Nanotube-Based Surface Coatings

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

Comparison between Janus-Base Nanotubes and Carbon Nanotubes: A Review on Synthesis, Physicochemical Properties, and Applications.

Research interest in nanoscale biomaterials has continued to grow in the past few decades, driving the need to form families of nanomaterials grouped by similar physical or chemical properties. Nanotubes have occupied a unique space in this field, primarily due to their high versatility in a wide range of biomedical applications. Although similar in morphology, members of this nanomaterial family widely differ in synthesis methods, mechanical and physiochemical properties, and therapeutic applications. As this field continues to develop, it is important to provide insight into novel biomaterial developments and their overall impact on current technology and therapeutics. In this review, we aim to characterize and compare two members of the nanotube family: carbon nanotubes (CNTs) and janus-base nanotubes (JBNts). While CNTs have been extensively studied for decades, JBNts provide a fresh perspective on many therapeutic modalities bound by the limitations of carbon-based nanomaterials. Herein, we characterize the morphology, synthesis, and applications of CNTs and JBNts to provide a comprehensive comparison between these nanomaterial technologies.

Nanostructured Carbons: Towards Soft-Bioelectronics, Biosensing and Theraputic Applications.

Recently, nanostructured carbon-based soft bioelectronics and biosensors have received tremendous attention due to their outstanding physical and chemical properties. The ultrahigh specific surface area, high flexibility, lightweight, high electrical conductivity, and biocompatibility of 1D and 2D nanocarbons, such as carbon nanotubes (CNT) and graphene, are advantageous for bioelectronics applications. These materials improve human life by delivering therapeutic advancements in gene, tumor, chemo, photothermal, immune, radio, and precision therapies. They are also utilized in biosensing platforms, including optical and electrochemical biosensors to detect cholesterol, glucose, pathogenic bacteria (e. g., coronavirus), and avian leucosis virus. This review summarizes the most recent advancements in bioelectronics and biosensors by exploiting the outstanding characteristics of nanocarbon materials. The synthesis and biocompatibility of nanocarbon materials are briefly discussed. In the following sections, applications of graphene and CNTs for different therapies and biosensing are elaborated. Finally, the key challenges and future perspectives of nanocarbon materials for biomedical applications are highlighted.

Raman Spectroscopy Characterization of Mineral Oil and Palm Oil with Added Multi-Walled Carbon Nanotube for Application in Oil-Filled Transformers

This century is experiencing a generation of nanotechnologies that makes use of the remarkable properties of nanofluids in applications such as electrical systems, industrialization, and others. In this paper, mineral oil (MO) and palm oil (PO), with multi-walled carbon nanotube (CNT), have been synthesized for use in oil-filled transformer applications. This research aims to use Raman characterization to assess the feasibility of CNT nanofluids samples at 0.02 g/L and 0.03 g/L concentrations. The chemical structure bonding that exists in the Raman band between 700 cm−1 and 3100 cm−1 regions is identified and analyzed, accordingly. After baseline removal and normalization, the precision band location and intensity of oil samples are fitted with a Gaussian profile. It was discovered that the peak at ~1440 cm−1 has the highest intensity for six oil samples, which is attributed to the (C–H) methylene scissors vibration of the CH2 group. Based on the FWHM profile and integrated area under the curve of PO, it was discovered that CNT contributes to the structural stability defect of PO. Principal component analysis (PCA) is also used in this study to classify different samples based on chemical composition and identify the spectral characteristics with the highest degree of variability.

Carbon nanotubes-based anode materials for potassium ion batteries: A review

Potassium ion batteries (KIBs) are appealing candidates for new rechargeable batteries for large-grid electrochemical energy storage systems due to their substantial reserves and low cost. However, due to the large ionic size of K+, anode materials for KIBs have slow K+ ion reaction kinetics, substantial volume expansions, and an unstable solid electrolyte interface film, all of which can have a significant impact on the electrochemical properties of KIBs anodes. To create feasible KIBs anodes it is important to optimize both structural and electrochemical performance, which requires pragmatic structural design based on relevant materials. Carbon nanotubes (CNTs) has been attractive materials in the investigation as anode materials for KIBs due to their unique structural, mechanical, and electrical capabilities. This work reports the applications of CNTs in KIBs with their future development as electrically conductive framework materials in KIBs anodes. Various synthesis methods for the preparation of CNTs-based anodes for KIBs are addressed, which has shown remarkable morphological and electrochemical performance. Recent studies have focused on developing unique nanoarchitectures for KIB anodes to boost their capacity and lifetime. Moreover, to determine the differences, the electrochemical performances of CNTs-based anodes for LIBs and NIBs are compared to that of CNTs-based anodes for KIBs.

Excellent heat transfer enhancement of CNT-metal interface by loading carbyne and metal nanowire into CNT

The carbon nanotube (CNT)-metal structure widely occurs in the CNT application, especially for the heat dissipation of electronic devices of various scales. However, the research on mechanism of interfacial heat transfer between CNT-metal lacks an accurate and complete research system, and the enhancement strategy of interfacial heat transfer lacks a systematic method. Therefore, in this work, CNT is in the end contact with metal substrate with four sizes of CNT and three types of metal. The interfacial thermal resistance of CNT-metal is calculated by the combination of Two Temperature Model and Molecular Dynamics, and its mechanism is analyzed by atomic vibration density of state, vibration overlap energy, interaction energy. In addition, carbyne and metal nanowire are loaded in the CNT to improve heat transfer and the variation of heat transfer as a function of the loading material length, structure size, type, movement and temperature are analyzed to reveal the enhancement strategy.

Current Understanding of Water Properties inside Carbon Nanotubes.

Confined water inside carbon nanotubes (CNTs) has attracted a lot of attention in recent years, amassing as a result a very large number of dedicated studies, both theoretical and experimental. This exceptional scientific interest can be understood in terms of the exotic properties of nanoconfined water, as well as the vast array of possible applications of CNTs in a wide range of fields stretching from geology to medicine and biology. This review presents an overreaching narrative of the properties of water in CNTs, based mostly on results from systematic nuclear magnetic resonance (NMR) and molecular dynamics (MD) studies, which together allow the untangling and explanation of many seemingly contradictory results present in the literature. Further, we identify still-debatable issues and open problems, as well as avenues for future studies, both theoretical and experimental.