Carbon Nanotube Nanocomposites Research Articles

Electrochemical sensor based on carbon nanotube decorated with manganese oxide nanoparticles for naphthalene determination.

In this work, an electrochemical sensor was developed for the determination of naphthalene (NaP) in well water samples, based on a glass carbon electrode (GCE) modified as a nanocomposite of manganese oxides (MnOx) and COOH-functionalized multi-walled carbon nanotubes (MWCNT). The synthesis of MnOx nanoparticles was performed by the sol-gel method. The nanocomposite was obtained by mixing MnOx and MWCNT with the aid of ultrasound, followed by stirring for 24h. Surface modification facilitated the electron transfer process through the MnOx/MWCNT/GCE composite, which was used as an electrochemical sensor. The sensor and its material were characterized by cyclic voltammetry (CV), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Important parameters influencing electrochemical sensor performance (pH, composite ratios) were investigated and optimized. The MnOx/MWCNT/GCE sensor showed a wide linear range of 2.0-16.0μM, a detection limit of 0.5μM and a quantification limit of 1.8μM, in addition to satisfactory repeatability (RSD of 7.8%) and stability (900s) in the determination of NaP. The determination of NaP in a sample of water from a gas station well using the proposed sensor showed results with recovery between 98.1 and 103.3%. The results obtained suggest that the MnOx/MWCNT/GCE electrode has great potential for application in the detection of NaP in well water.

DFT calculation and experimental study of nitrogen-doped carbon nanotube nanocomposite in As+3 toxic ions removal

DFT calculation and experimental study of nitrogen-doped carbon nanotube nanocomposite in As+3 toxic ions removal

Effect of electron beam irradiation on thermal stability and crystallization behavior of flexible copolyester/multiwalled carbon nanotubes nanocomposites

AbstractPoly(butylene adipate‐co‐terephthalate) (PBAT), a biodegradable copolyester, was used as the polymer matrix to prepare nanocomposites with multiwalled carbon nanotubes (MWCNT) by melt‐mixing followed by hot‐pressing. The PBAT/MWCNT nanocomposites were exposed to electron beam (EB) irradiation, and thermal stability, melting and crystallization behavior of irradiated and unirradiated nanocomposites were comparatively investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. TGA results reveal increased thermal stability (up to 17°C) and maximum degradation temperature (Tmax) (up to 15°C) of PBAT/MWCNT nanocomposites, attributed to the high thermal stability of MWCNT and good MWCNT–PBAT interfacial interactions. However, the activation energy for thermal degradation (Ea) decreased with the presence of MWCNT in comparison to neat PBAT regardless of the MWCNT concentration. Both the thermal stability and Tmax of irradiated nanocomposites decreased by 3°C despite the crosslinking which can be attributed to successive minor irradiation‐induced polymer degradation, while Ea remained unchanged. Declined melting temperature (Tm), enthalpy of crystallization, enthalpy of melting and crystallinity of nanocomposites with the presence of MWCNT suggest the formation of less perfect crystals. Meanwhile, their increased glass transition temperature (Tg) and crystallization temperature (Tc) are due to the increased rigidity of PBAT chains and a reduced crystallization process in the presence of MWCNT, respectively. Similarly, reduced crystallinity and values of Tm and Tc of EB‐irradiated nanocomposites by 4.1%, 9.6%, and 7.5%, respectively, signifying the presence of PBAT‐crosslinks resulting in crystal defects.

Phase Morphology and Conductive Properties of PBT/POE-g-GMA/PP/CNT Nanocomposites with a Tri-Continuous Structure via Thermal Annealing

In order to improve the conductivity of polymer composites and elucidate the relationship between the microstructure and conductivity, a series of PBT/POE-g-GMA/PP/CNT nanocomposites with a tri-continuous structure and low conductive percolation threshold were prepared by melt blending. Compared to PBT/PP/CNT composites, the PBT/POE-g-GMA/PP/CNT nanocomposites show better conductivity owing to the selective distribution of carbon nanotubes (CNTs) in the POE-g-GMA phase with the same CNT content. The increasing content of the CNTs and POE-g-GMA refines phase morphology, thus influencing the CNTs’ conductive path. Composites containing 10 wt % POE-g-GMA display the lowest conductive percolation threshold at 1.0 phr. In addition, the influencing mechanism of thermal annealing on microstructure and conductivity was methodically investigated. Thermal annealing can effectively enhance the rebuilding of CNT conductive networks and continuity of the POE-g-GMA phase on the premise of the original phase structure, decreasing the volume resistivity of nanocomposites. The nanocomposites obtained in this study possess excellent electrical properties alongside the potential to be a candidate material in fields of sensors, electromagnetic interference shielding, and so forth.

Effects of Orientation and Dispersion on Electrical Conductivity and Mechanical Properties of Carbon Nanotube/Polypropylene Composite.

The orientation and dispersion of nanoparticles can greatly influence the conductivity and mechanical properties of nanocomposites. In this study, the Polypropylene/ Carbon Nanotubes (PP/CNTs) nanocomposites were produced using three different molding methods, i.e., compression molding (CM), conventional injection molding (IM), and interval injection molding (IntM). Various CNTs content and shear conditions give CNTs different dispersion and orientation states. Then, three electrical percolation thresholds (4 wt.% CM, 6 wt.% IM, and 9 wt.% IntM) were obtained by various CNTs dispersion and orientations. Agglomerate dispersion (Adis), agglomerate orientation (Aori), and molecular orientation (Mori) are used to quantify the CNTs dispersion and orientation degree. IntM uses high shear to break the agglomerates and promote the Aori, Mori, and Adis. Large Aori and Mori can create a path along the flow direction, which lead to an electrical anisotropy of nearly six orders of magnitude in the flow and transverse direction. On the other hand, when CM and IM samples already build the conductive network, IntM can triple the Adis and destroy the network. Moreover, mechanical properties are also been discussed, such as the increase in tensile strength with Aori and Mori but showing independence with Adis. This paper proves that the high dispersion of CNTs agglomerate goes against forming a conductivity network. At the same time, the increased orientation of CNTs causes the electric current to flow only in the orientation direction. It helps to prepare PP/CNTs nanocomposites on demand by understanding the influence of CNTs dispersion and orientation on mechanical and electrical properties.

Fabrication and characterization of Trans‐1,4‐polyisoprene/carbon nanotubes nanocomposites with thermo‐ and electro‐active shape memory effects

AbstractTrans‐1,4‐polyisoprene/single wall carbon nanotubes nanocomposites (TPI/SWCNT) nanocomposites with thermo‐ and electro‐active shape memory performance were prepared via solution blending and vulcanization. Herein, the mechanical, thermo‐mechanical, electric conductivity properties, thermo‐ and electro‐active shape memory properties of pure TPI and TPI/SWCNT nanocomposites were investigated. It was demonstrated that the addition of SWCNT into the TPI matrix can improve its crystallinity, crystallization temperature and storage modulus characteristics, and form a two‐crystal melting peak. Compared with the pure TPI, the TPI/SWCNT nanocomposites need more time to recover to their initial shape under thermo stimulus, and the recovery ratio of TPI/SWCNT nanocomposites with 2.5 wt% SWCNT was about 92%. Moreover, pure TPI and TPI/SWCNT nanocomposites with SWCNT content of up to 2.0 wt% under 30 V could not recover under electro stimulus, but the TPI/SWCNT nanocomposites with 2.5 wt% SWCNT displayed electro‐active shape recovery property with a recovery ratio of 87.5%, because a certain amount of SWCNT can provide joule heat to melt the crystals completely and unfreeze cross‐linking network of TPI.

Enhancement of dielectric and electro-optical characteristics of liquid crystalline material 4'-octyl-4-cyano-biphenyl with dispersed functionalized and nonfunctionalized multiwalled carbon nanotubes.

For recent applications, liquid crystal-carbon nanotube based nanocomposite systems have been proven to be highly attractive. In this paper, we give a thorough analysis of a nanocomposite system made of both functionalized and nonfunctionalized multiwalled carbon nanotubes that are disseminated in a 4'-octyl-4-cyano-biphenyl liquid crystal medium. Thermodynamic study reveals a decrease in the nanocomposites' transition temperatures. In contrast to nonfunctionalized multiwalled carbon nanotube dispersed systems, the enthalpy of functionalized multiwalled carbon nanotube dispersed systems has increased. In comparison to the pure sample, the dispersed nanocomposites have a smaller optical band gap. A rise in the longitudinal component of permittivity and, consequently, the dielectric anisotropy of the dispersed nanocomposites has been observed by dielectric studies. When compared to the pure sample, the conductivity of both dispersed nanocomposite materials has increased by two orders of magnitude. For the system with dispersed functionalized multiwalled carbon nanotubes, the threshold voltage, splay elastic constant, and rotational viscosity all decreased. For the dispersed nanocomposite of nonfunctionalized multiwalled carbon nanotubes, the value of the threshold voltage is somewhat decreased but the rotational viscosity and splay elastic constant both are enhanced. These findings show the applicability of the liquid crystal nanocomposites for display and electro-optical systems with appropriate tuning of the parameters.

Nanoantibiotic effect of carbon-based nanocomposites: epicentric on graphene, carbon nanotubes and fullerene composites: a review.

Carbon in many different forms especially, Graphene, Carbon nanotubes (CNTs), and Fullerene is emerging as an important material in the areas of the biomedical field for various applications. This review comprehensively describes the nano antibiotic effect of carbon-based nanocomposites: epicenter on graphene, carbon nanotubes, and fullerene Composites. It summarises the studies conducted to evaluate their antimicrobial applications as they can disrupt the cell membrane of bacteria resulting in cell death. The initial section gives a glimpse of both "Gram"-positive and negative bacteria, which have been affected by Graphene, CNTs, and Fullerene-based nanocomposites. These bacteria include Staphylococcus Aureus, Bacillus Thuringiensis, Enterococcus faecalis, Enterococcus faecium, Bacillus subtilis, Escherichia coli, Klebseilla pneumoniae, Pseudomonas aeroginosa, Pseudomonas syringae , Shigella flexneri,Candida Albicans, Mucor. Another section is dedicated to the insight of Graphene, and its types such as Graphene Oxide (GO), Reduced graphene oxide (rGO), Graphene Nanoplatelets (GNPs), Graphene Nanoribbons (GNRs), and Graphene Quantum Dots (GQDs). Insight into CNT, including both the types SWCNT and MWCNT, studied, followed by understanding fullerene is also reported. Another section is dedicated to the antibacterial mechanism of Graphene, CNT, and Fullerene-based nanocomposites. Further, an additional section is dedicated to a comprehensive review of the antibacterial characteristics of Graphene, CNT, and nanocomposites based on fullerene. Future perspectives and recommendations have also been highlighted in the last section.

PPy/SWCNTs-Modified Microelectrode Array for Learning and Memory Model Construction through Electrical Stimulation and Detection of In Vitro Hippocampal Neuronal Network.

The learning and memory functions of the brain remain unclear, which are in urgent need for the detection of both a single cell signal with high spatiotemporal resolution and network activities with high throughput. Here, an in vitro microelectrode array (MEA) was fabricated and further modified with polypyrrole/carboxylated single-walled carbon nanotubes (PPy/SWCNTs) nanocomposites as the interface between biological and electronic systems. The deposition of the nanocomposites significantly improved the performance of microelectrodes including low impedance (60.3 ± 28.8 k Ω), small phase delay (-32.8 ± 4.4°), and good biocompatibility. Then the modified MEA was used to apply learning training and test on hippocampal neuronal network cultured for 21 days through electrical stimulation, and multichannel electrophysiological signals were recorded simultaneously. During the process of learning training, the stimulus/response ratio of the hippocampal learning population gradually increased and the response time gradually decreased. After training, the mean spikes in burst, number of bursts, and mean burst duration increased by 53%, 191%, and 52%, respectively, and the correlation of neurons in the network was significantly enhanced from 0.45 ± 0.002 to 0.78 ± 0.002. In addition, the neuronal network basically retained these characteristics for at least 5 h. These results indicated that we have successfully constructed a learning and memory model of hippocampal neurons on the in vitro MEA, contributing to understanding learning and memory based on synaptic plasticity. The proposed PPy/SWCNTs-modified in vitro MEA will provide a promising platform for the exploration of learning and memory mechanism and their applications in vitro.

Corrosion, mechanical and microstructural properties of aluminum 7075—carbon nanotube nanocomposites for robots in corrosive environments

Corrosion, mechanical and microstructural properties of aluminum 7075—carbon nanotube nanocomposites for robots in corrosive environments

Nanocomposite of copper oxide nanoparticles and multi-walled carbon nanotubes as a solid contact of a copper-sensitive ion-selective electrode: intermediate layer or membrane component–comparative studies

In this paper, ion-selective electrodes sensitive to copper(II) ions are presented, in which new composite, synthesized from copper(II) oxide nanoparticles (CuONPs) and multi-walled carbon nanotubes (MWCNTs), was used as a solid contact. For comparison, electrodes obtained using separate components of the nanocomposite, i.e., CuONPs and MWCNTs, as well as unmodified electrodes, were also studied. The tested nanomaterials have been applied in two ways: as an intermediate layer placed between the ion-sensitive membrane and the internal electrode, and as an additional component of the ion-selective membrane mixture. To investigate the influence of the electrode’s structure modification, the selected analytical parameters obtained by potentiometric measurements (slope, linearity range, detection limit, potential stability, and reversibility) and electrochemical impedance spectroscopy measurements (membrane resistance and charge transfer resistance as well as double layer capacitance) were determined and compared. It was found that the use of all nanomaterials improves the properties of the electrodes, with the effect being the strongest for electrodes modified with the CuO-MWCNTs nanocomposite. The nanocomposite-based electrodes, both those with an intermediate layer and those with a nanocomposite-modified membrane, showed a Nernstian slope of the characteristic, a wider working range and a lower detection limit compared to unmodified electrodes. Moreover, application of all nanomaterials, especially nanocomposite resulted in improvement of both, stability and reversibility of the sensor potential. Modification of the electrodes did not make them sensitive to changing external measurement conditions (lighting, presence of gasses, redox potential). The electrode with the best parameters (based on nanocomposite) was successfully used to determine the Cu2+ ions content in tap water and mineral water, obtaining satisfactory results.

Novel electrochemical sensing platform basing on di-functional stimuli-responsive imprinted polymers for simultaneous extraction and determination of metronidazole

A novel magnetic-controlled electrochemical sensor has been fabricated by combined photo-responsive surface molecular imprinted polymers (P-SMIPs) and electrochemical sensor. In particular, the P-SMIPs were obtained by living radical polymerization of photo-responsive functional monomer onto the magnetic Fe3O4 modified multi-walled carbon nanotubes nanocomposites. The magnetic glassy carbon electrode was introduced to make the anchoring and removal of P-SMIPs onto the magnetic-controlled glassy carbon electrode easy to manipulate. Driven by UV/vis light, the platform performs releasing and absorption of metronidazole basing on conformational variations of the photo-responsive monomer at the receptor sites part in the P-SMIPs. This process can be tested by the photo-responsive variations of metronidazole electrochemical signal. As the consequence, extracting of P-SMIPs sensor can be conveniently triggered by the controllable UV light intervention measure, leading to effectively improve in both analytes mass transfer rate to the receiving media and extraction efficiency. The experimental result indicated that the excellent recoveries of metronidazole were varied between 77.9% and 89.9% with RSDs ≤4.87% in the biological samples. Therefore, the P-SMIPs sensor shows satisfactory potential in reusable extractions that can be recycled several times with no significant loss of activity, and this utilization strategy can be extended to other analytes, achieving manifold applications of pharmaceutical and environmental.

Microstructural Characterization of Al/CNTs Nanocomposites after Cold Rolling.

The deformation behaviour of aluminium reinforced by carbon nanotubes (Al/CNTs) nanocomposites during cold rolling was investigated in this work. Deformation processes after production by conventional powder metallurgy routes may be an efficient approach to improve the microstructure and mechanical properties by decreasing the porosity. Metal matrix nanocomposites have enormous potential to produce advanced components, mainly in the mobility industry, with powder metallurgy being one of the most reported production processes. For this reason, it is increasingly important to study the deformation behaviour of nanocomposites. In this context, nanocomposites were produced via powder metallurgy. Advanced characterization techniques carried out the microstructural characterization of the as-received powders and produced nanocomposites. The microstructural characterization of the as-received powders and produced nanocomposites was carried out through optical microscopy (OM), and scanning and transmission electron microscopy (SEM and TEM), complemented by electron backscattered diffraction (EBSD). The powder metallurgy route followed by cold rolling is reliable for Al/CNTs nanocomposites. The microstructural characterization shows that the nanocomposites exhibit a different crystallographic orientation than the Al matrix. CNTs in the matrix influence grain rotation during sintering and deformation. Mechanical characterization revealed that during deformation, there is an initial decrease in the hardness and tensile strength for the Al/CNTs and Al matrix. The initial decrease was attributed to the Bauschinger effect being more significant for the nanocomposites. The difference in the mechanical properties of the nanocomposites and Al matrix was attributed to distinct texture evolution during cold rolling.

Regulating surfactant strategy to synthesize Co@NCNT nanocomposites with conductive networks towards excellent electromagnetic wave absorption

In this paper, Prussian blue analogues (PBAs) with different morphologies have been synthesized in a co-precipitation process with Na3C6H5O7·2H2O and polyvinyl pyrrolidone (PVP) as surfactant, and then the electromagnetic wave absorption (EMWA) properties of their derivatives obtained via a pyrolysis reaction were investigated. To explore the best suitable pyrolysis temperature, PBA precursor synthesized via the addition of Na3C6H5O7·2H2O was annealed at four different temperatures (550/650/750/850 °C) to obtain the cobalt encapsulated in nitrogen-doped carbon nanotube (Co@NCNT) nanocomposites. Our results show that when the pyrolysis temperature is 650 °C, the Co@NCNT shows a minimum reflection loss (RLmin) of - 43.95 dB at the thickness of 2.05 mm, and the effective absorption bandwidth reaches 5.695 GHz, spanning the X and Ku bands. The excellent EMWA property is ascribed to the synergistic effect of dielectric and magnetic loss.

Silver Nanoparticle/Carbon Nanotube Hybrid Nanocomposites: One-Step Green Synthesis, Properties, and Applications.

Hybrid nanocomposites of silver nanoparticles and multiwalled carbon nanotubes (AgNPs/MWCNTs) were successfully synthesized by a green one-step method without using any organic solvent. The synthesis and attachment of AgNPs onto the surface of MWCNTs were performed simultaneously by chemical reduction. In addition to their synthesis, the sintering of AgNPs/MWCNTs can be carried out at room temperature. The proposed fabrication process is rapid, cost efficient, and ecofriendly compared with multistep conventional approaches. The prepared AgNPs/MWCNTs were characterized using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The transmittance and electrical properties of the transparent conductive films (TCF_Ag/CNT) fabricated using the prepared AgNPs/MWCNTs were characterized. The results showed that the TCF_Ag/CNT film has excellent properties, such as high flexible strength, good high transparency, and high conductivity, and could therefore be an effective substitute for conventional indium tin oxide (ITO) films with poor flexibility.

Retraction Note to: Synthesis of Carbon Nanotube and Zinc Oxide (CNT–ZnO) Nanocomposite

Retraction Note to: Synthesis of Carbon Nanotube and Zinc Oxide (CNT–ZnO) Nanocomposite

Unusual nonlinear switching in branched carbon nanotube nanocomposites

In this experimental study, we investigate the nonlinear dynamic response of nanocomposite beams composed of polybutylene terephthalate (PBT) and branched carbon nanotubes (bCNTs). By varying the weight fraction of bCNTs, we obtain frequency response curves for cantilever specimens under harmonic base excitations, measuring the tip displacement via 3D scanning laser vibrometry. Our findings reveal a surprising nonlinear softening trend in the steady-state response of the cantilevers, which gets switched into hardening for higher bCNT weight fractions and increasing oscillation amplitudes. The interaction of bCNTs with the thermoplastic hosting matrix results in stick-slip hysteresis, causing a softening nonlinearity that counteracts the geometric hardening associated with the nonlinear curvature of the first mode of the cantilever. However, when the weight fraction of bCNTs is greater than 1%, the bridging of the branched CNTs leads to the formation of a strong network that contributes to the hardening response at higher oscillation amplitudes. This mechanical behavior is detected by the trend of the nonlinear harmonic spectra and the equivalent damping ratio estimated using the half-power bandwidth method. To predict the observed unusual experimental behavior, we use a nonlinear mathematical model of the nanocomposite cantilever samples derived from a 3D mesoscale hysteretic model of the PBT/bCNT material. Our results suggest that the presence of bCNTs in a thermoplastic matrix is the main driver of the highly tunable nonlinear stiffness and damping capacity of the material. The reported experimental and modeling results provide valuable insights into the nonlinear dynamic behavior of PBT/bCNT nanocomposites and have potential applications in the design of advanced materials with tailored mechanical properties.

Optimization of PDMS -MWCNT nanocomposites for strong Ku-band absorption by integrating microwave simulations and genetic algorithm

This study combines genetic algorithm (GA) and microwave simulations to optimize the thickness of polymer nanocomposite layers for microwave absorption. The solution processed polydimethylsiloxane (PDMS)-multi wall carbon nanotube (MWCNT) nanocomposites are studied in the Ku-band (12.4–18 GHz). The most promising reflection loss (RL) characteristics (minimum RL value or RLmin, and RL ≤ -10 dB bandwidth) were found for bi-layered PDMS-MWCNT nanocomposites with MWCNT composition of 3 vol% and 1.5 vol% at an optimal thicknesses of 1 mm and 1 mm (overall thickness 2 mm), respectively. The simulated data match well with experimental data viz., the recorded RLmin value was −28.5 dB with an excellent RL ≤ −10 dB bandwidth of 4.5 GHz, indicating suitability for real time Ku-band applications. On the other hand, an appreciable RL value of −44.5 dB was found for single layer (3 vol% MWCNT) with a 2.5 GHz absorption bandwidth at a thickness of 6.4 mm. The error analysis of the simulated and experimental data was also carried out and it was found to be in the acceptable region (≤3 dB).

Effect of fabrication method on the physical properties of carbon-nanotube/silicone-rubber nanocomposite in high-voltage insulators

Effects of fog condensation and fine dust on the high-voltage insulator surface are harmful. The insulator housing material (silicone rubber) must be changed in order to allow a controlled leakage current to flow on the surface and causes Joule heating effect. Accordingly, surface temperature of the insulator is increased and fog condensation on the insulator surface is prevented. For this purpose, silicone rubber - multiwalled carbon nanotubes (MWCNT) nanocomposites (SRCNT) were prepared using two different processes: a solution-blending (SB) method and a dry-state of melt-blending (MB) method. Field Emission Scanning Electron Microscopy (FESEM) images indicated that the MWCNT dispersion in silicone rubber matrix of SRCNT samples produced by SB method is much better than that of MB method. Fourier Transform Infrared (FTIR) spectroscopy determined the possibility of a greater reduction in hydrophobicity properties in the sample prepared by the SB method compared to the sample made by the MB method, and the contact angle measurements confirmed this expectation. Furthermore, in a same MWCNT concentration, the electrical conductivity of SRCNT samples prepared by SB method are greater than those produced by MB method. Results showed that MB is a high efficient method for producing the SRCNT in a large amount.

Carbon nanotube (CNT) reinforced cementitious composites using carboxymethyl cellulose (CMC) treatment for enhanced dispersion, mechanical, and piezoresistive properties

Controlling CNT dispersion has been the key challenge for CNT nanocomposites. This study investigated the dispersion, mechanical and piezoresistive properties of CNT reinforced cementitious composites using carboxymethyl cellulose (CMC) treatment by comparing with three other existing mixing methods, including direct mixing, surface treatments using octenyl succinic anhydride (OSA) modified tapioca starch as a polymeric additive, and sodium dodecylbenzene sulfonate (NaDDBS) as a surfactant. The experimental results first indicated that the CMC treatment was categorized as a noncovalent functionalization and showed effectiveness in improving CNT dispersion, compressive strength, modulus of elasticity, Poisson ratio, and piezoresistive sensitivity of CNT reinforced cementitious composites.