Multi-walled Carbon Nanotubes Nanocomposites Research Articles

An efficient voltammetric sensing platform for trace determination of Norfloxacin based on nanoplate-like α-zirconium phosphate/carboxylated multiwalled carbon nanotube nanocomposites

Norfloxacin (NOR) residues pose a potential threat to our health and ecosystem, so it is highly urgent to develop a simple but accurate method for NOR determination. Therefore, an efficient voltammetric sensing platform was constructed for trace detection of NOR based on nanoplate-like α-zirconium phosphate/carboxylated multiwalled carbon nanotubes (α-ZrP/CMWCNT). The physiochemical characteristics of α-ZrP/CMWCNT were scrutinized using various microscopic, spectroscopic, and electrochemical means. In order to pursuit higher voltammetric responses, detection conditions of NOR such as accumulation potential, accumulation time and buffer pH, were explored comprehensibly. The α-ZrP/CMWCNT enlarged the electrochemically active surface area and lowered the charge transfer resistance. Owing to the synergistic interactions between nanoplate-like α-ZrP NPs and CMWCNTs, the α-ZrP/CMWCNT boosted the voltammetric response signals and reduced the over-potential of NOR. Consequently, the α-ZrP/CMWCNT demonstrated remarkably catalytic activity for NOR electrooxidation, with two broad linear detection ranges (0.01–0.1 μM; 0.1–10.0 μM) and a low detection limit (2.8 nM). The α-ZrP/CMWCNT modified glassy carbon electrode (GCE) exhibited strong anti-interfering ability even in excess of other antibiotics and common metal ions, and maintained robust response peaks up to two weeks. The α-ZrP/CMWCNT/GCE realized accurate determination of NOR from complicated matrices at trace levels with good recoveries (99.00–104.40 %).

(Digital Presentation) Anelasticity, Mechanical Spectroscopy, Internal Friction in Radiation and Structural Functionalized Nanocomposites of Multiwalled Carbon Nanotubes and Polyamide, Polyvinylchloride, Polyethylene, SiO2

Experimental Methods Ultrasound (US) impulse-phase method using computerized “KERN-4” with frequencies f┴ ≈ 0,7 MHz and f║ ≈ 1 MHz was used [1,2]. The measured velocity error was equal to ΔV/V ≈ 1,5%. Results and Discussion The influencing of ultrasonic deformation εUS was researched on mechanical properties of nanocomposite. The important value is in position of formation in the polymeric matrix of molecular structures, as multiwalled carbon nanotubes serve as the centers of crystalline phase nanocomposite origin. Amplitude-dependent internal friction (ADIF) measurement can be used as the highly sensitive method of monitoring the nanoplastic deformation eND of nanocomposites. ADIF measurement makes it possible to record the moment of dislocation segments LC separation from stoppers. Internal friction (IF) is caused by various relaxation processes that are related to nanocomposites structure defectiveness. Even rather small strain can collect up in non-ideal nanocomposites, changing their anelastic and elastic characteristics. One of the ways to purposefully change the properties of multiwalled carbon nanotubes in order to use them in nanoelectronics is to introduce impurities of other elements. It was found that as the result of the structural defect annealing IF background Q0 -1 significantly decreases during measuring of IF temperature dependences Q-1(T), which indicates the improvement of nanocomposite structure. The samples were prepared by ultrasonic dispersion using digital ultrasonic (US) bath CE-6200A with power W = 70 W at frequency f ≈ 42 kHz [1,2]. Illustration of the window for processing data of quasilongitudinal elastic waves velocity measuring V║ = 3244 ± 10 m/sec m/sec in nanocomposite polyamide (PA-6) (NH(CH2)5CO)n + 0,1% multiwalled carbon nanotubes (MCNT) by by pulse-phase US method at frequency f║ ≈ 1 MHz after electron irradiation with dose De- ≈ 10 MRad with energy Ee- ≈ 2,0 MeV is represented in Fig. 1. Fig.1. Illustration of the window for processing data of quasilongitudinal elastic waves velocity measuring V║ = 3244 m/sec in nanocomposite polyamide (PA-6) (NH(CH2)5CO)n + 0,1% MCNT by pulse-phase US method at frequency f║ ≈ 1 MHz after electron irradiation with dose De- ≈ 10 MRad.Poisson coefficient μ and elastic modulus E completely characterize the elastic properties of polymer nanocomposite. Poisson coefficient μ - elastic value of ratio of relative transversal compression e^ to relative longitudinal lengthening e║ [1]. One oscillator produces 3 waves: 1 longitudinal and 2 transversal. Debye temperature θD was determined after the formula [2], where kB - Boltzmann constant, h - Plank constant, NA - Avogadro number, A - middle gram-molecular mass, V║ - quasilongitudinal US velocity, V┴ - quasitransversal US velocity.Complex elastic modulus of nanocomposite polyamide-6 (PA-6) (NH(CH2)5CO)n + % MCNT E* is equal to the sum of elastic dynamic modulus E’ = rV║ 2 and loss modulus E” = E’d [2], where δ - logarithmic decrement of US attenuation, ρ - nanocomposite density, V║ - longitudinal US elastic waves velocity, Q-1 - internal friction, where α - US attenuation coefficient, λ - US wavelength, f - US frequency. Internal friction is equal Q-1 = δ/π. The logarithmic decrement of attenuation δ of US oscillations with amplitude A = A0e- d x is equal: δ = ln(An+1/An). Conclusions The presence of the strong interaction for nanocomposite between polyamide-6 (NH(CH2)5CO)n and multiwalled carbon nanotubes was confirmed.The increase of the nanocomposite crystallinity degree at growth of multiwalled carbon nanotubes concentration filling with the nanotubes of matrix results in the decline of content of organized phase.The phenomenon of change of Poisson coefficient m, Debye temperature θD, dynamic elastic modulus E’ = rV║ 2, dynamic shear modulus G = rV^ 2 under the influence of radiative electronic e- radiation is caused by the appearance of primary radiation defects (RD). As the result of interdefect interactions primary RD form secondary RD. Acknowledgments This work has been supported by the Ministry of Education and Science of Ukraine: Grant of the Ministry of Education and Science of Ukraine for the prospective development of the scientific direction “Mathematical sciences and natural sciences” at Taras Shevchenko National University of Kyiv. References Onanko, A.P., Kuryliuk, V.V., Onanko, Y.A. et al. Features of inelastic and elastic characteristics of Si and SiO2/Si structures. Journal of Nano- and Electronic Physics13(5), 05017(5) (2021).Onanko, A.P., Kuryliuk, V.V., Onanko, Y.A. et al. Mechanical spectroscopy and internal friction in SiO2/Si. Journal of Nano- and Electronic Physics14(6), 06029(7) (2022). Figure 1

Mussel-Inspired Multiwalled Carbon Nanotube Nanocomposite for Methyl Orange Removal: Adsorption and Regeneration Behaviors.

A mussel-inspired multiwalled carbon nanotube (MWCNT) nanocomposite (MWCNTs@CCh-PEI) was prepared by the co-deposition of catechol (CCh)/polyethyleneimine (PEI) and modification of MWCNTs for the efficient removal of methyl orange (MO). The effects of MO solution pH, contact time, initial MO concentration, and temperature on the adsorption capacity of MWCNTs@CCh-PEI were investigated. The results indicate that the adsorption capacity of MWCNTs@CCh-PEI was two times higher than that of pristine MWCNTs under the same conditions. The adsorption kinetics followed the pseudo-second-order model, suggesting that the adsorption process was chemisorption. The adsorption isotherm shows that the experimental data were fitted well with the Langmuir isotherm model, with a correlation coefficient of 0.9873, indicating that the adsorption process was monolayer adsorption. The theoretical maximum adsorption capacity was determined to be 400.00 mg·g-1. The adsorption thermodynamic data show that the adsorption process was exothermic and spontaneous. More importantly, the adsorption capacity of MWCNTs@CCh-PEI showed no significant decrease after eight reuse cycles. These results demonstrate that MWCNTs@CCh-PEI is expected to be an economical and efficient adsorbent for MO removal.

A Biosensor for Simultaneous Detection of Epinephrine and Ascorbic Acid Based on Fe(III)-Polyhistidine-Functionalized Multi-Wall Carbon Nanotube Composites.

Epinephrine (EP) is a very important chemical transmitter in the transmission of nerve impulses in the central nervous system of mammals. Ascorbic acid (AA) is considered to be the most important extracellular fluid antioxidant and has important antioxidant properties in the cell. In this study, a series of transition metal-polyhistidine-carboxylated multi-wall carbon nanotube nanocomposites were synthesized, and their simultaneous catalytic effects on epinephrine and ascorbic acid were investigated. The results showed that nanocomposites based on iron ions had the highest catalytic activity. The prepared biosensor expressed high selectivity toward EP and AA with LOD values of 0.1 μΜ (AA) and 0.01 μΜ (EP), and sensitivity values of 4.18 μA mM-1 with a range of 0.001-5 mM (AA), 50.98 μA mM-1 with a range of 0.2-100 μM (EP), and 265.75 μA mM-1 with a range of 0.1-1.0 mM (EP). Moreover, it showed good stability, good repeatability and high selectivity in real sample detection. This work is a reference for the design of new electrochemical enzyme-free biosensors and the detection of biomarkers.

Highly selective ammonia gas sensor at room temperature based on MoO3/MWCNT-9 nanocomposites

Herein, a resistive gas sensor based on Molybdenum tri oxide (MoO3)/ 9 % mass fraction of multi-walled carbon nanotubes (MWCNTs-9) nanocomposites was developed by hydrothermal method to detect NH3 gas at room temperature. According to the findings, outstanding resistance change rate of 187.5 % was observed in MoO3/MWCNT-9 sensor when exposed to 100 ppm NH3 at room temperature (25 °C). In contrast, 8.2 % response rate was recorded for pure MoO3 sensor when exposed to same condition and the response value of newly fabricated sensor was improved by about 22.9 times to unalloyed MoO3. In addition, the nanocomposite sensor consisting of MoO3/MWCNT-9 had demonstrated excellent selectivity, repeatability, and a high level of sensitivity in detecting low concentrations of NH3 at low temperature. During experiment when the sensor desorbed NH3 gas at room temperature, a certain instantaneous voltage was applied, which greatly reduces the sensor’s resistance recovery time to 90 s. MWCNTs’s doping decreased the operating temperature of MoO3 and showed good gas sensitivity at room temperature. Finally, the results reveal that MoO3/MWCNT-9 nanocomposite-based sensor can be fruitful in the field of NH3 monitoring.

Heterogenization of Ionic Liquid on Multiwalled Carbon Nanotubes for Lead(II) Ion Detection.

The presence of lead(II) ion poses a significant threat to water systems due to their toxicity and potential health hazards. The detection of Pb2+ ions in contaminated water is very crucial. The ionic liquid functionalized multiwalled carbon nanotubes (IL@MWCNT) nanocomposite was fabricated using ionic liquid (IL) 1-methyl-3-(4-sulfobutyl)-imidazolium chloride and multiwalled carbon nanotubes (MWCNTs) for detection of lead(II) ions. It is a novel method to heterogenize the layer of IL on the surface of MWCNTs. The XPS and FTIR analyses confirm that the ionic liquid is not decomposed during annealing process. Moreover, the XRD analysis shows the presence of MWCNTs and carbon quantum dots (CQDs). The HRTEM results exhibit the aggregation of MWCNTs with IL, and formation of small distorted round shaped flakes of CQDs. Further, the successful heterogenization of IL on the surface of MWCNTs is also confirmed by TGA-DSC analysis. The quenching phenomenon of nanocomposite was observed by UV-Visible spectroscopy. The nanocomposite exhibits high performance for the selective detection of lead(II) ions in comparison to other metal ions. The presence of lead(II) ions eventually reduced the intensity of absorption. A limit of detection (LOD) of 9.16 nM was attained for Pb2+ ions in a concentration range of 0-20 nM.

Efficient and environmentally friendly uric acid voltametric sensor based on Ni-MOF and carboxylated multi-walled carbon nanotubes nanocomposites

Uric acid (UA) levels are significant in the monitoring of human health, making their detection very important. In this paper, a simple and innovative electrochemical method for the detecting UA was established, using a sensing platform based on hybrid electrodes of Nickel-Metal Organic Framework (Ni-MOF) and carboxylated multi-walled carbon nanotubes (MWCNTs-COOH). Detailed investigations into the electrocatalytic activity of Ni-MOF/MWCNTs-COOH/GCE for The Ni-MOF/MWCNTs-COOH exhibited remarkable catalytic activity for UA oxidation. The detection limit was 0.005 μM, with a sensitivity calculation result of 6.377 µA µM−1, and a wide linearity interval (0.03–10 μM, 10–300 μM). Utilizing its high sensitivity and selectivity, this sensor was used for the measurement of UA in biological fluids, including human serum and urine samples, recovery amounts being 96.6–100.8 %, and 98.9–101.3 %. This work is highly significant; offering new perspectives for the application of Ni-MOF based chemical sensors in the realms of environmental monitoring and healthcare.

Preparation, characterization, and properties of acrylonitrile butadiene styrene / multi walled carbon nanotubes nanocomposites

Preparation, characterization, and properties of acrylonitrile butadiene styrene / multi walled carbon nanotubes nanocomposites

Thermal plasma synthesis of Si-multi walled carbon nanotube nanocomposite as an anode for lithium-ion batteries

The Si-MWCNT (multi-walled carbon nanotube) nanocomposite, which is considered a promising replacement for graphite as an anode material for lithium-ion batteries, was prepared using a triple DC thermal plasma jet system. We used micron-size silicon powder and MWCNT powder as raw materials. We varied the main parameters by mixing silicon and MWCNTs or individually injected into the plasma jet and adjusting the mass ratio to 2:1 and 1:2. The location of injection for the raw materials played a critical role in the formation of Si-MWCNT nanocomposites as the temperature at the injection site has a significant impact on the vaporization of silicon and sublimation of carbon nanotubes. Additionally, it was influenced by efficient heat transfer of silicon and the structural change of MWCNT. As a result, the Si-MWCNT nanocomposite was easily produced under separate injection conditions, and silicon nanoparticles of 20 nm or less were attached to the surface of the MWCNT. We evaluated the electrochemical performance of the synthesized material by assembling a CR2032-type coin cell using it as an anode electrode material.

Solid‐contact ion‐selective sensor for the direct determination of procyclidine HCl and application of in‐line dissolution profiling of its tablets

AbstractThe ability to obtain accurate analytical results without sample pre‐treatment or derivatization is a key element for an eco‐friendly method of analysis. In this work, green electro analytical method was developed and evaluated for the selective determination of the anti‐cholinergic drug Procyclidine Hydrochloride in both pure and dosage forms as well as in dissolution medium without sample pre‐treatment. Firstly, screening of four ionophore‐doped polyvinyl chloride‐based membranes were conducted to detect the one with highest affinity towards the studied drug. Accordingly, calix[4]arene‐doped membrane exhibited the optimum results. Then optimization was carried out by designing screen‐printed and glassy carbon solid‐contact ion‐selective electrodes with multiwall carbon nanotube and graphene nanocomposite as ion to electron transducers. The fabricated screen‐printed sensor with graphene nanocomposite was characterized according to IUPAC recommendations. It acquired the fastest and most stable response, along with thermal stability up to 30 °C. It also displayed a slope of 43.9±0.2 mV/decade in a pH range of 2–5. The proposed sensor successfully obtained a linear range of 1×10−5–1×10−2 M and the theoretical limit of detection was 6.3×10−6 M. Finally, it was used in applications such as in‐line dissolution monitoring and quantification of procyclidine in its dosage form without prior sample pre‐treatment or derivatization steps. Furthermore, the graphene nanocomposite transducer has been imaged by Scanning Electron Microscope (SEM).

Fabrication of a Molybdenum Dioxide/Multi-Walled Carbon Nanotubes Nanocomposite as an Anodic Modification Material for High-Performance Microbial Fuel Cells.

A nanocomposite of multi-walled carbon nanotubes (MWCNTs) decorated with molybdenum dioxide (MoO2) nanoparticles is fabricated through the reduction of phosphomolybdic acid hydrate on functionalized MWCNTs in a hydrogen-argon (10%) atmosphere in a tube furnace. The MoO2/MWCNTs composite is proposed as an anodic modification material for microbial fuel cells (MFCs). MWCNTs have outstanding physical and chemical peculiarities, with functionalized MWCNTs having substantially large electroactive areas. In addition, combined with the exceptional properties of MoO2 nanoparticles, the synergistic advantages of functionalized MWCNTs and MoO2 nanoparticles give a MoO2/MWCNTs anode a large electroactive area, excellent electronic conductivity, enhanced extracellular electron transfer capacity, and improved nutrient transfer capability. Finally, the power harvesting of an MFC with the MoO2/MWCNTs anode is improved, with the MFC showing long-term repeatability of voltage and current density outputs. This exploratory research advances the fundamental application of anodic modification to MFCs, simultaneously providing valuable guidance for the use of carbon-based transition metal oxide nanomaterials in high-performance MFCs.

Electrochemical sensor based on nickel selenide/hydroxylated multiwalled carbon nanotubes nanocomposites for sensitive detection of maltol

An effective electrochemical sensor based on electrodeposition of nickel selenide nanoparticles (Ni3Se4) on the surface of a glass carbon electrode (GCE) modified with hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) has been successfully developed for determination of maltol. The chemical composition and morphology of Ni3Se4/MWCNTs-OH composites are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) are employed to investigate the electrochemical behavior of maltol at Ni3Se4/MWCNTs-OH/GCE. Consequently, electrochemical sensor based on Ni3Se4/MWCNTs-OH/GCE for detection of maltol displays good electrocatalyst performance. The obtained oxidation peak current of maltol at Ni3Se4/MWCNTs-OH/GCE increases linearly with the increase in concentration of maltol in the range of 0.1 μM–2000 μM, and the calculated detection limit (LOD) is 17.5 nM (S/N = 3). In addition, the fabricated electrochemical sensor shows satisfactory stability, reliable reproducibility and excellent selectivity, and is successfully used to detect maltol in real samples with acceptable accuracy.

Tube-Like Copper Cobalt Oxide Anchored with Multiwalled Carbon Nanotube Nanocomposite Modified Glassy Carbon Electrode for the Electrochemical Detection of Nilutamide

Developing a precise and effective method to detect Nilutamide (NIL) is essential due to its contamination of the environment, which poses significant risks to human health and the biosphere. In this study, we employed a simple hydrothermal technique to create a nanocomposite of CuCo2O4 (copper cobalt oxide) and multi-walled carbon nanotube (MWCNT), which was then anchored onto a glassy carbon electrode for NIL detection. Various spectroscopic techniques were employed to confirm the structure of the nanomaterial, and its electrochemical properties were examined using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. The CuCo2O4/MWCNT nanocomposite-modified electrode exhibited a wide linear detection range from 0.01 to 170 μM, a high sensitivity of 1.50 μA μM−1 cm−2, a low detection limit of 0.01 μM, outstanding stability, repeatability, and practical applicability for NIL detection.

Resilient forward osmosis membranes against microplastics fouling enhanced by MWCNTs/UiO-66-NH2 hybrid nanoparticles

The escalating presence of microplastics (MPs) in wastewater necessitates the investigation of effective tertiary treatment process. Forward osmosis (FO) emerges as an effective non-pressurized membrane process, however, for the effective implementation of FO systems, the development of fouling-resistance FO membranes with high-performance is essential. This study focuses on the integration of MWCNT/UiO-66-NH2 as metal-organic frameworks (MOFs) and multi-wall carbon nanotubes (MWCNT) nanocomposites in thin film composite (TFC) FO membranes, harnessing the synergistic power of hybrid nanoparticles in FO membranes. The results showed that the addition of MWCNT/UiO-66-NH2 in the aqueous phase during polyamide formation changed the polyamide surface structure, and enhanced membranes’ hydrophilicity by 44%. The water flux of the modified FO membrane incorporated with 0.1 wt% MWCNTs/UiO-66-NH2 increased by 67% and the reverse salt flux decreased by 22% as in comparison with the control membrane. Moreover, the modified membrane showed improved antifouling behavior against both organic foulant and MPs. The MWCNT/UiO-66-NH2 membrane experienced 35% flux decline while the control membrane experienced 65% flux decline. This proves that the integration of MWCNT/UiO-66-NH2 nanoparticles into TFC FO membranes is a viable approach in creating advanced FO membranes with high antifouling propensity with potential to be expanded further to other membrane applications.

Electrochemical detection of heavy metal ions in water using MWCNT/ZnO nanocomposite

A nanocomposite of multi-walled carbon nanotubes (MWCNTs) decorated with zinc oxide nanoparticles (ZnO NPs) was fabricated via an in-situ hydrothermal approach and implemented as a modified electrode for stripping voltammetric detection of dissolved heavy metal ions. The MWCNT/ZnO exhibited a high specific surface area of 53 m2/g and charge transfer conductivity amplified to 26 S/cm. By square wave voltammetry, the nanocomposite sensor achieved wide linear detection of Cu(II) from 1 to 800 ppb, Pb(II) from 5 to 1000 ppb, and Hg(II) from 1 to 900 ppb, along with low limits of detection reaching 0.8, 1.2, and 0.7 ppb, respectively. The 3–5X enhanced sensitivity versus an unmodified screen-printed carbon electrode confirms performance gains supplied by the tailored hybrid interface. Selectivity testing produced distinct, well-resolved oxidation peaks for each metal ion target that remained unaffected by high off-target concentrations of Mn(II), Co(II), and Fe(III) interferents. Accurate spike recoveries between 95% and 102% were obtained from quantifying ternary mixtures across various Cu(II):Pb(II):Hg(II) compositions, substantiating the capability for simultaneous multianalyte analysis. The simple preparation, high sensitivity and selectivity, and accuracy for direct water testing validates the nanocomposite as a practical portable sensor for on-site toxic heavy metal detection.

Nano cerium oxide loaded magnetic multi-walled carbon nanotubes nanocomposite for anti-cancer and anti-bacterial applications

Our study describes the hydrothermal synthesis of CeO2 and Fe3O4 nanoparticles (NPs), and CeO2-loaded magnetic multi-walled carbon nanotubes (MWCNT) nanocomposites (NCs). The obtained CeO2-MMCNTs NC was physicochemically characterized by XRD, FTIR, FESEM, EDX, and UV–visible spectroscopy to assess the NC's crystalline size, functional group, shape, elemental content, and optical characteristics. Further, the disc diffusion method and bacterial reduction assay were used to assess the antibacterial activity of the CeO2-MMCNTs NC. The results showed that NC exhibited better antibacterial activity than cerium oxide NPs. The antioxidant activity of NC was also assessed using the DPPH test, and the findings revealed that the CeO2-MMCNTs NC had stronger scavenging activity than cerium oxide NPs. Next, the MTT test was used to assess the anticancer activity of the NC, and the findings indicated that the CeO2-MMCNTs NCs killed human colon cancer cells with a low IC50 value. These results suggested that CeO2-MMCNTs NC can be used for biomedical applications.

A facile, environmentally-benign, green and a novel synthesis of tert-butyl-quinolines by using Fe3O4-MWCNT@CeO2 as recyclable catalyst

The aim of the present work is to examine the catalytic activity of ceria (CeO2) supported on a nano-composite of iron oxide and multi-walled carbon nanotubes (Fe3O4-MWCNT). A simple impregnation protocol was used to synthesize Fe3O4-MWCNT@CeO2 nano-composite, and a diversity of analytical techniques (including XRD, BET, TGA, SEM, TEM, and EDS) were used to thoroughly describe the catalyst material. The CeO2 supported on Fe3O4-MWCNT were found to be uniformly distributed throughout the nano-composite, irregular spherical in shape, and ranged in size from 5 to 15 nm, according to high-resolution TEM image. Afterwards, the synthesis of novel tert-butyl-quinoline analogues via a multi-component condensation comprising substituted aldehydes, dimedone, 3°-butylacetoacetate, and NH4OAc was used to evaluate the catalytic performance of the Fe3O4-MWCNT@CeO2 nano-composite. Their large specific surface area, porosity, unique exposed surfaces, and stability all contribute to their effectiveness. The catalyst's extremely active surfaces are highlighted by the notably high turn-over frequency. Thus, using ethanol as the green solvent, we suggest an effective and reusable catalytic approach that works at mild reaction condition with excellent product yields (90–97 %). This makes that nano-composite inexpensive, safe for the environment, and very atom-efficient. When compared to existing commercial approaches, our protocol is found to be more sustainable and efficient.

Preparation and Characterization of Functionalized Multi-Walled Carbon Nanotubes (f-MWCNTs) Incorporated in Gelatin-Based Hydrogel Nanocomposites

This study prepared gelatin/functionalized multi-walled carbon nanotube (f-MWCNT) nanocomposites with different f-MWCNT concentrations using a simple solution casting method. For each f-MWCNT concentration of the gelatin/f-MWCNT nanocomposites, permittivity parameters were measured at five different locations on the sample surface. Cole–Cole graphs were obtained by plotting the imaginary permittivity as a function of the real permittivity. The Havriliak–Negami model was used to obtain the value of alpha, since the shape is a quasi-skewed semicircle. The average relaxation time was τ = 12.6 ps and was roughly constant with the addition of f-MWCNTs. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) images showed increased interactions between the carbon nanotubes and polymers.

Microfluidic paper-based analysis device applying black phosphorus nanosheets@MWCNTs-COOH: A portable and efficient strategy for detection of β-Lactoglobulin in dairy products

This study prepared a novel, portable and cost-effective microfluidic paper-based electrochemical analysis device (μ-PAD) using black phosphorus nanosheets@carboxylated multi-walled carbon nanotubes (BPNSs@MWCNTs-COOH) nanocomposites for β-lactoglobulin (β-LG) detection. At the appreciate ratio, the synthesized BPNSs@MWCNTs-COOH was demonstrated to not only serve as a high-quality substrate for the specific aptamer immobilization, but also improve the electron transfer capability of the sensing interface. The μ-PADs, utilizing BPNSs@MWCNTs-COOH and aptamer recognition, exhibited a wider detection range (10–1000 ng mL−1) and lower detection limit (LOD: 0.12 ng mL−1) for β-LG, and demonstrated enhanced specificity, satisfactory anti-interference ability and stability. When applied to the β-LG determination in dairy samples, the μ-PAD yielded β-LG concentrations highly correlated with those obtained using the HPLC method (R2: 0.9982). These results emphasized the reliable performance of the developed μ-PADs in β-LG allergen quantification, highlighting their potential as an efficient platform for the rapid screening of β-LG allergens.

High-Performance PEEK/MWCNT Nanocomposites: Combining Enhanced Electrical Conductivity and Nanotube Dispersion.

High-performance engineering thermoplastics offer lightweight and excellent mechanical performance in a wide temperature range. Their composites with carbon nanotubes are expected to enhance mechanical performance, while providing thermal and electrical conductivity. These are interesting attributes that may endow additional functionalities to the nanocomposites. The present work investigates the optimal conditions to prepare polyether ether ketone (PEEK)/multi-walled carbon nanotube (MWCNT) nanocomposites, minimizing the MWCNT agglomerate size while maximizing the nanocomposite electrical conductivity. The aim is to achieve PEEK/MWCNT nanocomposites that are suitable for melt-spinning of electrically conductive multifilament's. Nanocomposites were prepared with compositions ranging from 0.5 to 7 wt.% MWCNT, showing an electrical percolation threshold between 1 and 2 wt.% MWCNT (107-102 S/cm) and a rheological percolation in the same range (1 to 2 wt.% MWCNT), confirming the formation of an MWCNT network in the nanocomposite. Considering the large drop in electrical conductivity typically observed during melt-spinning and the drawing of filaments, the composition PEEK/5 wt.% MWCNT was selected for further investigation. The effect of the melt extrusion parameters, namely screw speed, temperature, and throughput, was studied by evaluating the morphology of MWCNT agglomerates, the nanocomposite rheology, and electrical properties. It was observed that the combination of the higher values of screw speed and temperature profile leads to the smaller number of MWCNT agglomerates with smaller size, albeit at a slightly lower electrical conductivity. Generally, all processing conditions tested yielded nanocomposites with electrical conductivity in the range of 0.50-0.85 S/cm. The nanocomposite processed at higher temperature and screw speed presented the lowest value of elastic modulus, perhaps owing to higher matrix degradation and lower connectivity between the agglomerates. From all the process parameters studied, the screw speed was identified to have the higher impact on nanocomposite properties.