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Development of enhanced multiwalled carbon nanotube (MWCNT) conductive polymeric nanocomposites by using acidified derivative of MWCNT as dispersant
摘要： The agglomeration of pristine multiwalled carbon nanotubes (MWCNTs) within a polymer matrix has largely limited the efficient conductive reinforcement of MWCNTs-based polymeric nanocomposites. In this paper, the pristine MWCNTs realized well-dispersed with the assistance of nitric acid acidified MWCNTs. The as-prepared hybrid MWCNTs were used to prepare hybrid MWCNTs buckypaper and hybrid MWCNTs/polyvinyl butyral (PVB) nanocomposites. The hybrid MWCNTs dispersion maintained good dispersing stability over 3 months. The fabrication of hybrid MWCNTs buckypaper shows that the intrinsic conductivity of the hybrid MWCNTs is 25.1 ± 0.2 S/cm, higher than the pristine ones of 23.3 ± 0.2 S/cm. The SEM images of hybrid MWCNTs/PVB nanocomposites show that hybrid MWCNTs are distributed homogenously in the PVB matrix. The conductive performance of nanocomposites is significantly enhanced with a low percolation of 0.44 ± 0.05 wt. % and a high critical exponent of 3.57.
关键词： MWCNTs,conductive reinforcement,multiwalled carbon nanotubes,dispersant,polymeric nanocomposites
更新于2025-09-23 15:19:57
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Preparation method and underlying mechanism of MWCNTs/Ti6Al4V nanocomposite powder for selective laser melting additive manufacturing
摘要： The fabrication of high-performance metal matrix nanocomposites is a new development direction in laser additive manufacturing (AM); however, the unique localized line-by-line and layer-by-layer forming process of AM has special requirements on the applicable powder materials for AM. The feedstock powder preparation is an important factor in laser AM, especially the CNTs/metal nanocomposite powder for selective laser melting (SLM) due to the agglomeration of the CNTs. This work focused on the preparation of multi-walled carbon nanotubes/Ti6Al4V (MWCNTs/TC4) nanocomposite powder for laser AM by a planetary ball-milling (PBM). The effect of ball-milling time on the characteristics of nanocomposite powder was studied and the underlying physical mechanism for powder preparation was disclosed. Three nanocomposite powders with milling time of 2 h, 4 h and 16 h were used for SLM processing to determine the optimal nanocomposite powders. The results showed that although the MWCNTs were dispersed uniformly in the matrix powder at increased milling time, severely plastic deformation of nanocomposite powder occurred with loss of its spherical shape. It was concluded that a ball-milling time of 4 h at a speed of 300 rpm was determined to achieve optimal nanocomposite powder for SLM. SLM processing of the nanocomposite powder demonstrated a smooth laser-powder interaction, yielding good metallurgical bonding of scanning tracks with previous tracks and relatively flat surface of samples. This work provided the significant reference to prepare high quality CNTs/metal nanocomposite powder for SLM, which has great potentials to fabricate high-performance metal matrix nanocomposite.
关键词： Planetary ball milling,Selective laser melting,Ti6Al4V (TC4) powder,Multi-walled carbon nanotubes (MWCNTs),Powder characteristics
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Optical Fiber Probe for the Selective Plasmonic Sensing of Catechol Utilizing ZnO Decorated MWCNTs
摘要： The widespread use of dihydroxybenzenes in various industries like photography, pesticides, dyes, antioxidants and medicines has lead their inadvertent disposal in soil and water. Catechol is an isomer of dihydroxybenzene whose disposal in ground and river water has necessitated requirement of its highly sensitive sensor due to its toxic effects. Being of polar nature it is easily uptaken by cells but not released properly leading to its accumulation in cells. It is regarded as human group 2B carcinogen by IARC with severe effect on central nervous system. Due to its toxicity, co-carcinogenic activity and low biodegradability it is declared as serious threat for ecology by USEPA and Europian Union [1, 2]. Therefore, we report, here, a selective and sensitive surface plasmon resonance (SPR) based catechol sensor utilising zinc oxide decorated multi-walled carbon nanotubes (MWCNTs) functionalised with CTAB (cetyl trimethyl ammonium bromide) as a sensing layer on an optical fiber probe. Surface plasmon technique makes the sensor highly sensitive, whereas use of an optical fiber provides the advantage of miniaturised probe with facility of continuous online monitoring. The sensor fabrication broadly consists of three steps. The first step involves the chemical route for the preparation of nanocomposite. Firstly, ZnO nanoparticles were prepared through the reduction of zinc acetate by NaOH. Then the nanoparticles were decorated on sidewall functionalised MWCNTs followed by functionalization with CTAB [3]. The TEM image of ZnO decorated MWCNTs is shown in fig.1(a). The second step involves the thermal deposition of silver on 1 cm uncladded region of the fiber probe. Finally, the nanocomposite was coated on the fiber probe by dip coating method. All the steps of probe fabrication are schematically depicted in fig.1(b). To characterize, the probe was fixed in a flow cell having the facility of inlet and outlet for the samples. Polychromatic light was launched from one end of the probe and the SPR spectrum of the catechol sample of a given concentration in the flow cell was recorded by the spectrometer at the other end.
关键词： surface plasmon resonance,optical fiber probe,CTAB,catechol,ZnO decorated MWCNTs
更新于2025-09-16 10:30:52
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Paper-Based Flexible Electrode Using Chemically-Modified Graphene and Functionalized Multiwalled Carbon Nanotube Composites for Electrophysiological Signal Sensing
摘要： Flexible paper-based physiological sensor electrodes were developed using chemically-modified graphene (CG) and carboxylic-functionalized multiwalled carbon nanotube composites (f@MWCNTs). A solvothermal process with additional treatment was conducted to synthesize CG and f@MWCNTs to make CG-f@MWCNT composites. The composite was sonicated in an appropriate solvent to make a uniform suspension, and then it was drop cast on a nylon membrane in a vacuum filter. A number of batches (0%~35% f@MWCNTs) were prepared to investigate the performance of the physical characteristics. The 25% f@MWCNT-loaded composite showed the best adhesion on the paper substrate. The surface topography and chemical bonding of the proposed CG-f@MWCNT electrodes were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The average sheet resistance of the 25% CG-f@MWCNT electrode was determined to be 75 ?/(cid:3), and it showed a skin contact impedance of 45.12 k? at 100 Hz. Electrocardiogram (ECG) signals were recorded from the chest and fingertips of healthy adults using the proposed electrodes. The CG-f@MWCNT electrodes demonstrated comfortability and a high sensitivity for electrocardiogram signal detection.
关键词： solvothermal-treated,flexible dry electrode,graphene-based composites,electrocardiogram,functionalized MWCNTs
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE SENSORS - Montreal, QC, Canada (2019.10.27-2019.10.30)] 2019 IEEE SENSORS - Crumpled Carbon Nanotube Thin Film Heaters for High Sensitivity Hydrogen Sensing
摘要： This paper reports the fabrication and characterization of crumpled multi-walled carbon nanotube (CNT) thin film heater and its application towards hydrogen gas sensing. We have fabricated MWCNTs thin film heater by a simple spray coating and thermally shrinking the polystyrene (PS) substrate. Thermal shrinkage results crumpled CNTs with closely packed junctions, leading to a higher heating temperature at a given input voltage. Such efficient heating capabilities of the crumpled CNT heater are favorable for hydrogen gas sensing with good desorption characteristics. Our results show that higher operating temperatures result in better measurement sensitivities. In addition, the heating performance and temperature coefficient of resistance (TCR) of CNT heaters are analyzed for an accurate temperature control. The suggested crumpled CNT heaters can be applied for low-voltage gas sensing platforms.
关键词： gas sensor,Hydrogen sensing,MWCNTs,Thin film heater,Joule heating,Substrate shrinkage
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES19Gr - Athens, Greece (4–6 September 2019)] TECHNOLOGIES AND MATERIALS FOR RENEWABLE ENERGY, ENVIRONMENT AND SUSTAINABILITY: TMREES19Gr - I-V characteristics of n-Si /ZnO/Se/MWCNTs nanocomposite solar cell fabricated by solvothermal technique
摘要： I-V Characteristics of n-Si/ZnO/Se/MWCNTs nanocomposite solar cell fabricated by solvothermal technique were investigated, deals with the fabrication of heterojunction solar cell was by deposited ZnO-Se-MWCNTs nanocomposite on the n-Si substrate using Pulsed Laser Deposition technique. FE-SEM images show that the diameters of the prepared MWCNTs is up to several micrometers in length and also some of ZnO and Se NPs were closely linked to the surface of MWCNTs. So, the diameter of the coated MWCNTs was increased as a result. XRD shows that the prepared ZnO-Se-MWCNTs nanocomposite has a homogeneous structure with average crystallite sizes (30.86-56) nm. UV-Vis. Spectra show enhancement of absorption for ZnO-Se-MWCNTs nanocomposite material in comparison with MWCNTs. The characteristics of current-voltage heterojunction showed that the forward bias current change nearly exponentially with the applied voltage in dark and this is consistent with tunneling –recombination model. The fill factor of the fabricated n-Si/ZnO/Se/MWCNTs nanocomposite solar cell was 50 %, while the efficiency η was 7 under illumination.
关键词： solar cell,hybrid materials,MWCNTs
更新于2025-09-16 10:30:52
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Synthesis of MoS2–MoO2/MWCNTs counter electrode for high-efficient dye-sensitized solar cells
摘要： In this work, MoS2–MoO2 and MoS2–MoO2/MWCNTs counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) were prepared by sulfurization of a one-pot hydrothermally obtained MoO2 film and MoO2/MWCNTs composite film on fluorine-doped tin oxide glasses at 500?°C for 2?h in argon atmosphere. The promoted MoS2 particles on a surface of MoS2–MoO2 and MoS2–MoO2/MWCNTs films were identified by X-ray diffraction to have a hexagonal structure. Morphology of MoO2, MoO2/MWCNTs, MoS2–MoO2, and MoS2–MoO2/MWCNTs CEs was studied using field emission scanning electron microscope and transmission electron microscope. Functional groups in MoS2–MoO2/MWCNTs sample were identified by Raman spectroscopy. Results of cyclic voltammetry and electrochemical impedance spectroscopy displayed a high electrocatalytic activity performance and low charge transfer resistance of MoS2–MoO2/MWCNTs CE as compared to those of MoO2, MoO2/MWCNTs, and MoS2–MoO2 CEs. Interestingly, the DSSC based on MoS2–MoO2/MWCNTs CE could provide the higher power conversion efficiency of 7.79% compared to that of 7.26% for Pt-based DSSC.
关键词： electrocatalytic activity,dye-sensitized solar cells,counter electrode,MoS2–MoO2,MWCNTs
更新于2025-09-12 10:27:22
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Q-switching Zirconia-Erbium-doped Pulsed Fiber Laser with MWCNTs-PEO as Saturable Absorber
摘要： Q-switched pulses provide a significant contribution to recent biomedical applications such as laser treatment, medical imaging, biomedical diagnoses and spectroscopy due to high efficiency, compact device, less footprint, flexibility and cost effective. A successful generation of Q-switching pulsed fiber laser by using a homemade fiber of zirconia-based erbium-doped fiber (Zr-EDF) with the utilization multi-walled carbon nanotubes-polyethylene oxide (MWCNTs-PEO) as saturable absorber is reported. The active medium is 1 meter length of Zr-EDF with -0.6 ps2 group delay dispersion (GDD) for overall setup arrangement. At maximum pump power 126 mW, the repetition rate, pulse duration, output power and pulse energy are 17.3 kHz, 7.57 μs, 1.13 mW and 65.03 nJ, respectively.
关键词： MWCNTs-PEO,Saturable Absorber,Pulsed Fiber Laser,Q-switching,Zirconia-Erbium-doped fiber
更新于2025-09-12 10:27:22
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Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation
摘要： Aromatic volatile organic compound (VOC) sensors are attracting growing interest as a response to the pressing market need for sensitive, fast response, low power consumption and stable sensors. Benzene and toluene detection is subject to several potential applications such as air monitoring in chemical industries or even biosensing of human breath. In this work, we report the fabrication of a room temperature toluene and benzene sensor based on multiwall carbon nanotubes (MWCNTs) decorated with gold nanoparticles and functionalised with a long-chain thiol self-assembled monolayer, 1-hexadecanethiol (HDT). High-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR) were performed to characterize the gold nanoparticle decoration and to examine the thiol monolayer bonding to the MWCNTs. The detection of aromatic vapours using Au-MWCNT and HDT/Au-MWCNT sensors down to the ppm range shows that the presence of the self-assembled layer increases the sensitivity (up to 17 times), selectivity and improves the response dynamics of the sensors.
关键词： multiwall carbon nanotubes (MWCNTs),vapour sensor,sensitivity,gold-decorated MWCNTs,self-assembled monolayers (SAMs),selectivity
更新于2025-09-11 14:15:04
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Facile preparation and properties of polyvinylidene fluoride dielectric nanocomposites <i>via</i> phase morphology control and incorporation of multiwalled carbon nanotubes conductive fillers
摘要： A novel PVDF dielectric nanocomposite was achieved by controlling phase morphology and incorporating conductive ?llers simultaneously, and the mechanical, thermal, dielectric properties of the resultant dielectric nanocomposites were investigated. Mechanical analysis showed that incorporation of modi?ed MWCNTs (MWCNTs-COOH) in the PVDF nanocomposites resulted in signi?cant improvements on the tensile strength (Ts) and elasticity modulus (Em). When the ?ller content was 12 wt%, the Ts of MWCNTs-COOH/PVDF could reach 64.6 MPa. XRD test showed that the addition of MWCNTs-COOH and MWCNTs promoted the formation of β-phase of PVDF. DMA analysis showed that the glass-transition temperature of the PVDF nanocomposites slightly increases on loading of original MWCNTs and this effect was more pronounced on loading MWCNTs-COOH. The dielectric property analysis showed that the original MWCNTs were more likely to form local conductive networks in the PVDF matrix, promoting the electron displacement polarization, and improving the dielectric constant. When the contents of MWCNTs was 12 wt%, the percolation threshold was obtained and the dielectric constant (ε0) reached 286, which was 36 times of pure PVDF. Our work provides a simple way to fabricate polymer blends with excellent dielectric performances, good mechanical properties as well as good processing capability but low cost.
关键词： polyvinylidene ?uoride (PVDF),thermal performance,dielectric properties,multi-walled carbon nanotubes (MWCNTs),mechanical properties
更新于2025-09-11 14:15:04