Deposition Of Multi-walled Carbon Nanotubes Research Articles

Enhanced scaling resistance of superhydrophobic nanofibrous membrane for localized solar-heating distillation

In recent years, localized solar-heating distillation (LSD) has attracted more and more attention for its advantages of low energy consumption and low cost, which makes it a competitive alternative to traditional bulk-heating systems. However, salt scaling on the surface is still an urgent problem to be solved. In this work, superhydrophobic nanofibrous membrane was facilely prepared via deposition of multi-walled carbon nanotubes (MWCNTs) and subsequently coating of PDMS/SiO2, and used for scaling mitigation in LSD without feed/permeate circulation. The MWCNTs layer of the resultant membrane showed excellent light absorbance (97.98%) and photo-to-thermal (surface temperature of 57.3 ºC) capacities, while the PDMS/SiO2 layer repelled water droplet with water contact angles excessing 160º. LSD experiments demonstrated that the PDMS/SiO2- MWCNTs membrane achieved high evaporation rate (1.34 kg·m−2·h−1) and excellent photothermal conversion efficiency (90.7%) under one sun irradiation. Moreover, crystal nucleation and growth on membrane surface was dramatically suppressed due to the extra and protective air pockets provided by the superhydrophobic PDMS/SiO2 layer, which prolonged membrane lifespan from 10.0 h (for the PVDF control membrane) to 19.0 h (for M-1.1). These results evidenced that the superhydrophobic photothermal membrane can be taken as a potential candidate for stable LSD while making the best of renewable solar energy as the driving force.

Parameters controlling the electrokinetic deposition of multi-walled carbon nanotubes as biosensing thin films

Parameters controlling the electrokinetic deposition of multi-walled carbon nanotubes as biosensing thin films

Effect of orientation and nanoparticle addition of a encapsulated phase change material on heat transfer in a packed bed thermal energy storage system – A numerical analysis

Thermal energy storage technology research is growing globally due to the increased awareness of the clean energy demand and limitations of fossil fuel commodities. The packed bed latent heat thermal energy storage (PBLHTES) system is one among it promising a greater number of applications like solar water heating, industrial waste heat recovery process, thermal power generations, thermal comfort of buildings etc., Due to the high latent heat capacities, available in wide temperature ranges and minimal volume change, solid-to-liquid phase change materials (PCMs) are more attractive than any other latent heat materials to use in the PBLHTES system. Although, the low conductivity of PCM restricts the heat transfer while the charging and discharging periods. Therefore, it is necessary to incorporate thermal enhancement techniques in a PBLHTES system to improve the melting rate of the PCM. In this work, it is attempted to carry the 2-D numerical analysis of PBLHTES system provided with encapsulated PCM staggered in the flow direction of heat transfer fluid. The numerical results are validated with the experimental work. The effect of the inclination of PCM capsules with the flow direction (0°, 2.5°, 5°, 7.5°, and 10°), the addition of Multi-walled carbon nanotubes (MWCNT) nanoparticles (0 %, 1 %, 2 %, 3 %, 4 %, and 5 %) on energy absorbed by the PCM are studied. Also, the contours of temperature distribution and liquid fraction of the PCM with time are presented. The results revealed that the temperature distribution of HTF rises when PCM spheres orientated to the HTF shifted from 0 to 2.5° later it reduces. Though HTF temperature rises, the PCM temperature, liquid Fraction and energy absorbed decline when the capsules inclined to the flow direction. This is mainly due to the reason that the HTF moves outwards from the flow direction and towards the edges of the container, which makes the HTF carry a more amount of heat without sharing with the PCM capsules. Therefore, these arrangements will be helpful to switch over the ideal high-temperature HTF at the outlet without charging the TES system and vice versa. An improvement of 13.16 % melting rate is observed from 0 to 3 % of a nanoparticle addition and only 4 % enhancement is noted from 3 to 5 % MWCNT deposition. The effect of nanoparticles on energy absorbed by the PCM is nearly constant after 3 % of Multi-walled carbon nanotubes (MWCNT) addition. Therefore, this is the optimum MWCNT volume concentration to be added. The maximum energy absorbed with 3 % MWCNT for 60 min of time is 98.7 kJ and 97 kJ which are 3.5 % and 3.65 % more than the pure PCM for the standard case (0°) and 2.5° angle of attack of EPCMs with the flow direction.

Electrophoretic Deposition of Multi-Walled Carbon Nanotube Coatings on CoCrMo Alloy for Biomedical Applications.

Carbon nanotubes are a promising material for use in innovative biomedical solutions due to their unique chemical, mechanical, electrical, and magnetic properties. This work provides a method for the development of ultrasonically assisted electrophoretic deposition of multi-walled carbon nanotubes on a CoCrMo dental alloy. Functionalization of multi-walled carbon nanotubes was carried out by chemical oxidation in a mixture of nitric and sulfuric acids. The modified and unmodified multi-walled carbon nanotubes were anaphoretically deposited on the CoCrMo alloy in an aqueous solution. Chemical composition was studied by Fourier transform infrared spectroscopy. Surface morphology was examined by scanning electron microscopy. The mechanism and kinetics of the electrochemical corrosion of the obtained coatings in artificial saliva at 37 °C were determined using the open-circuit potential method, electrochemical impedance spectroscopy, and anodic polarization curves. The capacitive behavior and high corrosion resistance of the tested electrodes were revealed. It was found that the kinetics of electrochemical corrosion of the CoCrMo electrode significantly decreased in the presence of the functionalized multi-walled carbon nanotube coating. Electrophoretic deposition was shown to be an effective, low-cost, and fast method of producing nanotubes with controlled thickness, homogeneity, and packing density.

Electrophoretic Deposition (EPD) of Multi-Walled Carbon Nanotubes (Mwcnts) Onto Carbon Fiber (CF) Fabric

The Fiber Reinforced Polymer Composite (FRPC) has been widely employed in structural applications. However, adding nanoparticles such as multi-walled carbon nanotubes (MWCNTs) can be used to improve the composites' mechanical properties substantially. The purpose of this study is to investigate the stability of MWCNTs in distilled water (DW) and dimethylformamide (DMF). Electrophoretic deposition (EPD) was chosen as the method for depositing MWCNTs onto carbon fiber (CF) fabric because of the advantages of simple equipment and inexpensive cost. Thus, the effect of voltage and deposition time were examined to attain the ideal condition for the EPD of MWCNTs onto CF fabric. The stability of dispersed MWCNTs in various dispersing mediums was explored as the importance of the MWCNTs to remain stable in the medium is essential to achieve homogeneous deposition. The UV-Vis and colloidal stability test revealed that MWCNTs dispersed in DMF have greater stability than DW. Scanning Electrode Microscopy (SEM) images exhibited that 10 minutes and a 20 V voltage were the optimal conditions for the deposition of MWCNTs onto CF fabric.

Divalent cation contributions to the co-transport and deposition of functionalized multi-walled carbon nanotubes in porous media in the presence of bentonite or goethite nanoparticles: Experiment and simulation

This work investigates the influence of cation type (Ca2+ as compared to K+) on the co-transport and deposition of functionalized multi-walled carbon nanotubes (MWCNTs) with negatively (bentonite nanoparticles, BNPs) or positively (goethite nanoparticles, GNPs) charged natural nanoparticles under the same ionic strength (IS = 1 mM) conditions. In packed column tests with quartz sand (QS), the co-transport of MWCNTs was slightly increased by BNPs and inhibited by GNPs in both CaCl2 and KCl solutions, whereas the co-transport of BNPs or GNPs was facilitated by MWCNTs in both solutions. However, the co-transport of MWCNTs in the presence of BNPs or GNPs exhibited a different dependency on the cation type in quartz crystal microbalance with dissipation (QCM-D) tests. No deposition of MWCNTs and BNPs was observed in QCM-D studies in the presence of KCl, while enhanced deposition of MWCNTs and GNPs occurred in this same solution. In contrast, the deposition of both MWCNTs and BNPs or MWCNTs and GNPs increased in QCM-D in the presence of CaCl2. In both column and QCM-D studies, Ca2+ exhibited a more significant impact on co-transport than K+, especially for MWCNTs with GNPs than BNPs. Results from molecular dynamic simulations, aggregation studies, and interaction energy calculations indicate that non-DLVO interactions (e.g., H-bonding and cation-π interaction) between two nanoparticles (MWCNTs with BNPs or GNPs) played a non-negligible role in interpreting the deposition and co-transport in the presence of the divalent cation Ca2+. Mathematical modeling of breakthrough curves and retention profiles and aggregation results suggest that both straining and competitive blocking were enhanced and played dominant roles in the co-transport of MWCNTs in the presence of BNPs or GNPs in QS, especially in the presence of Ca2+. This work sheds novel insights on the contribution of divalent cations to interactions between two colloids and their co-transport in porous media. This information is needed to assess the environmental fate and risks of engineered nanoparticles (ENPs) and natural nanoparticles in aquatic and soil environments with abundant divalent cations.

Effect of natural convection hybrid nanofluid flow on the migration and deposition of MWCNT-Fe[formula omitted]O[formula omitted] in a square enclosure

In the present study, the migration and deposition of multi-walled carbon nanotube (MWCNT)-Fe3O4 nanocomposite particles in a square enclosure for natural convection hybrid nanofluid flow are analysed numerically using the Eulerian–Lagrangian model with one-way coupling. The governing equations are solved by the finite volume method and Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm. The location and velocity of 3000 selected composite particles in the host nanofluid are obtained by employing the Lagrangian approach. The influences of Rayleigh number and nanoparticle volume fraction on the thermal and flow behaviours of the system are presented. It is observed that the increasing volume fraction leads to a rise in the average Nusselt number at low Rayleigh numbers, while the case of ϕ=0.1% is the optimum volume fraction of nanoparticle in terms of heat transfer enhancement and strength of flow structure at Ra≥104. The simulations of Lagrangian particle tracking demonstrate that the minimum deposition rate of composite particles with dp=0.5 μm is obtained for a given Rayleigh number. The number of deposited large composite particles for the case of ϕ=0.1% is slightly more than for ϕ=0.3%, while the deposition rate of ultra-fine composite particles gets a higher value in the case of ϕ=0.3%. Moreover, the thermophoresis force plays a more significant role in small particle deposition than the Brownian random force.

Effect of pulse laser treatment at different process variables on mechanical behavior of carbon nanotubes electrophoretically deposited on titanium alloy

Purpose Titanium and its alloys are widely used as biomaterials for long-term implants, but they are usually surface-modified due to their weak bioactivity and wear resistance. Laser processing was used to modify the surface layer, and elemental carbon was a component of the deposited coatings. This research aims to use a combination of both methods based on preliminary electrophoretic deposition of multi-wall carbon nanotubes (MWNCTs) followed by pulse laser treatment. Carbon nanotubes were chosen due to their mechanical and chemical stability as well as their tubular shape, resulting in enhanced mechanical properties of laser-modified layers. Methods The pulse laser power and laser scanning speed were defined as variable process parameters. The microstructure, roughness Ra, nanohardness H, Young`s modulus E, and indent depth values were measured, and the H/E, H3/E2, and relative changes of all these values in comparison to MWCNTs-coated and non-coated surfaces, were calculated. Results The obtained results show that the best mechanical properties of MWCNTs-coated and laser-treated specimens are obtained at a laser power of 900 W and laser feed of 6 mm/s. The observed relations can be explained considering processes occurring on the surface such as deposition of carbon nanotubes, melting and re-crystallization of the surface layer, formation and possible partial decomposition of titanium carbides, and associated changes in local chemical composition, phase composition, and a level of residual stresses beneath the surface. Conclusions The developed process can substitute the time and money-consuming carbonization of titanium and its alloys.

Strain self-sensing capability of a tidal turbine blade fabricated of PU-foam/glass fiber/epoxy composites using MWCNTs

A novel marine composite structure (experimental tidal turbine blade) made up of a polyurethane (PU) foam/glass fiber/epoxy resin composite with multiwall carbon nanotubes (MWCNTs) is proposed herein to self-sense its strain under a structural test scenario. To achieve this, MWCNTs were deposited onto glass fiber fabric by spray-coating technique in order to form an effective electrical percolation network onto the external skin surface of the tidal turbine blade which enables piezoresistive capability. After MWCNT deposition, the blade was manufactured by means of one-shot resin transfer molding (RTM) in a closed and heated metallic mold specially designed with a blade geometry of 67 cm length. The results confirm that the spray coating technique is a viable method to deposit MWCNTs onto glass fiber surface and form electrical networks into the blade at a relatively low MWCNT concentration. Finite element analysis (FEA) predicted a suitable structural blade design with a maximum failure index value of 0.9 attained in the blade shear web. The measured longitudinal strains of the tidal turbine blade were in good agreement with the numerical strain values predicted with FEA. Electromechanical tests carried out on a structural test rig designed and instrumented for tidal turbine blades showed that the electrical resistance change response of carbon nanotube (CNT) network integrated into the blade was capable of following the mechanical curve response up to the blade limit load, confirming its ability to self-sense its strain in real time.

(Keynote) Bioelectrocatalytic Systems Based on Microcapsules, Glyconanoparticles and Microcavities

For four decades, the functionalization of electrodes by biomaterials based on electrogenerated polymers, carbon nanotubes and / or nano-objects, was widely used in the field of analytical chemistry and energy conversion. Recently, we redesigned enzymatic bioelectrodes in order to produce original objects. An innovative concept of reagentless biosensors based on enzymatic reduction of oxygen was developed by trapping and releasing the substrate of the enzyme (catechol) from the structure of the biosensor. A polyurethane support modified by two perforated microcapsules filled with catechol was easily transformed into a bioelectrode by the successive deposition of multiwalled carbon nanotubes and a mixture of laponite clay and tyrosinase enzyme [1].On the other hand, the development of glyconanoparticles resulting from the self-assembly of block copolymers composed of polystyrene and cyclodextrin as an inclusion site will be reported. These glyconanoparticles, which are stable in suspension in aqueous media, have an outer layer composed of cyclodextrin [2]. The latter allows a post-functionalization of the nanoparticle by hydrophobic molecules through host-guest interactions. It appears that it is possible to modulate the site density of βCD at the surface of the shell of the hybrid glyconanoparticles while maintaining its inclusion properties. Moreover, the anchoring of glyconanoparticles to the surface of electrodes has been carried out by host-guest interactions with electrogenerated polymers. The efficient immobilization of the nanoparticles allows the anchoring of multilayers of biotinylated glucose oxidase.Finally, a new generation of bioelectrodes for oxygen reduction and electrical energy production will be described. This approach is based on the design of flat electrodes made of permeable and conductive materials defining a very thin microcavity with a large surface area containing, in a microvolume, enzymes in powder form. The concept has been demonstrated with bilirubin oxidase (BOD) for the electroenzymatic reduction of oxygen in water. Besides the influence of the amount of enzyme trapped in the microcavity on the performance of the bioelectrode, the functionalization of the electrodes by adsorption of redox mediators or compounds allowing an orientation of the BOD favorable to electron transfer was also explored. After 5 months of storage in an aqueous buffer, the bioelectrode exhibits 20% of its initial electro-enzymatic activity. Y. Nedellec, C. Gondran, K. Gorgy, S. MC Murtry, O. El Mazria, P. Agostini, S. Cosnier. Biosens. Bioelectron., 180, 113137-113141(2021).M. Carrière, P. H. M. Buzzetti, K. Gorgy, M. Mumtaz, C. Travelet, R. Borsali, S. Cosnier. Nanomaterials 11 (2021) 1162. doi.org/10.3390/nano11051162.

Significance of Non-DLVO Interactions on the Co-Transport of Functionalized Multiwalled Carbon Nanotubes and Soil Nanoparticles in Porous Media.

Derjaguin-Landau-Verwey-Overbeek (DLVO) theory is typically used to quantify surface interactions between engineered nanoparticles (ENPs), soil nanoparticles (SNPs), and/or porous media, which are used to assess environmental risk and fate of ENPs. This study investigates the co-transport behavior of functionalized multiwalled carbon nanotubes (MWCNTs) with positively (goethite nanoparticles, GNPs) and negatively (bentonite nanoparticles, BNPs) charged SNPs in quartz sand (QS). The presence of BNPs increased the transport of MWCNTs, but GNPs inhibited the transport of MWCNTs. In addition, we, for the first time, observed that the transport of negatively (BNPs) and positively (GNPs) charged SNPs was facilitated by the presence of MWCNTs. Traditional mechanisms associated with competitive blocking, heteroaggregation, and classic DLVO calculations cannot explain such phenomena. Direct examination using batch experiments and Fourier transform infrared (FTIR) spectroscopy, asymmetric flow field flow fractionation (AF4) coupled to UV and inductively coupled plasma mass spectrometry (AF4-UV-ICP-MS), and molecular dynamics (MD) simulations demonstrated that MWCNTs-BNPs or MWCNT-GNPs complexes or aggregates can be formed during co-transport. Non-DLVO interactions (e.g., H-bonding and Lewis acid-base interaction) helped to explain observed MWCNT deposition, associations between MWCNTs and both SNPs (positively or negatively), and co-transport. This research sheds novel insight into the transport of MWCNTs and SNPs in porous media and suggests that (i) mutual effects between colloids (e.g., heteroaggregation, co-transport, and competitive blocking) need to be considered in natural soil; and (ii) non-DLVO interactions should be comprehensively considered when evaluating the environmental risk and fate of ENPs.

Enzyme immobilized multi-walled carbon nanotubes on paper-based biosensor fabricated via mask-less hydrophilic and hydrophobic microchannels for cholesterol detection

Despite the low cost of paper substrates, the lack of appropriate device fabrication techniques has hampered the overall efficacy of paper-based sensors. Addressing this issue, in this work, we develop a multi-walled carbon nanotube (MWCNTs) coated paper substrate-based biosensor using a novel method of wax deposition followed by vacuum filtration to design dedicated hydrophobic and hydrophilic channels for label-free, highly selective, and sensitive detection of cholesterol. Detailed morphological characterization studies reveal the uniform deposition of MWCNTs on the paper substrate (∼15–20 nm average diameter). Upon exposure to cholesterol, an excellent dynamic range of response over three orders of magnitude from 10 nM −75 µM and 100 µM–8 mM concentration range with a limit of detection of 3.2 nM (3 S/m) was obtained. The Michaelis–Menten constant (Km) was found to be 0.0093 µM. In addition, the fabricated biosensor exhibited excellent reproducibility, stability and high specificity to cholesterol with negligible response from interfering analytes. The excellent response of the fabricated biosensor can be attributed to the modulation of electrical properties due to electrostatic gating effect and direct electron transfer between MWCNTs and cholesterol due to the bioconjugation of Cholesterol oxidase (ChOx). The strategy employed here addresses some major challenges faced by the current methods of using rigid substrates and liquid electrolyte based analytical methods for detection of cholesterol. Furthermore, the sensor could successfully measure concentrations of cholesterol in saliva. This work provides a promising platform for developing low cost, interference free, disposable paper-based biosensors for point of care diagnostics.

Charge Manipulation Based Selective Functionalization of 3D Printed Structures for Functional Devices

AbstractAs a rapid prototyping technology, digital light processing (DLP)‐based 3D printing has prospect in electronics for its excellent molding speed and accuracy. Although complex and precise models can be obtained by the DLP‐based 3D printing, the functionalization of the printed models is still a challenge. Herein, a cost‐effective, efficient, and scalable approach based on the electrostatic interaction for the selective deposition of multiwalled carbon nanotubes (MWCNTs) on structures printed by DLP technique is reported. The structures are fabricated by alternatively DLP 3D printing of neutrally and positively charged resins, with positively charged resin for attracting MWCNTs with negative charges. The positive and negative charges come from the cationic groups incorporated into the polymer matrix and the anionic dispersant on the MWCNTs, respectively. By controlling the pH and concentration of the functional material dispersion, as well as the deposition time, the characteristics of the deposited functional materials, including thickness and conductivity, can be modulated. In addition, an all‐solid‐state supercapacitor is developed by this method, delivering a capacitance of 30 µF cm−2 and a good electrochemical stability.

Simple technique of multiwalled carbon nanotubes growth on aluminum foil for supercapacitors

A promising method for the direct growth of multiwalled carbon nanotubes (MWCNTs) on aluminum foil for supercapacitor electrodes has been developed. Mild oxidation of aluminum foil in a nickel nitrate solution was used to give catalytic properties to aluminum. After the treatment, the detected concentration of nickel in the surface layer of the aluminum foil was 20 wt%. Low-temperature deposition of MWCNTs was carried out by catalytic pyrolysis of ethanol vapor using liquid ethanol as the only precursor. The resulting MWCNTs layers had excellent adhesion to aluminum foil. A symmetrical two-electrode cell as well as a classical three-electrode cell, were used for electrochemical testing of the obtained materials. The cell with MWCNTs/Al foil electrodes exhibits the behavior of an electric double layer capacitor (EDLC). The specific capacity of the MWCNTs reaches 60F/g. This result is comparable to the characteristics of similar materials obtained by other methods. Excellent resistance to multiple charge–discharge cycles is also shown.

The role of the AC signal on the dielectrophoretic assembly of carbon nanotubes across indium tin oxide electrodes

Multi-walled carbon nanotubes (MWCNTs) can be aligned along electric field lines between transparent electrodes to form a conductive network. In this work, MWCNTs were successfully deposited across indium tin oxide (ITO) electrodes using dielectrophoretic (DEP) force. For the first time, the deposition of MWCNTs across ITO electrodes separated by a distance of 50 μm is demonstrated to form an aligned network. The role of the AC signal amplitude, frequency, and duration is investigated experimentally. We found that the alignment was improved as the frequency increases (>105 Hz), while the minimum amplitude per the unit distance to deposit MWCNTs across ITO electrodes was 0.2 V/μm. The deposition process is observed in real-time using optical microscopy, and the aligned MWCNTs are observed with FeSEM spectroscopy. The study also investigates the resistivity, density and length of the aligned MWCNTs as a function of time. The deposition of MWCNTs across transparent electrodes using a room temperature method that requires a simple setup has potential use in future transparent electronics.

Electrochemiluminescent immunoassay for the determination of CA15-3 and CA72-4 using graphene oxide nanocomposite modified with CdSe quantum dots and Ru(bpy)3 complex.

Anovel immunoassay is introducedbased on co-reactant enhancing strategy for the electrochemiluminescent (ECL) determination of CA15-3 and CA72-4 tumor markers in real samples. For the preparation of the signaling probe, CA15-3 and CA72-4 antibodies first were labeled using Ru(bpy)32+-N-hydroxysuccinimide ester (Ru(bpy)32+-NHS) and conjugated with L-cysteine capped cadmium selenide (CdSe) quantum dots. Finally, it was cross-linked with chitosan-grafted graphene oxide (GO@CS) nanocomposite. The capture probe was constructed by deposition of multi-walled carbon nanotubes (MWCNT) at the surface of dual-working gold screen-printed electrodes (MWCNT-dwSPE) and covalent attachment of capture CA15-3 and CA72-4 antibodies to MWCNT-dwSPE. ECL signals were recorded by applying cyclic potential ranging from 0.3 to 1.1 V (vs. pseudo-reference Ag/AgCl) at the scan rate of 100 mV.s-1. This immunoassay was used for determination of CA15-3 and CA72-4 in real samples the detection limits of 9.2 μU.ml-1 and 89 μU.ml-1 within linear ranges of 10 μU.ml-1-500 U.ml-1 and 100 μU.ml-1-150 U.ml-1, respectively. This immunoassay also showed acceptable accuracy with recoveries in the range 96.5-108 % and high reproducibility with RSD of 3.1 and 4.9.

Catalytic activity of K10 montmorillonite in the chemical vapor deposition of multi-wall carbon nanotubes from methane

The catalytic activity of K10 montmorillonite (K10Mt) as a substrate during the chemical vapor deposition (CVD) of carbon nanotubes (CNT) was investigated. The influence of free iron present in the structure of K10Mt during CNT synthesis was investigated. The synthesis was carried out both on samples containing free iron and after its chemical extraction. The structural and microstructural parameters of the samples were characterized by scanning electron microscopy with X-ray dispersion spectroscopy (SEM/EDS), energy dispersive transmission electron microscopy (TEM/EDS), X-ray fluorescence spectroscopy, X-ray diffraction (XRD), infrared spectroscopy (FTIR), and Raman spectroscopy, and X-ray photoelectron spectroscopy. It was found that K10Mt, before Fe removal, was covered with coarser forms of carbon with rounded shapes characteristic for pyrolytic carbon deposits, while after chemical purification the K10Mt particles were covered with regular forms of CNT. During the CVD process at 850 °C, multi-walled carbon nanotubes about 1 μm in length were formed on the surface of pure K10Mt. Under the conditions of synthesis, the K10-Mt/CNT nanocomposites were formed. After extraction of free iron from K10Mt, the most likely nucleation sites for CNT growth were Mg- and Fe-containing compounds structurally integrated with the K10Mt substrate, such as iron phosphides, magnesia, and magnesium aluminate.

Significant role of molybdenum promoted TiO2 catalysts for carbon nanotubes production and their polymer nanocomposites

Role of specific catalysts system is still a thrust area for the synthesis of carbon nanotubes. Titania-supported Fe and Co catalysts were prepared using the sol-gel and wet-impregnation method. These catalysts were used for the deposition of multiwalled carbon nanotubes (MWNTs) from xylene by the catalytic chemical vapour deposition (CCVD) technique at 800 °C. In the present work, the effect of the addition of molybdenum with monometallic catalyst had been investigated from the viewpoint of the growth of the carbon nanotubes (CNTs). The results showed that the presence of molybdenum in minor amount with Fe/Co-based catalysts can increase the amount of deposition of CNTs. CNTs-Epoxy resin composites were fabricated using prepared carbon nanotubes with a CNTs loading of 0.2 wt% and performed flexural testing measurement. These multi-components systems of titania and carbon nanotubes have a capacity to enhance many properties significantly for specific applications.

Manufacturing method of aramid fiber applied to wearable intelligent system

With wearable smart textiles playing an increasingly important role in people’s life, aramid fiber (AF) stands out among high-performance materials due to its outstanding flexibility, high strength, and impact resistance. However, its excellent insulation makes it unable to sense and respond to external stimuli, which seems to be a call to multiwalled carbon nanotubes (MWCNTs) with high conductivity. In this paper, the effect of MWCNTs in enhancing the electrical properties and interfacial strength of aramid fiber reinforced polymer (AFRP) composites was researched. Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved that the polydopamine (PDA) layer and MWCNTs were successfully grafted onto the surface of the AF. Scanning electron microscopy (SEM) showed that the distribution of MWCNTs on the fiber surface is quite uniform and dense. As a result, the adhesion of PDA is more conducive to the deposition of MWCNTs, compared with the pristine aramid fiber. The modified fiber AF-PDA-MWCNTs obtained a resistance on the order of 104 MΩ without reducing its mechanical properties (the tensile strength has obtained an increase of 10.59%). The composite material may also have good interface properties, with the interlaminar fracture toughness GI increased by 200.99%. After being endowed with electrical properties, aramid fibers have strong potential in wearable textiles due to their flexibility, high sensitivity to various deformations, and excellent safety protection performance.

Combined Pressure Sensor With Enhanced Dynamic Range Based on Thin Films of Nanotubes and Graphite Nanobelts

Herein, we demonstrate the prototype of a combined flexible pressure sensor based on ultrathin multiwall carbon nanotubes (MWCNTs) and graphite nanobelts (GNBs) films embedded in polydimethylsiloxane (PDMS). A simple and scalable modified Langmuir–Blodgett method was used for deposition of both MWCNT and GNB films. The use of two types of carbon nanostructures (nanotubes and GNBs) with distinctly different mechanical properties allowed obtaining enhanced dynamic range for pressure sensing. Short response time, good sensibility and flexibility, and low power consumption for enhanced pressure range make possible applications of the sensor for healthcare monitoring and as a component in the human–machine interfaces application.