Multi-walled Carbon Nanotubes Nanocomposites Research Articles

An Electrochemical Immunosensor with PEDOT: PSS/MWCNTs-COOH Nanocomposites as a Modified Working Electrode Material for Detecting Tau-441

The progression of Alzheimer’s disease (AD) is positively correlated with the phosphorylation damage of Tau-441 protein, which is the marker with the most potential for the early detection of AD. The low content of Tau-441 in human serum is a major difficulty for the realization of content detection. Herein, we prepared an electrochemical immunosensor modified with Poly(3,4-ethylene-dioxythiophene)-poly (styrene sulfonate) (PEDOT: PSS)/Carboxylated multi-walled carbon nanotube (MWCNTs-COOH) nanocomposites based on electrochemical immunoassay technology for the low-concentration detection of Tau-441. The immunosensor based on the nanocomposite can take advantage of the characteristics of conductive polymers to achieve electrical signal amplification and use MWCNTs-COOH to increase the contact area of the active site and bond with the Tau-441 antibodies on the electrode. The physicochemical and electrical properties of PEDOT: PSS/MWCNTs-COOH were studied by in situ characterization techniques and electrochemical characterization methods, indicating that the immunosensor has high selectivity and sensitivity to the Tau-441 immune reaction. Under optimized optimal conditions, the electrochemical immunosensor detected a range of concentrations of Tau-441 to obtain a low detection of limit (0.0074 ng mL−1) and demonstrated good detection performance through actual human serum sample testing experiments. Therefore, the study provides an effective reference value for the early diagnosis of AD.

Tailoring Optoelectronic Properties of ZnO Nanoparticles via Incorporation of Multiwalled Carbon Nanotube Contents on of ZnO/MWCNT Nanocomposites

The present study demonstrates the tailoring of optoelectronic properties of ZnO nanoparticles (NPs) by adding multi-walled carbon nanotubes (MWCNTs) at different weight ratios. ZnO/MWCNT nanocomposites were successfully prepared using the solution blending method, and the optical spectra of all samples were determined using a UV–vis spectrometer. An increase in the optical absorption coefficient (α) and extinction coefficient (k) was observed with an increase in MWCNT content, resulting in the significant ability to attenuate incident light in ZnO/MWCNT nanocomposites compared to pure ZnO NPs. The optical band gap of pure ZnO NPs decreased from 3.26 eV to 2.58 eV in the ZnO/50 wt% MWCNT nanocomposite. The refractive index values ranged from 1.66 to 1.61 as the wavelength varied between 400 nm and 700 nm. Furthermore, the incorporation of MWCNTs in the ZnO/MWCNT nanocomposite had an impact on various dispersion parameters related to the refractive index. With increasing MWCNT content, the dielectric constant (ε 0) decreased from 2.40 to 1.96, while the mean oscillator wavelength (λ 0) increased from 157.7 nm to 164.2 nm and the oscillator strength (S0) decreased from 5.93 × 10−5 nm−2 to 3.70 × 10−6 nm−2. The localized density of state (N/m*) increased from 7.45 × 1057 to 20.8 × 1057 (m3 Kg) −1, and the long wavelength refractive index (ε ∞) rose from 3.683 to 4.745. Moreover, the plasma frequency (ω p) of the electron exhibited an increase from 2.15 × 1031 to 6.01 × 1031 Hz. These findings highlight the potential of tailoring the optoelectronic properties of ZnO NPs through the incorporation of MWCNTs, paving the way for the development of novel materials with improved optoelectronic characteristics for a wide range of applications.

PVDF/poly(3-methylthiophene)/MWCNT nanocomposites for EMI shielding in the microwave range

This work presents a new approach to enhance EMI shielding efficiency of nanocomposites of dielectric polymers, multiwalled carbon nanotubes (MWCNTs) and intrinsically conducting polymers for account of using core-shell morphology for conducting components. To realize this approach new ternary nanocomposites of poly(vinylidene fluoride) (PVDF), MWCNTs and poly(3-methylthiophene) doped by Cl− anions (P3MT) were prepared through synthesis of thermally stable core/shell nanocomposites PVDF/P3MT and MWCNT/P3MT. These binary nanocomposites were mixed with pure MWCNTs or PVDF followed by compression molding to prepare the ternary nanocomposites of different morphology to discriminate their EMI shielding properties in a wide frequency range (1–67 GHz). Values of the tangent of dielectric loss angle, the efficiency of transmission, reflection and absorption of microwave radiation, and shielding efficiency (SE) of the specified materials were found from analysis of spectral dependences of their complex dielectric constants. It was shown that while the melt mixing of the binary PVDF/P3MT nanocomposite with MWCNTs both in a pure state and in the binary nanocomposite (MWCNT/P3MT) expectedly strongly enhances SE of the former, this effect is non-linear and depends on presence/absence of the P3MT shell on the MWCNT core. The ternary nanocomposite PVDF/P3MT/MWCNT made of the binary polymer-polymer nanocomposite PVDF/P3MT and pure MWCNTs showed highest SE values at the frequencies above 4.5 GHz up to 68.4 dB at 67 GHz in the case of the 1 mm thickness sample. However, below 4.5 GHz the SE was higher in the case of the ternary nanocomposites containing core/shell MWCNT/P3MT nanocomposite instead of pure MWCNT.

One-Pot Synthesis of Semiconducting Quantum Dots–Organic Linker–Carbon Nanotubes for Potential Applications in Bulk Heterojunction Solar Cells

Materials and composites with the ability to convert light into electricity are essential for a variety of applications, including solar cells. The development of materials and processes needed to boost the conversion efficiency of solar cell materials will play a key role in providing pathways for dependable light to electric energy conversion. Here, we show a simple, single-step technique to synthesize photoactive nanocomposites by coupling carbon nanotubes with semiconducting quantum dots using a molecular linker. We also discuss and demonstrate the potential application of nanocomposite for the fabrication of bulk heterojunction solar cells. Cadmium selenide (CdSe) quantum dots (QDs) were attached to multiwall carbon nanotubes (MWCNTs) using perylene-3, 4, 9, 10-tetracarboxylic-3, 4, 9, 10-dianhydride (PTCDA) as a molecular linker through a one-step synthetic route. Our investigations revealed that PTCDA tremendously boosts the density of QDs on MWCNT surfaces and leads to several interesting optical and electrical properties. Furthermore, the QD–PTCDA–MWCNTs nanocomposites displayed a semiconducting behavior, in sharp contrast to the metallic behavior of the MWCNTs. These studies indicate that, PTCDA interfaced between QDs and MWCNTs, acted as a molecular bridge which may facilitate the charge transfer between QDs and MWCNTs. We believe that the investigations presented here are important to discover simple synthetic routes for obtaining photoactive nanocomposites with several potential applications in the field of opto-electronics as well as energy conversion devices.

Studies on sustainable CuO/ZnO@MWCNT electrodes and their supercapacitive performances in redox additive electrolyte

Supercapacitive performances of copper oxide and zinc oxide loaded multiwalled carbon nanotube (CuO/ZnO@MWCNT - CZM) nanocomposites (NCs) in redox additive electrolyte were reported. CZM NCs were hydrothermally synthesized and calcinated at 500 °C for 5 h. The structural characteristics of the prepared NCs were examined using powder X-ray diffraction analysis. Scanning electron microscopy and vibrational spectroscopy techniques were employed to analyse the surface features and molecular interactions of the prepared NCs, respectively. The working electrodes were fabricated using CZM NCs and tested in pure 3 M potassium hydroxide (KOH) and 0.2 M potassium ferrocyanide added 3 M KOH electrolytes (K4[Fe(CN)6] – RAE). Fabricated electrode exhibited the specific capacitances of 199.4 Fg−1 (at 8 Ag−1) in KOH and 1829.43 Fg−1 (at 15 Ag−1) in RAE, respectively. Furthermore, an asymmetrical-type supercapacitor was constructed using CZM NCs and activated carbon-coated Ni foil as the working and counter electrodes, respectively. Fabricated device demonstrated 18.5 W h kg−1 and 1875 W kg−1 of energy and power densities, respectively, with 83.05 Fg−1 of specific capacitance in RAE. Electrochemical studies confirmed that the prepared CZM NCs demonstrated superior performances in RAE.

Preparation and Characterization Techniques of High-Density Polyethylene (HDPE) Reinforced with Multi-walled Carbon Nanotube (MWCNT) Nano-composites—A Review

Preparation and Characterization Techniques of High-Density Polyethylene (HDPE) Reinforced with Multi-walled Carbon Nanotube (MWCNT) Nano-composites—A Review

Determination of electromagnetic traveling path in polymer/multi‐walled carbon nanotube nanocomposite foams and analysis by Taguchi technique

AbstractThe attenuation of electromagnetic (EM) energy with polymeric nanocomposite foams is significant because the microwave energy is diminished by multiscattering of EM into microcellular structure. In this study, acrylonitrile butadiene styrene (ABS) and multi‐walled carbon nanotubes (MWCNTs) nanocomposite foams were fabricated via a chemical foaming in an injection‐molding process. It was demonstrated that the skin depth in foamed ABS/MWCNT specimens was fallen dramatically compared to their solid counterparts. The diminution of skin depth for foamed ABS/1 wt% of MWCNT nanocomposite was 21.7% compared to solid pure ABS. The reflectance of pure ABS was decreased by foaming but it was increased in foamed ABS/MWCNT nanocomposite. The absorption of microwave was improved by foaming and adding MWCNTs in ABS matrix. The utmost value of the experimental absorption shielding effectiveness (SEA. experimental), 14.26 dB, was found for the foamed ABS/1 wt% of MWCNT, holding pressure of 2 s and cooling time of 60 s F8, at 8.7 GHz. It was demonstrated that traveling path of EM wave was prolonged by the introduction of microcellular structure in ABS/MWCNT nanocomposite. Moreover, the contribution of MWCNT, holding pressure time, and cooling time to traveling path were achieved 76.7%, 8.5%, and 7.3%, respectively.Highlights ABS/MWCNTs nanocomposite foams were fabricated by chemical foaming process. Skin depth in foamed nanocomposite samples was fallen compared to solids. Reflectance of pure ABS was decreased by foaming. Absorption of microwave was improved by foaming and MWCNTs. Traveling path of EM wave was prolonged by microcellular structure.

Thermal performance and corrosion resistance analysis of inorganic eutectic phase change material with one dimensional carbon nanomaterial

The inherent thermal characteristics, supercooling phenomenon, and corrosion issues associated with salt hydrate phase change materials (PCMs) limit their practical applications. In this research work, we report a newly formulated eutectic salt hydrate PCM using a) sodium sulphate decahydrate (SSD) & b) sodium phosphate dibasic dodecahydrate (SPDD); with a focus on customizing its properties to enhance its suitability for low temperature thermal regulation (achieving a melting point of 27.8 °C and a high heat storage capacity of 215 J/g). Additionally, we have successfully reduced the degree of supercooling and introduced corrosion resistant properties to this PCM. To enhance both the thermal energy transfer rate and optical absorbance of the eutectic PCM, we have incorporated one-dimensional (1D) multiwall carbon nanotube (MWCNT) at various weight fractions, extending up to 0.9 %, utilizing a two-step method. The dispersion and chemical stability of SSD/SPDD + MWCNT nanocomposite are verified through the morphological visual and spectral peaks obtained in Fourier transfer infrared spectroscopy. Additionally, studies evaluating the optical and thermal property reveal a substantial 500 % increase in absorbance, a notable 77.9 % reduction in transmissibility, a thermal conductivity increase from 0.464 W/m⋅K to 0.742 W/m⋅K (reflecting a 59.9 % increment), and the retention of a consistent melting enthalpy of 218.6 J/g. This stability is attributed to the intermolecular interaction with MWCNT. Similary, the degree of supercooling (ΔTs) for the SSD/SPDD EPCM containing MWCNT decreased to 2.2 °C from 16.5 °C, marking an 86 % reduction compared to the pure eutectic salt solution. Furthermore, this composite demonstrated enhanced thermal and chemical stability throughout 200 thermal cycles. Auxiliary ANSYS simulation, with transient boundary condition, are provided to analyze the heat transfer interactions between the thermic fluid and the newly developed PCM when integrated into a thermal regulation system. Subsequently, a corrosion analysis of the developed eutectic PCM and the nanocomposite eutectic PCM exhibits a corrosion rate of 0.018 mpy, well below the permissible level (<5mpy). The insights gained from the development of this nanocomposite PCM offer valuable guidance for the design and creation of tailored eutectic PCM for low-temperature thermal regulation systems, resulting in significant energy savings.

Electrical and optical properties of polyamide 6 nanocomposites with multi-walled carbon nanotubes

In this work, quantum chemical modeling, electrical conductivity, Raman scattering, and photoluminescence of polyamide 6 nanocomposites with multi-walled carbon nanotubes (0–2.5 vol%) were investigated. It was shown that the concentration dependence of the electrical conductivity obeys the percolation theory and has the value of percolation threshold 1.41 vol%. The conductivity value of the composite at 2.5 vol% nanotubes is 1.1*10-3 S/cm. It was found that in PA6 nanocomposites filled with MWCNT an increase in the concentration of nanotubes from 0.001 to 0.015 vol%, namely in the pre-percolation region of electrical conductivity, due to a significant restructuring of the Raman spectra, which consists in a shift of the vibrational modes of the methylene groups CH2 and amide I, as well as in a change of their relative intensities. From the photoluminescence spectra of PA6-MWCNT, it can be seen, that the carbon nanotubes largely determine the conformational changes in the polymer matrix and have little effect on the defective structure of the polymer itself.The goal: to establish the mechanisms of electrical conductivity and the interaction of nanotubes with polyamide macromolecules and its influence on the electronic and optical properties of nanocomposites of polyamide multi-walled carbon nanotubes.

Design ofan electrochemical aptasensor in the presence of an array of gold nanostructure and a GO-MWCNTs nanocomposite: application in diagnosis of Alzheimer's disease.

Alzheimer's disease (AD) is considered one of the main progressive chronic diseases in elderly individuals. Early diagnosis using related biomarkers, specifically beta-amyloid peptide (Aβ), allows finding expected treatment routes. Here, we developed an electrochemical aptasensing platform for AD by employing a glassy carbon electrode (GCE) modified with a layer of jagged gold (JG) nanostructure (diameter: 60-185nm) and graphene oxide-carboxylic acid functionalized multiwalled carbon nanotubes (GO-c-MWCNTs) nanocomposite. These surface modifications acted as the signal amplifier and provided an optimum nano-interface substrate for immobilizing aptamer strands. The measurements of Aβ were performed via differential pulse voltammetry (DPV), and the aptasensor detected the analyte in a linear range from 0.1pgmL-1 to 1ngmL-1, with an estimated limit of detection (LOD) of about 0.088pgmL-1 (S/N = 3). The aptasensor showed sufficient stability (11days), reversibility (three times), and reproducibility (five times re-fabrication with relative standard deviation (RSD): 1.27). The potential interfering agents showed negligible impact on the sensing performance. Finally, the application of the aptasensor was evaluated in the presence of 10 serum samples, and the recovery values were from 93 to 110.1%.

Effect of MWCNT on the properties of NCF-CFP hybrid composite fabricated via vacuum infusion

This work is an attempt to evaluate the effect of multi-wall carbon nanotube (MWCNT) reinforcement on the properties of non-crimp fabric (NCF) carbon fiber-reinforced polymer hybrid composite (CFRP). MWCNT NCF-CFRP plates were produced by vacuum infusion. Epoxy-MWCNT mixtures were prepared by adding a surfactant, Triton-X 100, and ethanol and mixing ultrasonically. The plates were subjected to thermal and electrical conductivity, DSC and FT-IR characterizations, and tensile testing. SEM image analyses evaluated tensile fracture surfaces. Results showed that 0.5 wt% MWCNT-reinforced nanocomposite samples exhibited better tensile properties than pure NCF-CFRP composites and other nanocomposite samples. The 1.5% MWCNT reinforced sample was the best conductor at all temperatures. The temperature increases also increase the conductivity. However, the conductivity value of 0.5% MWCNT reinforced material increased significantly at low frequencies such as 100–10,000 Hz. The heat reaction of the 0.5 wt% MWCNT nanocomposite was also a bit higher than that of 1–1.5 % wt MWCNT nanocomposites, indicating a decrease in the cure.

Enhanced photoelectrochemical water splitting in ternary layered chalcogenide ZnIn2S4 coupled with MWCNT

Layered hexagonal zinc indium sulfide coupled with multiwalled carbon nanotubes (MWCNT/H-ZnIn2S4) nanocomposites were prepared via using the hydrothermal method and investigated its photoelectrochemical (PEC) water-splitting properties. A series of MWCNT/H-ZnIn2S4 nanocomposites with different concentrations of MWCNT have been synthesized. The effects of the addition of different concentrations of MWCNT on the PEC performance of H-ZnIn2S4 material are studied. The outcomes showed that the maximum value of photocurrent density is obtained for 20 wt% MWCNT/H-ZnIn2S4, which is ∼3.8 times higher as compared to the H-ZnIn2S4 photoanode under visible light illumination. The enhancement in the current density is because of the electron-accepting behavior of MWCNT that helps in the effective separation and transfer of charges at the interface. The ability of MWCNT to accept and transport electrons offers a better path to regulate the movement of photogenerated charge carriers, extending the lifetime of the photogenerated charges produced in the semiconductors. A plausible mechanism for observed enhanced PEC activity of MWCNT/H-ZnIn2S4 nanocomposites is provided, which is supported by impedance spectroscopy and Mott-Schottky results.

The comparative study on microstructure and magnetic properties of cobalt ferrite/MWCNTs nanocomposite prepared using mechanical mixing and hydrothermal routs

The mechanical mixing (MM) and hydrothermal are known as prevalent and facile synthesis methods of the nanocomposite. In this research, the cobalt ferrite/ multi-wall carbon nanotubes (CF/MWCNTs) nanocomposites synthesized by these methods and microstructure and magnetic properties were investigated. The nanocomposites were characterized using X-ray diffraction (XRD), Field emission electron microscope (FESEM), Raman spectroscopy, thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and vibration sample magnetometer (VSM). Furthermore, the specific surface area of prepared nanocomposite was measured by the Brunauer-Emmett-Teller (BET) method. The single-phase cobalt ferrite without any impurities was observed in XRD patterns. The samples’ mean crystallite size was calculated by the Williamson –Hall and Rietveld methods which show that samples prepared by hydrothermal procedure has a larger crystallite size. Also, the obtained nanocomposites by both methods have a suitable phase distribution of CF nanoparticles and MWCNTs according to the FE-SEM micrographs. Moreover, the maximum magnetization (Mmax) for samples prepared by MM and hydrothermal methods were 35.6 and 49.5 emu/g, respectively. It is noteworthy that the Mmax values increase by 13.5 emu/g for sample synthesized by hydrothermal method compare to MM preparation. The results revealed that the presence of MWCNTs in the synthesis medium leads to cobalt ferrite nanoparticle growth and thus improves the magnetic properties.

Nanoadditives induced enhancement of thermal energy storage properties of molten salt: Insights from experiments and molecular dynamics simulations

Current concentrated solar power (CSP) plants use molten salts as heat storage and heat transfer medium. The thermal property enhancement of molten salts can increase the efficiency and lower the investment cost of CSP plants. In this study, the experiments and molecular dynamics (MD) simulations were employed to investigate the effect of doping Al2O3, SiO2 nanoparticles or multi-walled carbon nanotubes (MWCNTs) on the specific heat capacity (SHC) of ternary carbonate salt. The results show that the SHC of molten salt can be enhanced by adding nanoadditives. The addition of MWCNTs has the largest SHC enhancement in both solid and liquid states. Based on MD simulations, the radial distribution functions, number density distribution and vibrational density of states were further analyzed to reveal the effect of nanoadditive, base salt and interface thermal resistance between them on SHC at different temperatures. It is found that the nanoadditive agglomeration, the ion spacing of base salt, and the thermal resistance between base salt and nanoadditive is independent on temperature and cannot result in the enhanced SHC of liquid nanocomposites. Moreover, the thickness of interfacial layer changes with temperature. The thicker interfacial layer leads to the higher SHC of liquid nanocomposites. The interfacial layer also has a decisive influence on SHC of solid nanocomposites. The scanning electron microscopy images show that the layered, needle-like, and network-like interfacial layers are observed in Al2O3, SiO2 and MWCNT nanocomposites, respectively. The present findings are helpful to understand the mechanisms governing thermal energy storage, and provide guidelines for the performance optimization of molten salt based nanocomposites.

Ultrasonic-assisted of TiO2-MWCNT nanocomposite with advanced photocatalytic efficiency for elimination of dye pollutions

Nanocomposites of titanium dioxide (TiO2) and multi-wall carbon nanotubes (MWCNTs) were successfully synthesized (TiO2-MWCNTs) from MWCNTs and titanium tetrachloride (TiCl4) as starting precursors using ultrasonic-assisted technique. The impact of the different weight percentages of MWCNTs (1, 3, 5, and 7 wt%) on TiO2 optical, structural, and morphological properties were investigated. Subsequently, the photocatalytic activity was assessed by organic dyes degradation such as methylene Blue (MB) and rhodamine B (RhB) under ultraviolet (UV) light exposure. The characterization of synthesized materials demonstrated the anatase phase formation in both pure TiO2 and the TiO2-MWCNTs nanocomposite, according to X-ray diffraction analysis. The morphology analysis of TiO2-MWCNTs nanocomposites using FESEM and TEM confirmed the uniform dispersion of MWCNTs with an exterior diameter of 12–16 nm within the TiO2 matrix. The BET measurement of the sample's specific surface areas identified that the MWCNTs addition resulted in the increase of surface area from 76.34 to 194.35 m2 g−1 for pure TiO2 and TiO2/7 wt% MWCNTs, respectively. Furthermore, TiO2/7 wt% MWCNTs nanocomposite had lower optical bandgap energy and higher photocatalytic performance as compared to the pure TiO2. The photodegradation efficiency of TiO2/7 wt% MWCNTs nanocomposite increased from 63.63 % to 92.36 % for MB and 71.56 % to 94.13 % for RhB compared to pure TiO2, after 60 min UV light exposure.

Physical-Mechanical and Electrical Resistivity Properties of Cementitious Mortars Containing Fe3O4-MWCNTs Nanocomposite

Recent growth in materials science and engineering technologies has pushed the construction industry to engage in new applications, such as the manufacturing of smart and electrically conductive products. Such novel uses of conductive construction materials would potentially allow their use in conjunction with various fields, such as those referred to as “Industry 4.0.” The following study uses iron oxide (Fe3O4)-multi-walled carbon nanotubes (MWCNTs) nanocomposites synthesized by chemical vapor deposition (CVD) and incorporated into the cementitious mortars as a substitute for sand at 1, 2, and 3% ratios to enhance the electrical conductivity. Results reveal that the electrical resistivity of cementitious composites decreases (due to the increase in electrical conductivity) from 208.3 to 61.6 Ω·m with both the Fe3O4-MWCNTs nanocomposites ratio and the increasing voltage. The lowest compressive strengths at 7 and 28 days are 12.6 and 17.4 MPa for specimens with 3% Fe3O4-MWCNTs and meet the standards that comply with most applications. On the other hand, the highest porosity was reached at 26.8% with a Fe3O4-MWCNTs rate of 3%. This increase in porosity caused a decrease in both the dry unit weight and ultrasonic pulse velocity (from 5156 to 4361 m/s). Further, it is found that the incorporation of Fe3O4-MWCNT nanocomposites can have a negative effect on the hardening process of mortars, leading to localized air cavities and an inhomogeneous development of cementing products. Nonetheless, the improvement of the electrical conductivity of the samples without significantly compromising their physico-mechanical properties will allow their use in various fields, such as deicing applications with low-voltage electric current.

Effect of temperature on the electrical and electromechanical properties of carbon nanotube/polypropylene composites

The effect of temperature on the electrical and electromechanical (piezoresistive) properties of composite films made of multiwall carbon nanotubes (MWCNTs) and polypropylene is investigated. The electrical response to temperature in alternating current (AC, i.e. thermoimpedance) showed higher sensitivity than in direct current (DC, thermoresistivity) and is influenced by frequency (f). The sensitivity factor in DC reached 1.07 %°C−1, while in AC at 100 Hz was 2.7 % C−1 for the impedance modulus for 4 wt.% MWCNT nanocomposites . The electrical properties of the nanocomposites in AC investigated through broadband dielectric spectroscopy exhibited a resistive-capacitive behavior with a transition at f ∼104 Hz. Temperature also showed a strong influence on the piezoresistive response of the nanocomposites, showing a 10% increase in the piezoresistive sensitivity at 50 °C with respect to the response at 25 °C, and an important decrease in sensitivity at 100 °C for small (<3%) strains. The influence of temperature on the electrical and electromechanical responses investigated herein may assist in further developments of smart temperature-sensing materials, and in developing thermal compensation factors to properly calibrate piezoresistive/piezoimpedance responses for strain measurements.

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.

Probing the Electro-Chemical and Thermal Properties of Polyaniline/MWCNT Nanocomposites

The tremendous interest for robust, clean energy storage devices to comprehend the growing needs of modern gadgets has led to exploration of materials having unprecedented electrochemical and interfacial properties. Here, the present study deals with the synergistic effects of multi walled carbon nanotubes and polyaniline nanocomposites on the electro-chemical and thermal properties for wide-range of applications. The microstructural, structural, and optical characterizations have been evaluated through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis spectrophotometry. The thermal stability of the product was also studied through thermal gravimetric analysis (TGA) and the room temperature electrical conductivity was also measured. An exceptional enhancement in thermal stability and conductivity has been observed apparently due to interfacial properties of polyaniline (PANI) and multiwalled carbon nanotubes (MWCNTs). Further, in present study we are going to report a comparative analysis of thermal and electrical properties of PANI/MWCNT nanocomposites with different loadings of MWCNTs. The room temperature conductivity as calculated for 1%, 2%, 4% and 8% MWCNT loading is around 2.019, 3.075, 4.48, 8.73 S/cm respectively. The mechanism for thermal and electrical enhancements in PANI-coated MWCNT nanocomposites is also expounded.

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.