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Search Results (1,621)

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15 pages, 6069 KiB  
Article
High-Efficiency Photoresponse of Flexible Copper Oxide-Loaded Carbon Nanotube Buckypaper Under Direct and Gradient Visible Light Illumination
by Lakshmanan Saravanan, Wei-Cheng Tu, Hsin-Yuan Miao and Jih-Hsin Liu
Processes 2025, 13(1), 188; https://doi.org/10.3390/pr13010188 - 10 Jan 2025
Viewed by 459
Abstract
This study used a direct dispersion and filtration technique to produce hybrid buckypaper (BP) composites of copper oxide nanoparticles (NPs) and entangled multiwalled carbon nanotubes (CNTs). The photocurrent generation of the BP sheets under two different (direct and gradient) illumination conditions was investigated [...] Read more.
This study used a direct dispersion and filtration technique to produce hybrid buckypaper (BP) composites of copper oxide nanoparticles (NPs) and entangled multiwalled carbon nanotubes (CNTs). The photocurrent generation of the BP sheets under two different (direct and gradient) illumination conditions was investigated by varying copper oxide loadings (10–50 wt%). The structure and morphology of the composites examined through X-ray diffraction and scanning electron microscopy (SEM) confirmed the presence of monoclinic cupric oxide nanoparticles in the CNT network. The difference in electrical resistivity between bulk-filled and surface-filled CuO-BP composites was assessed using the four-probe Hall measurement. The studies disclosed that the surface-loaded CuO on the CNT network demonstrated a superior ON and OFF response under the gradient illumination conditions with peak values of 17.69 μA and 350.04 μV for photocurrent and photovoltage, respectively. The significant photocurrent observed at zero applied voltage revealed the existence of a photovoltaic effect in the BP composites. An intense photoresponse was detected in the surface-filled sample CuO-BP composite in both illumination conditions. Additionally, at an illumination level of 150 W/m2, wavelength-dependent photovoltaic effects on pure BP were observed using red, green, and blue filters. Full article
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16 pages, 2145 KiB  
Article
Highly Selective Oxidation of 1,2-Propanediol to Lactic Acid Using Pd Nanoparticles Supported on Functionalized Multi-Walled Carbon Nanotubes
by Zhiqing Wang, Xiong Xiong, Aiqian Jin, Lingqin Shen and Hengbo Yin
Catalysts 2025, 15(1), 53; https://doi.org/10.3390/catal15010053 - 9 Jan 2025
Viewed by 304
Abstract
1,2-Propanediol, with its highly functionalized molecular structure and abundant availability, serves as a viable feedstock for high-value chemicals. The oxidation of 1,2-propanediol can potentially yield lactic acid, an important commodity chemical. Herein, we report the catalytic oxidation of 1,2-propanediol in the presence of [...] Read more.
1,2-Propanediol, with its highly functionalized molecular structure and abundant availability, serves as a viable feedstock for high-value chemicals. The oxidation of 1,2-propanediol can potentially yield lactic acid, an important commodity chemical. Herein, we report the catalytic oxidation of 1,2-propanediol in the presence of NaOH, using Pd nanoparticles (NPs) supported on various functionalized multi-walled carbon nanotubes (MWCNTs). Both single-factor experiments and the response surface methodology were employed to investigate the optimal operating parameters. It was found that nitrogen doping promotes strong metal–support interactions between the active components and the support. Under optimal reaction conditions (123 °C, 1.25 MPa O2 pressure, 4 h, and a NaOH/1,2-PDO molar ratio of 4.0), a high lactic acid yield of 68.3% was achieved using nitrogen-doped MWCNT-supported Pd nanoparticles as the catalyst. The selectivity for lactic acid decreased with increasing reaction time, temperature, NaOH/1,2-PDO molar ratio, and O2 pressure, while the conversion rate increased correspondingly. After five cycles, the conversion of 1,2-PDO slightly decreased to 76.2%, while the LA selectivity remained high at 84.9%. Additionally, the reaction pathway was further investigated, confirming the formation mechanism of lactic acid. Full article
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22 pages, 9323 KiB  
Article
Magnetic Field-Assisted Orientation and Positioning of Magnetite for Flexible and Electrically Conductive Sensors
by David Seixas Esteves, Amanda Melo, Sónia Alves, Nelson Durães, Maria C. Paiva and Elsa W. Sequeiros
Micromachines 2025, 16(1), 68; https://doi.org/10.3390/mi16010068 - 8 Jan 2025
Viewed by 379
Abstract
Magnetic field-assisted control of magnetite location is a promising strategy for developing flexible, electrically conductive sensors with enhanced performance and adjustable properties. This study investigates the effect of static magnetic fields applied on thermoplastic elastomer (TPE) composites with magnetite and multi-walled carbon nanotubes [...] Read more.
Magnetic field-assisted control of magnetite location is a promising strategy for developing flexible, electrically conductive sensors with enhanced performance and adjustable properties. This study investigates the effect of static magnetic fields applied on thermoplastic elastomer (TPE) composites with magnetite and multi-walled carbon nanotubes (MWCNT). The composites were prepared by compression moulding and the magnetic field was applied on the mould cavity during processing. Composites were prepared with a range of concentrations of magnetite (1, 3, and 6 wt.%) and MWCNT (1 and 3 wt.%). The effect of particle concentration on composite viscosity was investigated. Rheological analysis showed that MWCNTs significantly increased the composite viscosity while magnetite had minimal impact, ensuring stable processing and facilitating particle orientation under a static magnetic field. Particle orientation and electrical conductivity were evaluated for the composites prepared with different particle concentrations under different processing temperatures. Magnetic field application at 190 °C enhanced magnetite/MWCNT interactions, substantially reducing electrical resistivity while preserving thermal stability. The composites showed no degradation at 220 °C and above, demonstrating suitability for high-temperature applications requiring thermal resilience. Furthermore, magnetite’s magnetic response facilitated precise sensor positioning and strong adhesion to polyimide substrates at 220 °C. These findings demonstrate a scalable and adaptable approach for enhancing sensor performance and positioning, with broad potential in flexible electronics. Full article
(This article belongs to the Special Issue Feature Papers of Micromachines in 'Materials and Processing' 2024)
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17 pages, 4411 KiB  
Article
Study of Corrosion of Portland Cement Embedded Steel with Addition of Multi-Wall Carbon Nanotubes
by Miguel Angel Gómez-Aristizabal, Jhoan Mauricio Moreno-Vargas, Laura María Echeverry-Cardona and Elisabeth Restrepo-Parra
Materials 2025, 18(1), 210; https://doi.org/10.3390/ma18010210 - 6 Jan 2025
Viewed by 398
Abstract
In this study, we research the innovative application of multi-walled carbon nanotubes (MWCNTs) as corrosion inhibitors in Portland cement embedded steel. The physicochemical properties of the dispersion solutions were evaluated, varying the storage time, to analyze their effect on corrosion resistance. Using a [...] Read more.
In this study, we research the innovative application of multi-walled carbon nanotubes (MWCNTs) as corrosion inhibitors in Portland cement embedded steel. The physicochemical properties of the dispersion solutions were evaluated, varying the storage time, to analyze their effect on corrosion resistance. Using a dispersion energy of 440 J/g and a constant molarity of 10 mM, stable dispersions were achieved for up to 3 weeks. These dispersions were characterized using Raman spectroscopy, UV-Vis spectroscopy and Zeta potential spectroscopy to assess the stability and structural damage of the MWCNTs. These results show that the addition of MWCNTs not only reduces the porosity of the cement matrix, but also forms an effective barrier against chloride ion intrusion, protecting the reinforcing steel. This approach stands out for combining improved mechanical properties and significant corrosion resistance, representing a promising innovation in the development of more durable construction materials. Full article
(This article belongs to the Section Carbon Materials)
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30 pages, 10187 KiB  
Article
Characterization of Electrospun PAN Polymer Nanocomposite Membranes for CO2/N2 Separation
by Dirar Aletan and Jacob Muthu
J. Compos. Sci. 2025, 9(1), 21; https://doi.org/10.3390/jcs9010021 - 6 Jan 2025
Viewed by 370
Abstract
The focus of this study was to enhance the CO2 capture capabilities of polyacrylonitrile (PAN) nanocomposite membranes by reinforcing them with multi-walled carbon nanotubes (MWCNT) and silica (SiO2). These nanocomposite membranes were created using electrospinning technology, which produced nonwoven nanofiber [...] Read more.
The focus of this study was to enhance the CO2 capture capabilities of polyacrylonitrile (PAN) nanocomposite membranes by reinforcing them with multi-walled carbon nanotubes (MWCNT) and silica (SiO2). These nanocomposite membranes were created using electrospinning technology, which produced nonwoven nanofiber membranes. The nanoparticles were functionalized using Gum Arabic (GA) to improve the distribution and prevent agglomeration. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis were conducted to examine the functionalization of nanoparticles and their morphological structures. The membranes were experimentally characterized to obtain the CO2 absorption properties and also to evaluate CO2/N2 permeation properties compared to pure PAN membranes. The results showed that higher nanoparticle concentrations increased CO2 permeability while maintaining stable N2 permeability, ensuring favorable CO2/N2 selectivity ratios. The 4 wt.% MWCNTs nanocomposite membrane achieved the best CO2/N2 separation with a CO2 permeability of 289.4 Barrer and a selectivity of 6.3, while the 7 wt.% SiO2 nanocomposite membrane reached a CO2 permeability of 325 Barrer and a selectivity of 7. These findings indicate significant improvements in CO2 permeability and selectivity for the nanocomposite membranes compared to pure PAN membranes. The Maxwell mathematical model has been used to validate the experimental results. The experimental results of the CO2 separation properties of the nanocomposite membranes exceeded the predicted values by the mathematical models. This might be due to the well-dispersed nanoparticles and functional groups. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2024)
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18 pages, 3678 KiB  
Article
Development of a Novel Electrochemical Immunosensor for Rapid and Sensitive Detection of Sesame Allergens Ses i 4 and Ses i 5
by Huimei Li, Tian’ge Pan, Shudong He, Hanju Sun, Xiaodong Cao and Yongkang Ye
Foods 2025, 14(1), 115; https://doi.org/10.3390/foods14010115 - 3 Jan 2025
Viewed by 483
Abstract
Due to their lipophilicity and low content, the major sesame oleosin allergens, Ses i 4 and Ses i 5, are challenging to identify using conventional techniques. Then, a novel unlabeled electrochemical immunosensor was developed to detect the potential allergic activity of sesame oleosins. [...] Read more.
Due to their lipophilicity and low content, the major sesame oleosin allergens, Ses i 4 and Ses i 5, are challenging to identify using conventional techniques. Then, a novel unlabeled electrochemical immunosensor was developed to detect the potential allergic activity of sesame oleosins. The voltammetric immunosensor was constructed using a composite of gold nanoparticles (AuNPs), polyethyleneimine (PEI), and multi-walled carbon nanotubes (MWCNTs), which was synthesized in a one-pot process and modified onto a glass carbon electrode to enhance the catalytic current of the oxygen reduction reaction. The oleosin antibody was then directed and immobilized onto the surface of the electrode, which had been modified with streptavidin (SPA), through the fragment crystallizable (Fc) region of the antibody. Under optimized conditions, the immunosensor exhibited a linear response within a detection range of 50 to 800 ng/L, with detection limits of 0.616 ng/L for Ses i 4 and 0.307 ng/L for Ses i 5, respectively. The immunosensor demonstrated excellent selectivity and stability, making it suitable for the quantification of sesame oleosins. The comparative analysis of various detection methods for sesame allergens was conducted, revealing that the immunosensor achieved a wide detection range and low limit of detection (LOD). Compared to traditional enzyme-linked immunosorbent assay (ELISA), the immunosensor successfully quantified the allergenicity potential of Ses i 4 and Ses i 5 in roasted sesame seeds at temperatures of 120 °C, 150 °C, and 180 °C. This innovative method offers a new perspective for the rapid quantification of sesame oleosins in foods and real-time monitoring of allergic potential, providing significant advancements in the field of food allergy detection. Full article
(This article belongs to the Special Issue Food Allergen Detection, Identification and Risk Assessment)
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11 pages, 1982 KiB  
Article
Tailoring UV Penetration Depth in Photopolymer Nanocomposites: Advancing SLA 3D Printing Performance with Nanofillers
by Khalid Haj Ahmad, Zurina Mohamad, Zahid Iqbal Khan and Muddasar Habib
Polymers 2025, 17(1), 97; https://doi.org/10.3390/polym17010097 - 1 Jan 2025
Viewed by 408
Abstract
This study examines the influence of nanofillers on the ultraviolet (UV) penetration depth of photopolymer resins used in stereolithography (SLA) 3D printing, and their impact on printability. Three nanofillers, multiwalled carbon nanotubes (MWCNT), graphene nanoplatelets (xGNP), and boron nitride nanoparticles (BNNP), were incorporated [...] Read more.
This study examines the influence of nanofillers on the ultraviolet (UV) penetration depth of photopolymer resins used in stereolithography (SLA) 3D printing, and their impact on printability. Three nanofillers, multiwalled carbon nanotubes (MWCNT), graphene nanoplatelets (xGNP), and boron nitride nanoparticles (BNNP), were incorporated into a commercially available photopolymer resin to prepare nanocomposite formulations. The UV penetration depth (Dp) was assessed using the Windowpane method, revealing a significant reduction with the addition of nanofillers. At a concentration of 0.25 wt.%, MWCNT showed the highest reduction in Dp (90%), followed by xGNP (65%) and BNNP (33%). SLA 3D printing was performed at varying nanofiller concentrations to evaluate printability. The findings highlight a strong correlation between Dp and the maximum printable nanofiller concentration, with MWCNT limiting printability to 0.05 wt.% due to its low Dp, while BNNP allowed printing up to 1.5 wt.%. Mechanical testing showed substantial improvements in hardness and elastic modulus, even at low nanofiller concentrations, with BNNP outperforming other fillers. Compared to a clear photopolymer, the elastic modulus for 3D printed nanocomposite samples with 0.05 wt.% nanofiller compositions showed an improvement of 43% for MWCNT, 63% for xGNP, and 104% for BNNP. The hardness results showed an improvement of 86% for MWCNT, 103% for xGNP, and 179% for BNNP. These results underscore the importance of Dp in determining the layer thickness and print success in SLA 3D printing. Practical applications include the design of advanced photopolymer nanocomposites for biomedical devices, electronics, and lightweight structural components. This research provides valuable insights for tailoring material properties to meet the demands of high-performance additive manufacturing. Full article
(This article belongs to the Special Issue Progress in 3D Printing II)
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15 pages, 6467 KiB  
Article
A Long-Term Stability Study of Co-Pc-Modified Nanosilver for Anion Exchange Membrane Fuel Cells
by Fa-Cheng Su, Yu-Hsiu Lu, Paweena Prapainainar and Hsiharng Yang
Catalysts 2025, 15(1), 25; https://doi.org/10.3390/catal15010025 - 30 Dec 2024
Viewed by 420
Abstract
This study investigated the modification of nanosilver (Ag) by Co-Pc (phthal–cyanine) and the synergistic effect of Ag-Co/CNT (carbon nanotube) for the long-term stability of AEMFCs (anion exchange membrane fuel cells). This study also aimed to use non-precious metal catalysts on both the cathode [...] Read more.
This study investigated the modification of nanosilver (Ag) by Co-Pc (phthal–cyanine) and the synergistic effect of Ag-Co/CNT (carbon nanotube) for the long-term stability of AEMFCs (anion exchange membrane fuel cells). This study also aimed to use non-precious metal catalysts on both the cathode and anode to reduce the catalyst costs. Through a simple and efficient chemical synthesis method, a composite catalyst consisting of Co-Pc-modified Ag/CNT was successfully prepared and characterized for its structure and composition. Co-Pc and Ag were chosen for their high durability and catalytic activity in fuel cells, combined with a multi-wall carbon nanotube (MWCNT) as a carrier for the cathode catalyst, and the anode catalyst used Pd-CeO2/C. The performance of the cell module was tested based on a commercial anion exchange membrane (X37-50RT). The experiment focused on different synthesis times and ratios of catalyst and ionomer, observing the enhancement in Co on the active sites of Ag/CNT. Finally, the cell performance was tested for the optimal loading amount. It was observed that when the loading of the nanosilver–cobalt/carbon nanotube (Ag-Co/CNT) is 1 mg/cm2, the highest power density is 434.1 mW/cm2. Through 100 cycles of testing, only an 18% decrease was observed, while the decrease in open circuit voltage was approximately 4.6%. Compared to nanosilver (Ag/CNT), the Co-Pc-modified nano-Ag with the degradation rate has significantly slowed down, and its catalytic activity has also improved significantly. The enhanced stability of this synergistic effect is mainly attributed to the introduction of cobalt metal, which prevents excessive fusion of nano-Ag particles and surface oxidation, effectively maintaining durability in catalytic activity. Full article
(This article belongs to the Section Electrocatalysis)
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12 pages, 3209 KiB  
Article
Preparation of Molecularly Imprinted Electrochemical Sensors and Analysis of the Doping of Epinephrine in Equine Blood
by Zhao Wang, Yanqi Li, Xiaoxue Xi, Qichao Zou and Yuexing Zhang
Sensors 2025, 25(1), 70; https://doi.org/10.3390/s25010070 - 26 Dec 2024
Viewed by 285
Abstract
In this paper, a novel molecularly imprinted polymer membrane modified glassy carbon electrode for electrochemical sensors (MIP-OH-MWCNTs-GCE) for epinephrine (EP) was successfully prepared by a gel-sol method using an optimized functional monomer oligosilsesquioxane-Al2O3 sol-ITO composite sol (ITO-POSS-Al2O3 [...] Read more.
In this paper, a novel molecularly imprinted polymer membrane modified glassy carbon electrode for electrochemical sensors (MIP-OH-MWCNTs-GCE) for epinephrine (EP) was successfully prepared by a gel-sol method using an optimized functional monomer oligosilsesquioxane-Al2O3 sol-ITO composite sol (ITO-POSS-Al2O3). Hydroxylated multi-walled carbon nanotubes (OH-MWCNTs) were introduced during the modification of the electrodes, and the electrochemical behavior of EP on the molecularly imprinted electrochemical sensors was probed by the differential pulse velocity (DPV) method. The experimental conditions were optimized. Under the optimized conditions, the response peak current values showed a good linear relationship with the epinephrine concentration in the range of 0.0014–2.12 μM, and the detection limit was 4.656 × 10−11 M. The prepared molecularly imprinted electrochemical sensor was successfully applied to the detection of actual samples of horse serum with recoveries of 94.97–101.36% (RSD), which indicated that the constructed molecularly imprinted membrane electrochemical sensor has a high detection accuracy for epinephrine in horse blood, and that it has a better value for practical application. Full article
(This article belongs to the Special Issue Sensing in Supramolecular Chemistry)
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12 pages, 3507 KiB  
Article
Ultrathin MWCNT/Ti3C2Tx Hybrid Films for Electromagnetic Interference Shielding
by Chuanxin Weng, Junzhe He, Jiangxiao Tian, Wei Wu, Jinjin Li, Jiulin Zhang, Haitao Yu, Xuechuan Zhang and Mingming Lu
Nanomaterials 2025, 15(1), 6; https://doi.org/10.3390/nano15010006 - 25 Dec 2024
Viewed by 249
Abstract
The disordered assembly and low conductivity of carbon nanotubes are the main problems that limit the application of electromagnetic interference (EMI) shielding. In this work, an ordered lamellar assembly structure of multiwalled carbon nanotube/Ti3C2Tx (MWCNT/Ti3C2 [...] Read more.
The disordered assembly and low conductivity of carbon nanotubes are the main problems that limit the application of electromagnetic interference (EMI) shielding. In this work, an ordered lamellar assembly structure of multiwalled carbon nanotube/Ti3C2Tx (MWCNT/Ti3C2Tx) hybrid films was achieved by vacuum-assisted filtration through the hybridization of Ti3C2Tx nanosheets and carbon nanotubes, where carbon nanotubes were tightly sticking on the surface of Ti3C2Tx nanosheets via physical adsorption and hydrogen bonding. Compared with the pure carbon nanotubes films, the hybrid MWCNT/Ti3C2Tx films achieved a significant improvement in conductivity of 452.5 S/cm and EMI shielding effectiveness (SE) of 44.3 dB under 50 wt% Ti3C2Tx with a low thickness (8.6 μm) and orderly lamellar stacking structure, which finally resulted in high specific SE (SSE/t, SE divided by the density and thickness) of 55,603.1 dB∙cm2∙g−1. Full article
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20 pages, 12409 KiB  
Article
Improving the Impact Resistance and Post-Impact Tensile Fatigue Damage Tolerance of Carbon Fiber Reinforced Epoxy Composites by Embedding the Carbon Nanoparticles in Matrix
by Yi-Ming Jen, Yu-Jen Chen and Tzung-Han Yu
Polymers 2024, 16(24), 3589; https://doi.org/10.3390/polym16243589 - 22 Dec 2024
Viewed by 420
Abstract
The effect of dispersing multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) in the matrix on the low-velocity impact resistance and post-impact residual tensile strength of the carbon fiber reinforced epoxy composite laminates has been experimentally analyzed in this study. The composite specimens [...] Read more.
The effect of dispersing multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) in the matrix on the low-velocity impact resistance and post-impact residual tensile strength of the carbon fiber reinforced epoxy composite laminates has been experimentally analyzed in this study. The composite specimens with the matrix reinforced by different nanoparticle types and various nanoparticle concentrations (0.1, 0.3, and 0.5 wt.%) were prepared and impacted. The post-impact tensile quasi-static and fatigue tests were performed on the specimens with different configurations to study the influence of aforementioned factors on the impact resistance and damage tolerance. Experimental results show that adding nanoparticles in the matrix increases the maximum impact force, reduces the damage area, and alleviates the dent depth of the laminates remarkedly. Moreover, the improvement in these impact resistances increases with the applied nanoparticle concentrations. The nano-modified composite laminates present higher post-impact static strength and longer fatigue life than the specimens with a neat epoxy matrix. Furthermore, both the post-impact static tensile strength and fatigue life increase with the applied nanoparticle concentrations. The damage areas measured using infrared thermography were found to increase linearly with the applied fatigue cycles for all the studied specimens with various configurations. The damage area growth rates of nano-modified composite laminates decrease significantly as the applied nanoparticle concentrations increase. The MWCNTs present better performance than GNPs in improving post-impact static strength and extending the residual fatigue life, however the effect of applied nanoparticle type on the fatigue damage growth rate is slight. Full article
(This article belongs to the Special Issue Fiber Reinforced Polymers: Manufacture, Properties and Applications)
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16 pages, 2846 KiB  
Article
Development of Single-Walled Carbon Nanotube-Based Electrodes with Enhanced Dispersion and Electrochemical Properties for Blood Glucose Monitoring
by Dong-Sup Kim, Abdus Sobhan, Jun-Hyun Oh, Jahyun Lee, Chulhwan Park and Jinyoung Lee
Biosensors 2024, 14(12), 630; https://doi.org/10.3390/bios14120630 - 19 Dec 2024
Viewed by 491
Abstract
The evolution of high-performance electrode materials has significantly impacted the development of real-time monitoring biosensors, emphasizing the need for compatibility with biomaterials and robust electrochemical properties. This work focuses on creating electrode materials utilizing single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), [...] Read more.
The evolution of high-performance electrode materials has significantly impacted the development of real-time monitoring biosensors, emphasizing the need for compatibility with biomaterials and robust electrochemical properties. This work focuses on creating electrode materials utilizing single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), specifically examining their dispersion behavior and electrochemical characteristics. By using ultrasonic waves, we analyzed the dispersion of CNTs in various solvents, including N, N-dimethylformamide (DMF), deionized water (DW), ethanol, and acetone. The findings revealed that SWCNTs achieved optimal dispersion without precipitation in DMF. Additionally, we observed that the electrical resistance decreased as the concentration of SWCNTs increased from 0.025 to 0.4 g/L, with significant conductivity enhancements noted between 0.2 g/L and 0.4 g/L in DMF. In constructing the biosensor platform, we employed 1-pyrenebutanoic acid succinimidyl ester (PBSE) as a linker molecule, while glucose oxidase (Gox) served as the binding substrate. The interaction between Gox and glucose led to a notable decrease in the biosensor’s resistance values as glucose concentrations ranged from 0.001 to 0.1 M. These results provide foundational insights into the development of SWCNT-based electrode materials and suggest a promising pathway toward the next generation of efficient and reliable biosensors. Full article
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8 pages, 1950 KiB  
Communication
Creation of Flexible Heterogeneously-Doped Carbon Nanotube Paper PN Diodes to Enhance Thermoelectric and Photovoltaic Effects
by Jih-Hsin Liu and Chen-Yu Yen
Processes 2024, 12(12), 2898; https://doi.org/10.3390/pr12122898 - 18 Dec 2024
Viewed by 394
Abstract
This study investigates the fabrication and characterization of flexible PN diode devices using phosphorus- and boron-doped carbon nanotube (CNT) paper, also known as Buckypaper (BP). The BP substrate is fabricated from multi-walled carbon nanotubes (MWCNTs) and doped with phosphorus and boron to form [...] Read more.
This study investigates the fabrication and characterization of flexible PN diode devices using phosphorus- and boron-doped carbon nanotube (CNT) paper, also known as Buckypaper (BP). The BP substrate is fabricated from multi-walled carbon nanotubes (MWCNTs) and doped with phosphorus and boron to form N-type and P-type semiconductors, respectively. Various experimental techniques, including Raman spectroscopy, Hall effect measurements, and scanning electron microscopy (SEM), are employed to analyze the properties of the doped BP. The results reveal that the current-voltage (I-V) and capacitance-voltage (C-V) characteristics preliminarily exhibit the basic electrical properties of a diode after doping with P-type and N-type carriers. Subsequently, optimized vertical stacking combined with parallel electrode configurations for the BP diode devices demonstrates that vertical series stacking gradually enhances the thermoelectric voltage, while horizontal parallel connections approximately scale up the thermoelectric and photovoltaic voltages proportionally. The findings underscore the critical role of creating heterogeneously doped CNT-paper PN junction electric fields in improving the performance of carbon-based semiconductor devices. Furthermore, we demonstrate that these directionally oriented energy devices, when stacked, can form modular systems with enhanced efficiency. This work highlights the potential of flexible carbon material-based devices for advanced thermoelectric and photovoltaic applications. Full article
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16 pages, 4552 KiB  
Article
Effective Multi-Layered Structure Design with Carbon-Based Hybrid Polymer Nanocomposites Using Evolutionary Algorithms
by Javed Syed
J. Compos. Sci. 2024, 8(12), 537; https://doi.org/10.3390/jcs8120537 - 17 Dec 2024
Viewed by 401
Abstract
Electromagnetic wave-absorbing materials (EMAMs) and structures are crucial in aerospace and electronic communications due to their ability to absorb electromagnetic waves. The development of materials that are lightweight, sustainable, and cost-effective, exhibiting high-performance absorption across a broad frequency spectrum, is therefore important. However, [...] Read more.
Electromagnetic wave-absorbing materials (EMAMs) and structures are crucial in aerospace and electronic communications due to their ability to absorb electromagnetic waves. The development of materials that are lightweight, sustainable, and cost-effective, exhibiting high-performance absorption across a broad frequency spectrum, is therefore important. However, homogeneous electromagnetic absorbing materials require assistance to meet all these criteria. Therefore, developing multi-layer absorbing coatings is essential for enhancing performance. The present study uses 21 different composites of varying weight fractions of polypropylene, graphene nanoplatelets, and multiwall carbon nanotubes nanocomposites to develop multi-layer absorbing materials and optimize their performance. These multi-layer carbon polymer nanocomposites were meticulously constructed using evolutionary algorithms like Non-sorted Genetic Algorithm-II and Particle Swarm Optimization to achieve ultra-broadband electromagnetic wave absorption capabilities. Among the designed electromagnetic absorbing materials, a two-layer model, i.e., 1.5 wt% MWCNT/PP/epoxy with a thickness of 1.052 mm and 2.7% GNP/PP/epoxy with a thickness of 4.456 mm totaling 5.506 mm, was identified as optimal using NSGA-II. The structure has exhibited exceptional absorption performance with a minimum reflection loss of −21 dB and a qualified bandwidth extending to 4.2 GHz. PSO validated and optimized this structure, confirming NSGA-II’s efficiency and effectiveness in quickly obtaining optimal solutions. This broadband absorber design combines the structure design and material functioning through additive manufacturing, allowing it to absorb well over a wide frequency range. Full article
(This article belongs to the Section Nanocomposites)
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19 pages, 6000 KiB  
Article
Comparison of Single and Multiple Intratracheal Administrations for Pulmonary Toxic Responses of Multi-Walled Carbon Nanotubes in Rats
by Hideki Senoh, Masaaki Suzuki, Hirokazu Kano, Tatsuya Kasai and Shoji Fukushima
Nanomaterials 2024, 14(24), 2019; https://doi.org/10.3390/nano14242019 - 16 Dec 2024
Viewed by 493
Abstract
The purpose of the present study is to contribute to the establishment of a standard method for evaluating the adverse effects of nanomaterials by intratracheal administration. Low and high doses of multi-walled carbon nanotubes (MWCNTs) were administered to rats in a single administration [...] Read more.
The purpose of the present study is to contribute to the establishment of a standard method for evaluating the adverse effects of nanomaterials by intratracheal administration. Low and high doses of multi-walled carbon nanotubes (MWCNTs) were administered to rats in a single administration or the same final dose as the single administration but divided over four administrations. Bronchoalveolar lavage examination on day 14 showed an inflammatory reaction and cytotoxicity in the lung, generally greater at the higher dose, and tending to be greater in the rats with four administrations at both the low and high doses. Histopathologic findings showed increased alveolar macrophages and MWCNT deposition (fibers phagocytosed by alveolar macrophages and fibers that were not phagocytosed) in the alveolar space, granulomatous changes, and MWCNT deposition in bronchus-associated lymphoid tissue (BALT) and lung-related lymph nodes on days 14, 28, and 91. In addition, alveolar type II epithelial hyperplasia was observed on day 91, and fibrosis of the alveolar wall was observed on days 28 and 91. Fewer alveolar macrophages with phagocytosed MWCNTs were present at day 91 compared to day 28. MWCNT deposition tended to be higher in the BALT after a single administration, whereas deposition was higher in the lung-related lymph nodes after four administrations. MWCNTs were considered to be transported from the lungs or BALT to the lymph nodes over time. There were no significant differences in MWCNT deposition in the lung after the single administration compared with four administrations at either the low or high doses, and the histopathological findings were similar after single and four administrations, at both the low and high doses. Based on the above findings, a toxicity evaluation of the nanomaterials can be sufficiently performed by intratracheal administration, even with a single intratracheal administration. Full article
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