MWCNT Network Research Articles

Artificial Neural Networks With Fast Transfer Learning for Statistical Signal Integrity Analysis of MWCNT and MLGNR Interconnect Networks

Artificial Neural Networks With Fast Transfer Learning for Statistical Signal Integrity Analysis of MWCNT and MLGNR Interconnect Networks

Synthesis and enhanced room-temperature thermoelectric properties of CuO-MWCNT hybrid nanostructured composites.

This work presents the synthesis of novel copper oxide-multiwalled carbon nanotube (CuO-MWCNT) hybrid nanostructured composites and a systematic study of their thermoelectric performance at near-room temperatures as a function of MWCNT wt% in the composite. The CuO-MWCNT hybrid nanostructured composites were synthesized by thermal oxidation of a thin metallic Cu layer pre-deposited on the MWCNT network. This resulted in the complete incorporation of MWCNTs in the nanostructured CuO matrix. The thermoelectric properties of the fabricated CuO-MWCNT composites were compared with the properties of CuO-MWCNT networks prepared by mechanical mixing and with the properties of previously reported thermoelectric [CuO]99.9[SWCNT]0.1 composites. CuO-MWCNT hybrid composites containing MWCNTs below 5 wt% showed an increase in the room-temperature thermoelectric power factor (PF) by ∼2 times compared with a bare CuO nanostructured reference thin film, by 5-50 times compared to mixed CuO-MWCNT networks, and by ∼10 times the PF of [CuO]99.9[SWCNT]0.1. The improvement of the PF was attributed to the changes in charge carrier concentration and mobility due to the processes occurring at the large-area CuO-MWCNT interfaces. The Seebeck coefficient and PF reached by the CuO-MWCNT hybrid nanostructured composites were 688 μV K-1 and ∼4 μW m-1 K-2, which exceeded the recently reported values for similar composites based on MWCNTs and the best near-room temperature inorganic thermoelectric materials such as bismuth and antimony chalcogenides and highlighted the potential of CuO-MWCNT hybrid nanostructured composites for applications related to low-grade waste heat harvesting and conversion to useable electricity.

The Impact of Topological States on the Thermoelectric Performance of p- and n-Type Sb2Te3/Bi2Se3-Multiwalled Carbon Nanotubes Heterostructured Networks

The resistance and magnetoresistance of flexible thermoelectric p-type Sb2Te3-MWCNT, p-type Bi2Se3-MWCNT, and n-type Bi2Se3-MWCNT heterostructures were studied in the temperature range from 2 K to 300 K to reveal the conductance mechanisms governing the thermoelectric properties of these heterostructured networks. It was found that the conductance in heterostructured networks at different temperatures is governed by different processes and components of the networks. This effect was found to be related to the growth mechanisms of the Sb2Te3 and Bi2Se3 nanostructures on the MWCNT networks. At near-room temperatures, the Sb2Te3 and Bi2Se3 nanostructures were found to have the dominant contribution to the total conductance of the p-type Sb2Te3-MWCNT and n-type Bi2Se3-MWCNT networks. In turn, the conduction of p-type Bi2Se3-MWCNT heterostructured networks in a full temperature range and p-type Sb2Te3-MWCNT and n-type Bi2Se3-MWCNT heterostructured networks at temperatures below 30 K was governed by the MWCNTs; however, with the contribution from 2D topological states of Sb2Te3 and Bi2Se3 nanostructures, these were manifested by the weak antilocalization effect (WAL) cusps observed at temperatures below 5–10 K for all heterostructured networks considered in this work.

Fabrication of multiwalled carbon nanotubes/MoS2 nanocomposite: Application as temperature sensor

In this work, the fabrication of a multiwalled carbon nanotube/molybdenum disulfide (MWCNT@MoS2) composite thin-film-based highly sensitive temperature sensor is reported. The efficiency of the sensor is estimated through its parameters such as temperature coefficient of resistance (TCR), and thermal hysteresis (Hth), which are the key parameters of the efficient thermometer. The sensing parameters like TCR and Hth both regulate heat transport in the thermometer and control the additional sensing properties including response magnitude, response and recovery time, sensitivity, and resolution. MoS2 wrapped on the MWCNT network observes the hopping of electrons and increases the carrier mobility of the MoS2 nanostructure for temperature sensing study. The MWCNT@MoS2 composite sensor tested in the high-temperature range (298–373 K) displays TCR of −0.62%/K, a response time of ∼73 s, a recovery time of ∼89 s, and ∼0.57% hysteresis loss. In the low-temperature range (298–173 K), the TCR increases many folds to ∼2.07%/K with ∼0.39% hysteresis loss. These results are encouraging for the development of low-cost, highly sensitive resistive sensors that may spark interest in solid-state thermometer applications.

Hydrophobic and flame-retardant multifunctional foam for enhanced thermal insulation and broadband microwave absorption via a triple-continuous network of RGO/MWCNT-melamine composite

Multifunctionalization is the future development trend for electromagnetic wave absorption (EMA) materials to satisfy practical scenarios. In this manuscript, a lightweight RGO/MWCNT modified melamine sponge (CGMFs) with a 3D porous triple-continuous network is developed, which exhibit much enhanced microwave absorption performance and multifunctional characteristics. The micro/nano-structure and EMA performance of CGMFs can be effectively controlled by adjusting the concentration and proportion of RGO and MWCNT. It is found that excellent impedance matching property from the 3D porous structure and strong electromagnetic wave (EMW) dissipation property of RGO and MWCNT network can synergistically enhanced the broadband EMA performance. The CGMFs present remarkable effective absorption bandwidth (EAB, reflection loss value ≤ −10 dB) of 10.8 GHz and extremely high reflection loss value of −50.43 dB at a thickness of 4.6 mm. Moreover, the CGMFs exhibit good mechanical stability, which can be compressed, bent, and twisted arbitrarily. Benefiting from enhanced hydrophobicity, heat insulation, and nonflammability, the CGMFs also exbibit attractive functions of self-cleaning, thermal insulation, infrared stealth, and flame retardancy. This study paves the way for scalable fabrication of next-generation multifunctional high-performance broadband EMA materials for practical application.

Ferrocene-Grafted Carbon Nanotubes for Sensitive Non-Enzymatic Electrochemical Detection of Hydrogen Peroxide.

Sensitive detection of hydrogen peroxide (H2O2) residue in aseptic packaging at point of use is critical to food safety. We present a sensitive non-enzymatic, amperometric H2O2 sensor based on ferrocene-functionalized multi-walled carbon nanotubes (MWCNT-FeC) and facile screen-printed carbon electrodes (SPCEs). The sensor utilizes the covalently grafted ferrocene as an effective redox mediator and the MWCNT networks to provide a large active surface area for efficient electrocatalytic reactions. The electrocatalytic MWCNT-FeC modified electrodes feature a high-efficiency electron transfer and a high electrocatalytic activity towards H2O2 reduction at a low potential of -0.15 V vs. Ag/AgCl. The decreased operating potential improves the selectivity by inherently eliminating the cross-reactivity with other electroactive interferents, such as dopamine, glucose, and ascorbic acid. The sensor exhibits a wide linear detection range from 1 μM to 1 mM with a detection limit of 0.49 μM (S/N=3). The covalently functionalized electrodes offered highly reproducible and reliable detection, providing a robust property for continuous, real-time H2O2 monitoring. Furthermore, the proposed sensor was successfully employed to determine H2O2 levels in spiked packaged milk and apple juice with satisfactory recoveries (94.33-97.62%). The MWCNT-FeC modified SPCEs offered a facile, cost-effective method for highly sensitive and selective point-of-use detection of H2O2.

MWCNT incorporated wool-ball-like CuO@NiO hybrid nanostructures for high-performance energy storage device

In the present work, some CuO@NiO@MWCNT (CNC) ternary hybrid nanostructures have been synthesized solvothermally in a well-controlled manner by varying the amount of MWCNT for energy storage application with superior electrochemical performance. Among three CNC1 (CuO@NiO:40 mg MWCNT), CNC2 (CuO@NiO:40 mg MWCNT; in one-step method) and CNC3 (CuO@NiO:60 mg MWCNT) nanocomposites, the CNC1 has emerged out with the best performance due to its well-designed components and synergistic effects, wool ball-like morphology and a mesoporous structure containing more active sites, a shortest conductive pathway for electron-ion transportation. The CNC1 hybrid with a highly ordered mesoporous structure (pore radius ~1.9 nm) offers a high specific surface area of 262 m2 g−1. The structure and microstructure of these ternary hybrid nanocomposites are characterized by analyzing respective X-ray diffraction patterns, HRTEM, FESEM images, and XPS spectra. HRTEM and FESEM images reveal the uniform distribution of the MWCNT network and the growth of spherical NiO nanoparticles of 8–10 nm in these CNT. The optimized ternary wool ball-like CNC1sample exhibits a high specific capacitance of 786 F g−1 and high areal capacitance of 3.144 F cm−2at a current density of 0.6 A g−1 with a significant rate capability. A two-electrode asymmetric device has been designed with the CNC1 sample as the positive electrode and activated carbon as the negative electrode in a 1 M Na2SO4 electrolyte medium. This device offers maximum specific energy of 32.21 Wh Kg−1, a maximum power density of 3923 W Kg−1, excellent cyclic stability and a high Coulomb efficiency. The optimum use of MWCNT in CNC1 ternary nanostructures results in better morphology, leading to a significant reduction in charge transfer parameters,as revealed by EIS spectroscopy.

Modeling the Conductivity Response to NO2 Gas of Films Based on MWCNT Networks.

This work proposes a model describing the dynamic behavior of sensing films based on functionalized MWCNT networks in terms of conductivity when exposed to time-variable concentrations of NO2 and operating with variable working temperatures. To test the proposed model, disordered networks of MWCNTs functionalized with COOH and Au nanoparticles were exploited. The model is derived from theoretical descriptions of the electronic transport in the nanotube network, of the NO2 chemisorption reaction and of the interaction of these two phenomena. The model is numerically implemented and then identified by estimating all the chemical/physical quantities involved and acting as parameters, through a model fitting procedure. Satisfactory results were obtained in the fitting process, and the identified model was used to further the analysis of the MWCNT sensing in dynamical conditions.

Oxidized MWCNTs as an Oxidizing Agent and Dopant in MWCNT@Polypyrrole Composite Formation**

AbstractA new approach to the formation of composites of carbon nanotubes and polypyrrole (PPy) is proposed. Oxidized multi‐walled carbon nanotubes (ox‐MWCNTs) are used as oxidation agents in pyrrole polymerization. The polymeric phase is deposited both at the surface of the carbon nanotube to form a core‐shell structure and in the empty spaces of the MWCNT network. Each form of the polypyrrole phase exhibits different electrochemical properties. PPy deposited directly at the carbon nanotube surface as a uniform and dense layer is oxidized at less positive potentials, compared to the polymeric material deposited in the pores of the nanotube network. MWCNTs with anions incorporated into structural defects formed during their oxidation in a piranha solution also act as dopants of the oxidized form of PPy. The polymeric film deposited directly at the ox‐MWCNT surface is in its oxidized state. The redox processes involving this part of the PPy film are accompanied by the transport of cations of the supporting electrolyte. The charge transfer between ox‐MWCNTs and the deposited PPy film is confirmed by the results of the theoretical calculations of the energy states at the carbon nanotube and polypyrrole interface. A neutral PPy film located in layers remote from the surface of the nanotube is oxidized at more positive potentials. The oxidation of PPy located in the pores of the ox‐MWCNT network results in a broad voltammetric peak formation.

Patternable cellulose/MWCNT laminated nanocomposites with anisotropic thermal and electrical conductivity

To construct eco-friendly materials with anisotropic thermal/electrical conductivity and designable structure and shape not only is the goal of electrical materials, but also meets the requirement of sustainable society. In this work, patternable and laminated cellulose/MWCNT nanocomposites with excellent anisotropic thermal and electrical conductivity are prepared by a scalable and eco-friendly process, including a paper-making step, assembly step and in-situ welding step. In the obtained nanocomposites, the cellulose layer acts as the insulator, and the cellulose/MWCNT layer as the electrical and thermal conductor with a special segregated MWCNT network. As a result, the in-plane and through-plane electrical conductivity of the cellulose/MWCNT nanocomposite with 22.7 wt% MWCNT are 1458 and 1.48 × 10-10 S/m, respectively, and the in-plane and through-plane thermal conductivity are 1.98 and 0.34 W·m-1·K-1, respectively. Moreover, the cellulose/MWCNT nanocomposites have high electromagnetic shielding effectiveness of 31.1 dB when the thickness is 0.9 mm, good tensile strength of 156 MPa, and high shape stability at 240 °C. More interestingly, the laminated cellulose/MWCNT materials with patterned shape and sophisticated conductive circuit can be easily fabricated to work as a special and custom-tailor electronic element, thermal management device and electric-heating anti-counterfeiting pattern. Such novel cellulose/MWCNT nanocomposites prepared by a simple, effective and scalable process exhibit a huge potential in environmentally-friendly electrical and thermal management device, electromagnetic shielding element and advanced electronic anti-counterfeiting tag.

MWCNT enabled smart textiles based flexible and wearable sensor for human motion and humidity monitoring

In the study, we present a simple MWCNT enhanced textile based wearable device which can measure the change in human body motion as well as humidity of the environment for practical applications. Multiwalled carbon nanotube modified textile was fabricated by spray layer by layer method. Morphology, structure, thermal and conductive properties of the MWCNT modified textiles were investigated. The resistance of MWCNT network on textile could be controlled in a wide range from 100 MOhm to 2 KOhm by varying the concentration (1 mg/mL to 5 mg/mL) and a number of spray coating of MWCNT. The fabricated MWCNT enhanced textile sensors were attached to various human body parts (such as forehead, cheek, neck, abdomen, wrist, elbow, knee, wrist) and change in resistance pertaining to human body motion was measured. The wrist movement shows a decrease in the sensor resistance and elbow movement shows an increase in the resistance depends upon forward and reverse (due to compression and expansion of MWCNT junction network) bending of MWCNT coated fabric sensor. Further, the smart fabric was applied to monitor a wide range of humidity (RH = 19–93%) at room temperature. The sensor show high response for relative humidity (RH) of 57% with quick response (4 ± 2 s) and recovery times (14 ± 2 s) at room temperature. The change in resistance of the sensor on exposure to humidity could be attributed to the interaction of water molecules with surface (COOH, and OH) functional groups on MWCNT. The present results could be interesting for the development of simple, large scale and low cost textile based wearable sensors for multifunctional sensing applications.

Conductive Skeleton-Heterostructure Composites Based on Chrome Shavings for Enhanced Electromagnetic Interference Shielding.

Renewable bio-based electromagnetic interference (EMI) shielding materials receive increasing attention undoubtedly. However, there is still a challenge to use raw biomass materials to construct a significant structure through an effortless and environmental route for EMI shielding applications. Herein, for the first time, we demonstrated a hybrid composite of multi-walled carbon nanotube/polypyrrole/chrome-tanned collagen fiber (MWCNT/PPy/CF), which utilized waste chrome shavings as a matrix. X-ray photoelectron spectroscopy reveals that the chromium on the CF has a binding effect on the PPy layer, which endows the tight integration between the CF and PPy layer. After the MWCNT network was loaded on the PPy layer, this ternary structure could provide stable conductive paths and a rich number of polarized interfaces. The MWCNT/PPy/CF composite exhibits superior electrical conductivity (354 ± 52 S/m), higher than PPy/CF (222 ± 38 S/m) and MWCNT/CF (104 ± 11 S/m), owing to the synergy of dual conductive structures. Notably, the shielding effectiveness (SE) value of the MWCNT/PPy/CF composite reaches 30 dB in the X band at a thickness of 0.48 mm. The shielding effectiveness of reflection (SER) (9.1 dB) is similar to that of PPy/CF (8.2 dB), while the shielding effectiveness of absorption (SEA) is significantly improved from 15.3 dB (PPy/CF) to 20.4 dB (MWCNT/PPy/CF) due to the additional coverage of the MWCNT network. This indicates the synergy between the MWCNT network and conductive PPy/CF skeleton. This work provided a method to prepare sustainable and low-cost renewable EMI shielding materials using chrome shavings. Meanwhile, this novel structure combining a conductive skeleton and heterostructure can be considered as a potential application in relevant fields.

Multiwalled carbon nanotubes filled thermoplastic vulcanizate dielectric elastomer with excellent resilience properties via inhibiting MWCNT network formation

AbstractMultiwalled carbon nanotubes (MWCNTs) filled thermoplastic vulcanizate (TPV) dielectric elastomer based on polypropylene (PP)/ethylene‐propylene‐diene monomer blends were fabricated via a simple melt compounding. MWCNT could be selectively distributed in PP matrix which induced by the dynamic vulcanization reaction. By reducing the rotor speed of melting blending to 60 rpm, the MWCNT network formation can be effectively inhibited, which have been verified by a higher volume resistivity (above 109 Ω cm). With increasing the MWCNTs loading to 4.1 vol%, a maximum increase, 423.4% (from 3.04 to 12.87), of the dielectric constant have been achieved for TPV/MWCNTs elastomer at 103 Hz, while the dielectric loss is still lower than 0.072 at 101–103 Hz. Meanwhile, with various MWCNTs loading, the tensile recovery of these series TPV elastomer does not change anymore, resulting an excellent rebound resistance. The TPV elastomer exhibits an enhanced dielectric performance and balanced elastic recovery performance, providing a simple and scalable melt compounding approach to fabricate high‐performance dielectric elastomer.

Screen printed novel ZnO/MWCNTs nanocomposite thick films

Zinc oxide and multiwall carbon nanotubes (ZnO/MWCNT) nanocomposites thick films were prepared via sol-gel screen printing procedure and followed by sintering at 550 °C. Thus, the prepared films were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), Ultraviolet–visible (UV–vis), Photoluminescence (PL), Fourier transform infrared (FTIR), Raman spectroscopy and Two-probe method. XRD analysis revealed (101) orientation for both ZnO and ZnO/MWCNT thick films with wurtzite structure. SEM studies confirmed the porous nature of ZnO film while ZnO/MWCNT films showed ZnO particles trapped in the porous MWCNT network and free from cracks. Reflectance spectroscopy showed direct transition with decreasing band gap whereas refractive index and absorption index showed appreciable variation within the band gap regime related to the change in crystallite size. FTIR profile approved the Zn–O stretching and presence of carboxylic CDC group. The PL spectrum of ZnO and ZnO/MWCNT thick films shows red shift and exhibits UV, blue and green emissions confirmed from CIE diagram. Raman spectrum shows that Raman phonons are shifted and dominated due to doping of MWCNT in ZnO matrix. Electrical properties were investigated using 2-probe method and showed a reduction in resistance on MWCNT incorporation. The novelty of current-work is the fabrication of ZnO/MWCNT through a low-cost screen printing process for the first time and the results exhibits that the bandgap of the deposited film is decreased, which in turn, play a significant role in enhancement of conductivity and colour emission for fabrication of low cost optoelectronics devices (LEDs) as compared with the pure ZnO film.

Tuning the Structure and Performance of Bulk and Porous Vapor Sensors Based on Co-continuous Carbon Nanotube-Filled Blends of Poly(vinylidene fluoride) and Polycarbonates by Varying Melt Viscosity.

This work describes a new concept of porous vapor sensor materials based on co-continuous polycarbonate/poly(vinylidene fluoride)/multiwalled carbon nanotube (PC/PVDF/MWCNT) blend composites. The blend composites were fabricated by melt mixing in a one-step mixing process, and the MWCNT containing component (here PC) was extracted, leaving a MWCNT network on the continuous surface of the remaining component (here PVDF). First, by selecting three PCs with different molecular weights, the blend viscosity ratio and blend fineness and interfacial area were varied. At the chosen blend composition of 40/60 wt %, the desired co-continuous structure was achieved with MWCNTs selectively localized in PC. The conductive polymer composites (CPCs) with low-viscosity PC had the highest conductivity due to a combination of the best MWCNT dispersion and the coarsest blend morphology. The vapor sensing of CPC sensor materials with 1 wt % MWCNT was tested using saturated vapors of dichloromethane, acetone, tetrahydrofuran, and ethyl acetate, showing good interaction with PC. The compact compression molded CPC materials with low-viscosity PC showed the lowest relative resistance changes (Rrel) during the cyclic sensing tests, but a better recovery compared to corresponding CPCs with medium and high viscosity PC. The porous CPC sensors showed remarkable vapor sensing performance compared to the corresponding compact sensors with better sensing stability, reproducibility, and reversibility. Scanning electron microscopy (SEM) confirmed that a fraction of the nanotubes remained on the surface of the continuous, nonsoluble PVDF after PC extraction. The porous sensor material from which the low-viscosity PC was extracted showed the highest Rrel (e.g., around 1300% after 100 s immersion in acetone vapor) compared to all other organic vapors investigated. The difference in vapor measurement between compact and porous sensor materials was attributed to the different sensing mechanisms of polymer swelling for the compact and vapor absorption on the free CNT networks for the porous samples.

Highly Sensitive Room-Temperature NO2 Gas Sensors Based on Three-Dimensional Multiwalled Carbon Nanotube Networks on SiO2 Nanospheres

The electrical conductivity of carbon nanotubes (CNTs) has been demonstrated to be highly sensitive to the change of vapor/gas molecules in the local environment owing to the large specific surface area and quantum size effect, which enable CNTs to be an ideal sensing material for next-generation room-temperature gas sensors. However, the sensing properties of CNT films or networks cannot be maximized because of the inevitable agglomeration during the fabrication process. Herein, three-dimensional (3D) SiO₂@multiwalled CNTs (MWCNTs) core–shell nanospheres have been first used to fabricate room-temperature gas sensors, which were prepared using an electrostatic self-assembly method. The as-fabricated 3D SiO₂@MWCNTs sensor exhibits a recorded sensitivity of 82.61% toward 1 ppm nitrogen dioxide (NO₂) at room temperature, which is 1.97 times higher than that of devices based on random two-dimensional (2D) MWCNTs. Meanwhile, the recovery time of ∼44 s is smaller than that of a 2D MWCNT gas sensor. Such an ultrahigh sensing performance is attributed to an effective utilization of the large specific surface area of MWCNT networks with 3D structures. We believe that our findings will contribute to the further development of high-performance CNT-based sensing devices and also provide a new approach to fabricate the sensing devices using one-dimensional nanomaterials.

Lichen-like anchoring of MoSe2 on functionalized multiwalled carbon nanotubes: an efficient electrode for asymmetric supercapacitors.

In the present study, we have developed a composite electrode of MSNT using a simple and scalable two-step scheme to synthesize a composite electrode material comprising MoSe2/multiwalled carbon nanotubes (MoSe2/MWCNTs) for supercapacitor applications. First, a MWCNT thin film was deposited on a stainless steel substrate by using a “dip and dry” coating technique. Subsequently, MoSe2 was deposited onto the MWCNT thin film using the successive ionic layer adsorption and reaction method. The lichen-like growth of MoSe2 on the MWCNT network provided dual charge storage and an effective ion transfer path. The composite electrode of MSNT has been studied systematically with different electrolytes and concentrations of electrolyte. As a result, the MoSe2/MWCNT (MSNT) electrode exhibited excellent electrochemical properties such as a specific capacity of 192 mA h g−1 and a capacitance retention of 88% after 2000 cycles in 1 M LiCl electrolyte. The results demonstrated the huge potential of the MSNT composite electrode for practical application in supercapacitors. The aqueous symmetric cell fabricated using the MSNT composite as both the anode and cathode showed an energy density of 17.9 W h kg−1. Additionally, the energy density improved by designing an asymmetric device of MSNT//MnO2 and notably, it reveals two-fold improvement in the energy density compared to a symmetric MSNT cell. The MSNT//MnO2-based asymmetric cell exhibited a maximum specific capacitance of 112 F g−1 with a high energy density of 35.6 W h kg−1.

Morphology correlated investigation on mechanical and dielectric properties of plasticized poly vinyl chloride/MWCNT nanocomposites

This paper investigates the correlation of morphologies with mechanical and dielectric properties of plasticized poly vinyl chloride/MWCNT (PPVCN) nanocomposites. Special focus is given to filler induced networking and its effect on the dielectric properties of nanocomposites. Mechanical properties with different MWCNT loadings from 0.25% to 5% are correlated with fracture morphologies to understand the fracture mechanism and factors influencing the mechanical properties of the nanocomposites. At 5% MWCNT loading, the nanocomposite shows improvement in strength with exceptional enhancement in modulus. The best mechanical properties of the nanocomposite at 5% MWCNT loading is supported by morphological features, such as matrix cracks and crack bridging by MWCNTs. These features also supported the enhancement in toughness of the nanocomposite imparted by better polymer/MWCNT interfacial interactions. The dielectric properties of nanocomposites increase with increasing MWCNT loading. The nanocomposite with 5% MWCNT loading shows a six times high filler contribution factor when the system reaches its percolation limit. This supports the idea that polymer bridged MWCNT network formation has a pronouncing effect on the permittivity of the nanocomposites. PPVCN nanocomposite with 5% MWCNT loading exhibits the best mechanical and dielectric properties.

Improved static and dynamic mechanical properties of multiscale bucky paper interleaved Kevlar fiber composites

Herein, the influence of bucky paper interleaves and dispersed MWCNT network on static and dynamic mechanical properties of Kevlar-epoxy composites, subjected to different loading conditions is investigated. Multiscale hybrid laminar Kevlar composites are prepared by vacuum impregnation followed by compression moulding technique. Subsequently, these hybrid composites are subjected to tensile, flexural, dynamic mechanical and low velocity impact and directly compared with basic Kevlar composite (KE) laminate. It is found that bucky paper interleaves along with dispersed MWCNT (KEBC) improve interlaminar and interfacial properties respectively. It is found that the maximum dynamic impact energy absorption and load carrying capacity of KEBC increase to 13.8 J and 2650 N respectively which shows an overall improvement of 31% over KE. These results are further confirmed by Charpy's impact test, in which maximum impact toughness reaches to 90.4 J/mm2, which is consistent with dynamic impact test results. After conducting various lab scale mechanical tests, ballistic test is also performed over KEBC and KE. It is found that, in case of KEBC, back face signature is reduced to 30% over KE, which confirms the collective effort of bucky paper interleaves and dispersed MWCNT in enhancing the energy absorption capability of hybrid laminar composite.

A polar TiO/MWCNT coating on a separator significantly suppress the shuttle effect in a lithium-sulfur battery

Lithium-sulfur (Li-S) batteries are extremely attractive because of their high theoretical capacities, energy densities, and cost-effectiveness, as well as the environmental friendliness of elemental sulfur. However, the commercialization of Li-S batteries is impeded by fast capacity fading and harsh self-discharge. To overcome these issues, effort has been dedicated to improving performance by designing the electrode structure and composition, which is often expensive and complex. In this study, modification of the separator by a combination of commercial titanium monoxide and multiwall carbon nanotubes (TiO/MWCNTs) was first designed, which is a low-cost and simple preparation process. The cooperative effect of TiO and MWCNTs capacitates the feedback of the Li-S cell with a relatively high premier discharge capacity of 1527.2 mAh g −1 , and excellent cycling stability is obtained up to 1000 cycles at 0.5 C with a negligible fading rate of 0.057% per cycle. And the self-discharge behavior was improved obviously. When the time of rest was extended to 96 h, the capacity attenuation of the cell with the TiO/MWCNT coating was only 12.4%. The use of a TiO/MWCNT-coated separator is a feasible method for the commercial success of high-performance Li-S batteries. • TiO/MWCNT composite is firstly used to modify the separator of Li-S battery. • High density of oxygen and titanium vacancies of TiO is benefit for adsorbing LiPSs. • MWCNT network as a physical barrier improves the conductivity of the separator. • The strong adsorption of TiO/MWCNT suppress the shuttle effect of Li-S battery.