Multi-walled Carbon Nanotubes Nanocomposites Research Articles

Constructing nanopores in poly(oxymethylene)/multi-wall carbon nanotube nanocomposites via poly(l-lactide) assisting for improving electromagnetic interference shielding

Lightweight and high-performance conductive polymer composites (CPCs) have attracted much attention for electromagnetic interference (EMI) shielding. Herein, the porous structure was constructed in poly(oxymethylene)/multi-wall carbon nanotube (POM/MWCNT) nanocomposites via assisting by poly(l-lactide) (PLLA). First, the POM/PLLA/MWCNT (S-PMLNT) nanocomposites were obtained by melt mixing and compression molding. Second, the nanoporous POM/MWCNT (P-PMNT) nanocomposites were fabricated by selectively dissolving PLLA, solvent exchanging and freeze-drying. Because of well miscible between PLLA and POM, the homogeneous nanopores could be successfully fabricated in the P-PMNT composites by removing the PLLA phase. The multiple reflections and scattering of microwaves happened on the walls of these nanopores, which endowed the P-PMNT nanocomposites having higher EMI shielding effectiveness (SE) in comparison of the S-PMLNT nanocomposites, although the P-PMNT nanocomposites exhibited the lower electrical conductivity. For example, the S-PMLNT samples with 10 wt% MWCNTs showed an EMI SE of 48.1 dB and an electrical conductivity of 333 S/m, which changed to 58.6 dB in EMI SE and 125 S/m in electrical conductivity after removing PLLA phase. Furthermore, the P-PMNT10 nanocomposites had outstanding the EMI normal SE (SE/d) of 29.3 dB mm−1 and the EMI specific shielding effectiveness (SSE/d) of 344.4 dB cm2 g−1 because of their low density. In addition, the P-PMNT nanocomposites maintained high compression and tensile strength simultaneously.

Tangled silver nanoparticles embedded polythiophene-functionalized multiwalled carbon nanotube nanocomposites with remarkable electrical and thermal properties

Tangled silver nanoparticles embedded layered polythiophene-functionalized multiwalled carbon nanotube ternary nanocomposite (PTCNT-COOH 300 Ag) has been prepared by ascorbic acid reduction of silver nitrate solution in presence of aqueous dispersion of polythiophene-functionalized multiwalled carbon nanotube (PTCNT-COOH) binary nanocomposites. Binary polythiophene–functionalized multiwalled carbon nanotube nanocomposites have been prepared by in-situ chemical oxidative polymerization of thiophene monomer stabilized by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micelles in presence of functionalized multiwalled carbon nanotubes (MWCNT-COOH) using ferric chloride (FeCl3) as an oxidizing agent in chloroform solvent. The structural formation and composition of binary and ternary nanocomposites have been confirmed by fourier transform infrared spectroscopy, fourier transform Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and wide angle X-ray diffraction studies. Scanning electron microscopy (SEM) studies have revealed the nanofibrous morphology in binary nanocomposites (PTCNT-COOHs), whereas in ternary nanocomposite (PTCNT-COOH 300 Ag), silver nanoparticles were densely embedded as nanoparticles over nanofibrous structure. Transmission electron microscopic (TEM) images have provided the evidence regarding silver nanoparticles that existed in a tangled state over the nanofibrous structure. Stable dispersion of binary nanocomposites (PTCNT-COOHs) in water, ethanol and chloroform enabled us to record the UV–visible absorption spectra which have shown two peaks at 260 nm and 360 nm corresponding to π-π* transition from aromatic rings and π-polaron absorption of polythiophene respectively. On the other hand, ternary nanocomposite have shown surface plasmon resonance as broad peak tailing to 550 nm. The electrical conductivity of nanocomposites PTCNT-COOH 100 (binary nanocomposite), PTCNT-COOH 200 (binary nanocomposite), PTCNT-COOH 300 (binary nanocomposite), pristine MWCNT, functionalized MWCNT-COOH, MWCNT-COOH Ag (binary nanocomposite) and PTCNT-COOH 300 Ag (ternary nanocomposite) were 4.42 × 10−2, 5.30 × 10−1, 1.64, 8.66, 2.80, 12.40 and 80.76 S/cm respectively. The enhanced electrical conductivity of ternary nanocomposite was due to the effective charge transport through polythiophene layer which act as conductive bridge between multiwalled carbon nanotube and silver nanoparticles. Thermogravimetric analysis have revealed that high thermal stability of ternary silver nanocomposite of PTCNT-COOH 300 Ag up to 620 °C for 10% weight loss. Silver nanoparticles embedded ternary nanocomposite in basic medium shows least leaching effect, therefore it could be potentially useful in catalytical applications.

A sensitive nanocomposite design via carbon nanotube and silver nanoparticles: Selective probing of Emedastine Difumarate

In this study, a novel and sensitive nanocomposite of carboxylate-functionalized multiwalled carbon nanotube (COOH-fMWCNT) and silver nanoparticles (AgNPs) was fabricated and used to modify a glassy carbon electrode (GCE) by a simple drop casting method. Modified electrode was then applied for selective determination of emedastine difumarate (EDD). The COOH-fMWCNT/AgNPs nanocomposite was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV). EDD showed two oxidation peaks at 0.634 and 1.2 V on the GCE surface. CV results of COOH-fMWCNT/AgNPs/GCE displayed superior electrocatalytic performance in terms of anodic peak current of EDD when compared to AgNPs/GCE, MWCNT/GCE, and COOH-fMWCNT/GCE. The experimental conditions such as effect of pH, supporting electrolyte, effect of accumulation time and potential, scan rate were optimized for getting intense current signals of the target analyte. Under optimized conditions, COOH-fMWCNT/AgNPs/GCE showed a linear current response for oxidation of EDD in the range of 1.0 × 10−7–1.0 × 10-4 M, with a limit of detection (LOD) and quantification (LOQ) of 5.25 nM, 15.9 nM, respectively, in 0.1 M phosphate buffer solution at pH 2.0 using differential pulse adsorptive stripping voltammetry technique. The proposed method was successfully applied for determination of EDD in pharmaceutical dosage form. Satisfactory recovery percentages were achieved from eye drop sample with acceptable RSD values (less than 2 %). Furthermore, the reproducibility, stability and repeatability of the modified electrode were studied.

Positive effects of concomitant heavy metals and their reduzates on hexavalent chromium removal in microbial fuel cells.

Cr(vi) laden wastewaters generally comprise a range of multiple heavy metals such as Au(iii) and Cu(ii) with great toxicity. In the present study, cooperative cathode modification by biogenic Au nanoparticles (BioAu) reduced from aqueous Au(iii) and in situ Cu(ii) co-reduction were investigated for the first time to enhance Cr(vi) removal in microbial fuel cells (MFCs). With the co-existence of Cu(ii) in the catholyte, the MFC with carbon cloth modified with nanocomposites of multi-walled carbon nanotubes blended with BioAu (BioAu/MWCNT) obtained the highest Cr(vi) removal rate (4.07 ± 0.01 mg L−1 h−1) and power density (309.34 ± 17.65 mW m−2), which were 2.73 and 3.30 times as high as those for the control, respectively. The enhancements were caused by BioAu/MWCNT composites and deposited reduzates of Cu(ii) on the cathode surface, which increased the adsorption capacity, electronic conductivity and electrocatalytic activity of the cathode. This study provides an alternative approach for efficiently remediating co-contamination of multiple heavy metals and simultaneous bioenergy recovery.

Studies on the Improvement of Mechanical and Thermal Properties of Nylon 66 by Using Multi-Walled Carbon Nanotubes Nano composites

Studies on the Improvement of Mechanical and Thermal Properties of Nylon 66 by Using Multi-Walled Carbon Nanotubes Nano composites

A non-enzymatic electrochemical approach for l-lactic acid sensor development based on CuO·MWCNT nanocomposites modified with a Nafion matrix

Copper oxide decorated multi-walled carbon nanotube nanocomposites (CuO·MWCNT NCs) were prepared using a simple wet-chemical technique in basic medium.

Interfacially Interactive Ternary Silver-Supported Polyaniline/Multiwalled Carbon Nanotube Nanocomposites for Catalytic and Antibacterial Activity.

Herein, a protocol strategy has been designed for the preparation of ternary silver nanoparticles-supported polyaniline multiwalled carbon nanotube (Ag NPs–PANI/MWCNT) nanocomposites with a chemical interaction for catalytic and antibacterial activity. The morphological study confirmed that Ag NPs were immobilized on the surface of PANI, and afterward, Ag NPs–PANI were mixed with the MWCNTs. The X-ray diffraction technique revealed the face-centered cubic structure of Ag NPs, and the X-ray photoelectron spectroscopy study revealed the chemical constituent and signature of π–π* and C–N interactions in the nanocomposites. The ternary Ag NPs–PANI/MWCNTs nanocomposites have the apparent rate of reaction (Kapp) as 5.4 × 10–3 s–1, higher than binary nanocomposites for catalytic reduction of 4-nitrophenol to 4-aminophenol at room temperature. Antibacterial activity of Ag NPs–PANI/MWCNT nanocomposites is higher against pathogenic bacteria. Thereafter, because of multifold applications of ternary nanocomposites, they have a broad scope in the field of environmental and healthcare sectors.

A sensitive and selective electrochemical determination of Diazinon based on Au–Pd/rGO–MWCNTs composite: analytical application in water, fruit and vegetable samples

In this research, a sensitive and selective electrochemical sensor based on bimetallic gold (Au) and palladium (Pd) nanoparticles coated on mixture of reduced graphene oxide (rGO) and multiwall carbon nanotube (MWCNTs) nanocomposite was constructed by using glassy carbon electrode which has been developed for determination of an organophosphorus (OPs) insecticide, Diazinon. Au–Pd/rGO–MWCNTs was synthesized by chemical reduction method, and the final product was investigated by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. Under optimized conditions, the proposed sensor showed that the stripping oxidation peak current of Diazinon was linearly proportional to its concentrations in an appropriate range of 0.009 to 11.3 µM with a limit of detection and limit of quantification of 0.002 and 0.009 µM, respectively. The selectivity and reproducibility of the proposed sensor were checked, and the results showed that these factors of the sensor were in high level. Finally, the Au–Pd/rGO–MWCNTs/GCE was successfully used for measurement of target analyte in water, apple and cucumber samples recoveries ranging from 96 to 105%.

A facile rheological approach for the evaluation of “super toughness point” of compatibilized HDPE / MWCNT nanocomposites

Fast and efficient determination of the optimal mechanical property of a polymer/CNT nanocomposite is crucial to develop polymer conductive nanocomposites. This work establishes a rheological approach to evaluate the super-toughness point of compatibilized high density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) nanocomposites. Results illustrate that three types of HDPE/MWCNT nanocomposites exhibit obvious gel plateaus in the dynamic rheological curves and the gel points of nanocomposites with compatibilizer shift to the low MWCNTs loading. The super-toughness points of HDPE/MWCNT nanocomposites with compatibilizers show the correspondence with the gel points acquired from the rheological data, indicating that dynamic rheology is an effective way to determine the super-toughness points of HDPE/MWCNT nanocomposites with compatibilizers. Furthermore, unique network structure at the gel points is directly observed and the new mechanism of toughness is proposed. This study provides new insights for effective control of the structures and properties of polymer/CNT nanocomposites.

Hybrid Nanocomposites of Multi-walled Carbon Nanotubes (MWCNTs) and CuO as Electrode Materials for Energy Storage Devices

The search for electrode materials as a potential candidate for Li-ion based batteries is important to achieve high-performance devices. This work constitutes the experimental and theoretical investigation of structural stability and electrochemical behavior of cupric oxide and multi-walled carbon nanotubes (CuO/MWNNTs) nanocomposites. The electrochemical performance of nanocomposites was gauged employing charge/discharge and cyclic voltammetry studies. It is shown that electrochemical properties of pure materials, due to the synergistic effect, are considerably enhanced in CuO/MWNNTs composites. As a result, high rate capability and better cycling stability is observed in CuO-5%MWCNTs samples. In addition, this composite possesses better specific capacity 810 mAh g−1 and a high columbic efficiency of 80.86%. The DFT calculations also confirmed the improved electrochemical properties of MWCNTs in the presence of CuO nanoparticles.

Solution blow spun graded dielectrics based on poly(vinylidene fluoride)/multi-walled carbon nanotubes nanocomposites

For the first time polymer-based graded nanocomposites were prepared by solution blow spinning, SBS, looking for new materials with optimal dielectric behavior. SBS was used as the processing method to apply layer by layer multi-walled carbon nanotubes, MWCNT, filled poly(vinylidene fluoride), PVDF, nanocomposites of well controlled compositions. Different configurations in terms of the disposition of layers with distinct concentration of MWCNT were considered. The structure, morphology and thermal behavior of the materials prepared were investigated so as their broadband dielectric properties in order to find and understand possible correlations. Morphological and slight structural changes were observed as a function of MWCNT concentration; however, they do not seem to be the main factors affecting the variations observed in the dielectric behavior of the materials under study. It was demonstrated that a particular design of PVDF based dielectrics, for which there is a particular gradient of MWCNT concentration, importantly increases the permittivity without increasing dielectric losses.

CuO Nanoparticles/Multi-Walled Carbon Nanotubes (MWCNTs) Nanocomposites for Flexible Supercapacitors.

Copper oxide nanoparticles (CuO NPs)/multi-walled carbon nanotube (MWCNTs) nanocomposites were synthesized by a simple in-situ co-precipitation technique. MWCNTs networks acted as an ideal supporter for active material and permitted formation of free standing hybrid nanocomposite in the sheet form. Structural properties of CuONPs/MWCNTs nanocomposites were examined using X-ray diffraction (XRD), X-ray photon spectroscopy (XPS) and Transmission electron microscopy (TEM). By using three-electrode system, the electrochemical performance of the CuONPs/MWCNTs nanocomposite was investigated. The heat treated sample CuONPs/MWCNTs(H) yielded specific capacitance of 452.8 Fg-1 under 10 mV s-1 scan rate. Also, the nanocomposite exhibited good cyclic stability with 90% capacity retention over 500 charge-discharge cycles. This free-standing thin nanocomposite electrode can serve as a potential candidate as electrode for energy storage systems.

Online coupling of an electrochemically fabricated solid-phase microextraction probe and a miniature mass spectrometer for enrichment and analysis of chemical contaminants in infant drinks

A streamlined analytical workflow was developed for the analysis of infant drink samples using a miniature mass spectrometry system preceded by solid-phase microextraction (SPME) and extraction nano-electrospray ionization. Potential chemical contaminants in infant drinks (milk, lactic acid bacteria beverage, and fruit juice) were extracted and enriched using a custom-made stainless-steel SPME probe, which was coated with a thin layer of polyaniline and multi-walled carbon nanotubes nanocomposites (PANI/MWCNTs) by electrochemical deposition. The resulting porous microstructure has a larger surface area and enhanced microextraction efficiency, with enrichment factors ranging from 3055 to 8695 for exemplary analytes of antibiotics, bisphenol A, and perfluorinated compounds. The enriched analytes on the electrochemically fabricated SPME probe were simultaneously desorbed and ionized within a pulled glass capillary by extraction nano-electrospray ionization. The ionized species were subjected to instrumental analysis on a miniature ion trap mass spectrometer with adequate tandem mass spectrometry capability. The developed method was optimized and validated in terms of sensitivity, linearity, repeatability, and recovery. The integrated experimental protocol combining SPME, ambient ionization, and miniature mass spectrometry is promising for rapid, on-site screening of hazardous substances in food to ensure consumer health.

Role of graphene additive on wear and electrochemical corrosion behaviour of plasma electrolytic oxidation (PEO) coatings on Mg–MWCNT nanocomposite

ABSTRACT In this study, wear and electrochemical corrosion behaviour of as-cast magnesium (Mg)/multiwall carbon nanotube (MWCNT) and plasma electrolytic oxidation (PEO) coated Mg/MWCNT samples were evaluated by dry sliding wear tests and potentiodynamic corrosion tests, respectively. In this respect, Mg/MWCNT composite was manufactured by stir casting route. X-ray diffraction (XRD) analysis shows that the presence of Mg, MgO and Mg2SiO4 phases for coated samples. The corrosion rate of the coated samples is about 1.6 times lower than that of un-coated Mg–MWCNT composite. From the wear tests, it is concluded that PEO coating leads to significant improvement in wear resistance in comparison with un-coated Mg/MWCNT composite. It is observed that wear mechanisms are abrasion and oxidation.

The composite of carbon nanotubes and cobalt(II)-intercalated montmorillonite for enhanced electrocatalytic oxygen reduction

Due to the rapid development of fuel cells, the fabrication of electrocatalysts for oxygen reduction (ORR) with high performance and low-cost is of great significance. Herein, cobalt cations-intercalated montmorillonite (Co-MMT) was prepared by a simple cation-exchange reaction between Na-MMT and cobalt cations. A detailed ORR investigation indicates that the as-prepared nanocomposite of Co-MMT and multiwalled carbon nanotubes (Co-MMT/MWCNT) exhibits better ORR catalytic activity in aqueous alkaline medium with a 4e-route mechanism than Na-MMT, Co-MMT and MWCNT, suggesting the synergistic effect between Co-MMT and MWCNT. Moreover, further research shows that Co-MMT/MWCNT hybrid demonstrated more positive onset potential for ORR, higher oxygen reduction peak current than commercial 5% Pt/C ORR electrocatalyst.

Determination of an organophosphate pesticide using antibody immobilised hybrid nanocomposites

ABSTRACT In this study, the malathion specific polyclonal antibodies (Abs) were raised for the fabrication of an electrochemical immunosensor using poly (3,4-ethylenedioxythiophene) (PEDOT) and carboxylated multiwalled carbon nanotubes (c-MWCNTs) nanocomposites. The conjugation of hapten (malathion diacid) with bovine serum albumin (BSA) through N-hydroxysuccinimide (NHS) ester method was optimised for the generation of Abs. New Zealand White (NZW) male rabbits were immunised subcutaneously for the development of Abs followed by characterisation and purification. The purified Abs were covalently immobilised on nanocomposites deposited onto fluorine tin oxide (FTO). Based on immunoreaction between malathion and anti-malathion Abs, the DPV peak current was found to be inversely proportional to increase in malathion concentration. The detection limit was 1.1 fM under all the optimised experimental parameters. The immunosensor was found to be specific as low current response was observed for malathion only in comparison to other interferents. Malathion recoveries from the spiked sample were found to be superior via immunosensor than HPLC.

Dry sliding wear behaviour of multi walled carbon nanotubes reinforced aluminium composites produced by powder metallurgy technique

The nanocomposites of Multi-Walled Carbon Nano Tubes (MWCNTs) having weight fractions of 0, 0.25, 0.5, 0.75 and 1.0 wt%, reinforced in 200 mesh size Aluminium (Al) particles, produced through Powder Metallurgy (PM) process. Uniform distribution of MWCNTs was achieved using ultrasonic blending and mechanical planetary ball milling. Dry sliding wear behavior of fabricated composites were studied in accordance with the ASTM G99-95a standard. Wear behavior were studied for various sliding distance, load, and disc rotation speeds. The results showed that, wear rate increased with increasing sliding distance and load because of an increased of temperature during an investigation. However, the wear rate decreased with an increased speed due to the formation of a stable tribolayer. Further Al 0.5 wt% of MWCNT nanocomposites were found to have better wear resistance characteristics compared to others. The resistance to wear enhanced because of bonding among matrix and MWCNTs and the formation of tribo layer was characterized using Scanning Electron Microscopy.

Light-induced reversible phase transition in polyvinylidene fluoride-based nanocomposites

We report switching behavior between the ferroelectric β phase and the paraelectric α phase in polyvinylidene fluoride–multiwalled carbon nanotube (PVDF–CNT) nanocomposite. The PVDF–CNT nanocomposite thin films are prepared on Au/Si substrates using spin coating technique. Various characterization techniques reveal the interaction of PVDF with CNTs as a nucleating agent for nucleating ferroelectric β phase in PVDF. A wavelength-independent reversible phase transformation behavior is observed for the PVDF–CNT nanocomposite during the measurement of laser power modulated micro-Raman spectroscopy (533 and 632 nm lasers). This observation opens up an innovative route where we can control the interactions between polar nanocarbons and PVDF using visible light.

Morphologically correlated surface characteristics of poly (trimethylene terephthalate)/multiwalled carbon nanotube nanocomposites

In the present work the formation of nano-composites by blending an insulator polymer, poly (trimethylene terephthalate), PTT, with a conducting nano-filler (multiwalled carbon nanotubes, MWCNT) is studied and their surface properties, especially wettability and morphology, are investigated. The PTT/MWCNT nanocomposites show significant enhancements in their non-wettability with the highest water contact angle (θ) of 115° for the PTT/0.5%MWCNT composite, compared to 74° for PTT. Since MWCNT is hydrophobic in nature no correlation of MWCNT content with θ value is seen but a direct correlation of θ with surface roughness data obtained from scanning electron microscopy and atomic force microscopy studies could be made. Various wettability parameters including total surface free energy, work of adhesion, interfacial free energy, spreading coefficient and Girifalco–Good’s interaction parameter were also evaluated for the nanocomposites.Highlights• Effect of conducting filler MWCNT on the surface properties of an insulating polymer PTT was investigated by developing a series of their nano-composites.• Water contact angle θ, wetting parameters like γs, WA, Sc, ϕ could be evaluated and surface roughness of the composites could be found out by SEM and AFM.• Attempt was made to correlate the non-wetting properties of PTT/MWCNT nanocomposites with the MWCNT content and also with the surface morphology/roughness of the composites.• A significant enhancement in hydrophobicity is seen by incorporating just 0.5% MWCNT in PTT with θ value going up to 115° compared to 74° for neat PTT.

Tuning of electronic and electrical behaviour of MWCNTs-TiO2 nanocomposites

The improvement of electronic structure and electrical behaviour of low-density materials have been of great concern. Multiwall carbon nanotube (MWCNT) has been identified as a low-density material, which needs attention to be used mostly as a strengthening phase in lightweight metal lattice composites (MLC). In this work, vaporization and drying process were used to produce TiO2 incorporated MWCNTs nanocomposites. The incorporation of TiO2 is to improve electronic system as well as electrical behaviour of MWCNTs in oxidized atmosphere, which is essential in most of MLC processing methods. We have used field-emission scanning electron microscopy Raman spectroscopy, X-ray diffraction and X-ray photoemission spectroscopy techniques for the study of structural and electronic properties; whereas current-voltage technique was used for the study of electrical behaviour of the nanocomposites. The observed change in electrical behaviour of the nanocomposites with improvement of electric/bonding structure indicates possibilities of the material properties be tailored for electronic/electrical devices as well as photo-catalytic activity applications.