Multi-walled Carbon Nanotubes Research Articles

Enhancing thermo-physical properties of hybrid nanoparticle-infused medium temperature organic phase change materials using graphene nanoplatelets and multiwall carbon nanotubes

Phase change materials (PCMs) have emerged as an intriguing option for the storage of thermal energy because of their remarkable capacity to store latent heat. However, the practical application of these materials is hindered by their low thermal conductivity and limited photo-absorbance. For this investigation, graphene nanoplatelets (GNP) and multiwall carbon nanotubes (MWCNT) hybrid nanoparticles were disseminated in RT-54HC organic PCMs at different weight fractions. The nanoparticles were incorporated into the base PCMs using a melt blending technique. Based on the findings, one combination of GNP to MWCNT in a 0.25:0.75 ratio has shown the highest thermal conductivity, with an increase of 40% (0.28 Wm−1 K−1) compared to other hybrid combinations. This breakthrough could potentially open new avenues in the field of thermal energy storage. The chemical stability of the hybrid nanoparticle dispersed composites was assessed through FTIR analysis. In addition, the composites exhibited excellent thermal stability, maintaining their structural integrity even at temperatures as high as 300 ℃. The melting temperature of the composites also showed minimal variation. Based on the evaluation of latent heat enthalpy, the organic PCM known as base RT-54HC demonstrated a heat storage capacity of 230 J/g. However, the composites exhibited a slight decrease in latent heat with increasing nanoparticle weight fraction. In addition, the composite with added hybrid nanoparticles demonstrated an increase in optical absorbance, accompanied by a decrease in transmissibility. Therefore, the hybrid nano-enhanced composites have demonstrated enhanced thermo-physical properties, making them not only suitable but also highly promising for use in applications with mid-range melting temperatures.Graphical

Synthesis of Rod‐Like Sb2Se3@MWCNT as Conductive‐Additive Free Anode for Sodium‐Ion Batteries

AbstractAntimony selenide (Sb2Se3) is a promising electrode material for sodium‐ion batteries (SIBs) due to its high theoretical capacity. However, volume expansion during sodiation/desodiation and the low conductivity of Sb2Se3 reduce the electrochemical performance. Herein, we synthesized Sb2Se3 nanorods (NRs) and combined them with multi‐walled carbon nanotubes (MWCNTs) using one‐step composite process to address these issues. MWCNTs can accommodate volume expansion and provide high conductivity. The fabricated Sb2Se3 NRs@MWCNT electrode exhibits improved cycle performance and cyclic stability without additional conductive carbons. The Sb2Se3 NRs@MWCNT electrode showed an enhanced specific capacity of 440 mAhg−1 at a current density of 0.1 Ag−1, compared to 220 mAhg−1 for the Sb2Se3 NRs electrode. Additionally, it exhibited good stability at high current density. The in‐situ electrochemical impedance spectroscopy (EIS) and Galvanostatic intermittent titration technique (GITT) were used to estimate the electrochemical properties and kinetics of Sb2Se3 NRs@MWCNT. These results showed that Sb2Se3 NRs@MWCNT have the potential as a conductive‐free anode material in SIBs.

Plasticizers: distribution and impact in aquatic and terrestrial environments.

Plasticizers, essential additives for enhancing plastic properties, have emerged as significant environmental and health concerns due to their persistence and widespread use. This study provides an in-depth exploration of plasticizers, focusing on their types, structures, properties, production methods, environmental distribution, and associated risks. The findings reveal that petroleum-based phthalates, particularly di-(2-ethylhexyl) phthalate (DEHP), are prevalent in aquatic and terrestrial environments, primarily due to the gradual degradation of plastic polymers. In the analysis of 39 studies on water contamination during the period of 2022-2023, only 22 works could be extracted due to insufficient details on the numerical value of plasticizer concentrations. Similarly, soil and sediment contamination studies were fewer, with only 11 studies focusing on sediments. These studies reveal that high plasticizer concentrations, notably in industrial and urban areas, often exceed recommended environmental limits, posing risks to ecological integrity and human health through bioaccumulation. Bioaccumulation of these compounds in soil and water could negatively affect the microbial communities, nutrient cycling, and could destabilize the overall ecological integrity. Concerns about their direct uptake by plants and potential risks to human health and food safety are highlighted in this study due to the high concentrations exceeding the threshold values. The review evaluates current treatment technologies, including metal-organic frameworks, electrochemical systems, multi-walled carbon nanotubes, and microbial degradation, noting their potential and challenges related to cost and energy consumption. It underscores the need for improved detection protocols, cost-effective treatments, stricter regulations, public awareness, and collaborative research to mitigate the adverse impacts of plasticizers on ecosystems and human health.

MHD double diffusive convective squeezing ternary nanofluid flow between parallel plates with activation energy and viscous dissipation

Purpose This study aims to present the consequences of activation energy and the chemical reactions on the unsteady MHD squeezing flow of an incompressible ternary hybrid nanofluid (THN) comprising magnetite (FE3O4), multiwalled carbon nano-tubes (MWCNT) and copper (Cu) along with water (H2O) as the base fluid. This investigation is performed within the framework of two moving parallel plates under the influence of magnetic field and viscous dissipation. Design/methodology/approach Due to the complementary benefits of nanoparticles, THN is used to augment the heat transmit fluid’s efficacy. The flow situation is expressed as a system of dimensionless, nonlinear partial differential equations, which are reduced to a set of nonlinear ordinary differential equations (ODEs) by suitable similarity substitutions. These transformed ODEs are then solved through a semianalytical technique called differential transform method (DTM). The effects of several changing physical parameters on the flow, temperature, concentration and the substantial measures of interest have been deliberated through graphs. This study verifies the reliability of the results by performing a comparison analysis with prior researches. Findings The enhanced activation energy results in improved concentration distribution and declined Sherwood number. Enhancement in chemical reaction parameter causes disparities in concentration of the ternary nanofluid. When the Hartmann number is zero, value of skin friction is high, but Nusselt and Sherwood numbers values are small. Rising nanoparticles concentrations correspond to a boost in overall thermal conductivity, causing reduced temperature profile. Research limitations/implications Due to its firm and simple nature, its implications are in various fields like chemical industry and medical industry for designing practical problems into mathematical models and experimental analysis. Practical implications Deployment of the squeezed flow of ternary nanofluid with activation energy has significant consideration in nuclear reactors, vehicles, manufacturing facilities and engineering environments. Social implications This study would be contributing significantly in the field of medical technology for treating cancer through hyperthermia treatment, and in industrial processes like water desalination and purification. Originality/value In this problem, a semianalytical approach called DTM is adopted to explore the consequences of activation energy and chemical reactions on the squeezing flow of ternary nanofluid.

Superhydrophobic anti-icing/de-icing SR/CNTs surfaces hot-embossed with femtosecond laser machined mold

Anti-icing/de-icing surfaces are dispensable in reducing accidents and economic losses caused by accumulated ice and frost on outdoor facilities in cold and humid environments. In this work, a low-cost, reproducible process was presented to fabricate superhydrophobic anti-icing/de-icing surfaces. For this purpose, concave micro-structures were firstly created on the mold steel surface using femtosecond laser machining, and then the corresponding convex micro-structures were prepared on the surface of a silicone rubber (SR) composite mixed with multi-wall carbon nanotubes (CNTs) using hot embossing. Thanks to the presence of unique micro-scale peak-ridge structures, the as-prepared SR/CNTs surfaces possess superhydrophobic characteristic. Long icing delay time was endowed by the large volume of air pockets inside micro-structures, and the icing time was significantly extended from 67 to 416 s, which is ascribed to the greatly inhibited heat transfer between the droplet and the surface. Moreover, the SR/CNTs surface had excellent photothermal conversion capability with the presence of photothermal particles CNTs, and the temperature of the surface increased rapidly from 21.6 to 86.1 °C in 5 min under a standard sunlight irradiation. In addition, the SR/CNTs surface also possesses superior photothermal defrosting and de-icing performance as the ice and frost on the surface can be quickly melted under a standard sunlight intensity irradiation and the de-icing rate is up to 0.92 mg/s. Finally, the good reusability of the mold steel and the resistance to mechanical wear and chemical corrosion of superhydrophobic SR/CNTs surface found in this work make the proposed approach promising for industrial mass production and anti-icing/de-icing applications in harsh environments.

Microwave Ignition of Thermites

AbstractThis study investigates the microwave ignition behavior of a range of thermites of aluminum, boron, titanium, and tantalum fuels with oxides of Bi2O3, CuO, and Fe2O3. In order to gain insight into the modes of energy transfer leading to ignition, thermites are heated in either a purely electric or magnetic field environment within a single‐mode 2.45 GHz resonant cavity with electric field strengths of 40 to 110 kV/m and magnetic field strengths of 22 to 258 A/m. Thermite stoichiometry is varied as well as particle size and thermite mass. The shortest ignition delays in electric and magnetic fields were found to be 1.37 s (nAl and CuO) and 0.87 s (nAl and CuO), respectively. The use of a variety of carbon susceptors to shorten ignition delay is also studied. Carbon susceptors are found to appreciably shorten ignition delays to as short as 140 and 170 ms for the E and B field respectively (nAl and CuO with multiwalled carbon nanotubes). The results of this work are informative on thermite component choice and the preferred mechanism (electric vs magnetic field) of heating for various thermite compositions for consideration of the increasingly popular ignition via electromagnetic fields.

Dual-Mode cellulose acetate@Al2O3/MWCNTs Janus fabric with radiative cooling and solar heating for personal thermal management

Personal thermal management (PTM) textiles with heating and cooling functionalities are highly appealing due to their potential to offer personalized comfort while also contributing to decrease energy consumption. However, most PTM fabrics are static and unable to meet the human body’s thermal comfort needs during seasonal and ambient temperature fluctuations. Herein, this work presents a dual-mode Janus Metafabric to provide radiation cooling and solar heating. The cooling side of Metafabric (cellulose acetate@Al2O3 porous coating) offers high solar reflectance (92.12 %), infrared emissivity (83.22 %), and net cooling power of 55.85 W·m−2. The heating side (multi-walled carbon nanotubes) exhibits a high solar absorption rate (88.4 %). Compared with raw fabric, it can achieve an additional cooling of 4.58 °C and heating of 38.02 °C. In addition, Metafabric also have excellent ultraviolet resistance, wear resistance, and washing properties, making it suitable for practical wearing. By flipping the Janus fabric, it is easy to switch between the cooling and heating modes to adapt to dynamic ambient temperature changes, which have great potential for maintaining human thermal comfort and alleviating the energy crisis.

Enhancing tin foil anodes in lithium-ion batteries through carbon nanotube integration via rolling technique

In this study, we propose the use of multi-walled carbon nanotubes (MWCNTs) combinded with accumulative roll bonding technique to enhance the performance of Sn foils as anodes in lithium-ion batteries. Increasing the amount of CNTs reduces the grain size of Sn, which leads to an increase in hardness. As the CNT content increases from 0 to 2.2 wt%, several electrochemical improvements are observed: decreased nucleation overpotential, enhanced Coulombic efficiency, reduced overpotential, lowered charge transfer resistance, and increased lithium-ion diffusivity. These combined effects synergistically enhance the capacity of the anode. The benefits of incorporating CNTs into Sn can be attributed to two main factors: (1) the increased grain boundaries, dislocations, and CNTs provide more active sites for (de)lithiation and facilitate faster lithium-ion diffusion paths; (2) the improved strength resulting from grain refinement and CNT reinforcements helps maintain structural integrity during the formation and growth of high-density pores over multiple cycles. Although the addition of CNTs enhances capacity up to a content of 0.9 wt%, further additions result in a stagnation in capacity enhancement. Furthermore, when the CNT content exceeds 0.6 wt%, cyclic life, capacity retention, and rate capabilities significantly decline due to increased CNT agglomeration.

A Machine Learning Assisted Non-Enzymatic Electrochemical Biosensor to Detect Urea Based on Multi-Walled Carbon Nanotube Functionalized with Copper Oxide Micro-Flowers.

Detecting urea is crucial for diagnosing related health conditions and ensuring timely medical intervention. The addition of machine learning (ML) technologies has completely changed the field of biochemical sensing, providing enhanced accuracy and reliability. In the present work, an ML-assisted screen-printed, flexible, electrochemical, non-enzymatic biosensor was proposed to quantify urea concentrations. For the detection of urea, the biosensor was modified with a multi-walled carbon nanotube-zinc oxide (MWCNT-ZnO) nanocomposite functionalized with copper oxide (CuO) micro-flowers (MFs). Further, the CuO-MFs were synthesized using a standard sol-gel approach, and the obtained particles were subjected to various characterization techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectroscopy. The sensor's performance for urea detection was evaluated by assessing the dependence of peak currents on analyte concentration using cyclic voltammetry (CV) at different scan rates of 50, 75, and 100 mV/s. The designed non-enzymatic biosensor showed an acceptable linear range of operation of 0.5-8 mM, and the limit of detection (LoD) observed was 78.479 nM, which is well aligned with the urea concentration found in human blood and exhibits a good sensitivity of 117.98 mA mM-1 cm-2. Additionally, different regression-based ML models were applied to determine CV parameters to predict urea concentrations experimentally. ML significantly improves the accuracy and reliability of screen-printed biosensors, enabling accurate predictions of urea levels. Finally, the combination of ML and biosensor design emphasizes not only the high sensitivity and accuracy of the sensor but also its potential for complex non-enzymatic urea detection applications. Future advancements in accurate biochemical sensing technologies are made possible by this strong and dependable methodology.

Environmentally Friendly, Dual-Responsive Actuator Based on Nafion, Carboxylated Multiwalled Carbon Nanotubes, and Polyethylene.

As a type of smart material, flexible stimulus-responsive actuators have become a hot research topic nowadays. However, flexible actuators responding to a single stimulus source are susceptible to external perturbations, which may lead to an unstable function or even failure. Therefore, in this paper, we proposed a bilayer actuator that can be driven by both humidity and light by combining the humidity-sensitive Nafion, carboxylated multiwalled carbon nanotubes (cMWCNT) with excellent photothermal conversion properties, and commercial polyethylene (PE) tape with good humidity insensitivity and thermal expansion. First, the cMWCNT-Nafion film was prepared by a solution casting method and bonded together with PE tape to obtain a bilayer actuator. Then, the effects of the cMWCNT mass fraction and film thickness on the humidity and light response performance of the bilayer actuator were investigated. The optimal ratios of raw materials were obtained for different stimulation sources, respectively. Furthermore, the performance of the bilayer actuator with the optimal ratios was tested; it was verified that the proposed dual-responsive actuator can realize different degrees of bending deformation under different relative humidity (RH) and ultraviolet (UV) light intensity with good stability. Finally, the application potential in multiple scenarios was further verified by applying the prepared cMWCNT-Nafion/PE bilayer actuator to a smart window, crawling robot, and flexible gripper. This paper will provide a meaningful reference for the development and performance optimization of high-performance dual-responsive actuators.

Catalytic activities of tannase covalently linked to amino-functionalized carbon nanotubes

Immobilized Aspergillus ficuum tannase on amino-functionalized multiwalled carbon nanotubes (A-MWCNT) was assembled through glutaraldehyde-mediated covalent coupling to produce a stable biocatalyst nanocomposite. The effective binding of tannase on the surface of A-MWCNT was evaluated and authenticated by spectroscopic signature signals and morphological differences, before and after enzyme coupling. Both free- and immobilized tannase showed optimal catalytic activities at pH 5.0 and 35 °C, with the immobilized tannase exhibiting enhanced thermostability compared to the soluble enzyme. The immobilized tannase preparation was also found to be reusable up to five cycles, with 66% of initial enzyme activity retained thereafter. The enzyme-carbon nanotube composite preparation allows for bioconversion to be accomplished in a bioreactor with a smaller footprint.

Activation mechanism of persulfate by Fe3C-based materials for efficient benzo-a-pyrene abatement in wastewater: The reversed direct electron transfer from persulfate to contaminants

Herein, an unusual reserved direct electron transfer (r-DET) process from persulfate (PS) to contaminants was observed on the surface of Fe3C with N-doped C shell supported on carbon nanotubes (Fe3C@CN-CNTs). The Fe3C-based materials were synthesized via a facile sol–gel method employing melamine, glucose, FeCl3, and commercial multi-walled CNTs. The activation mechanisms were fully explored with a comparison of Fe3C@CN-CNTs and other Fe3C-based materials for the effective abatement of benzo-a-pyrene (BaP), a typical persistent organic pollutant in industrial wastewater. Electrochemical measurements, zeta potential monitoring, and Mössbauer spectroscopy indicated that the lack of CN shell result the relatively large particle size of Fe3C on Fe3C-CNTs, leading to more negatively charged surface and abundant OH during PS activation. Nevertheless, the superparamagnetic fraction with a fine particle size on the surface of Fe3C@CN and Fe3C@CN-CNTs potentially leads to a more positively charged surface, enhancing the zeta potential of surface adsorbed BaP and benefiting the r-DET. Through r-DET, oxidized PS and reduced BaP formed as intermediates, accelerating the overall degradation of BaP in Fe3C@CN-CNTs/PS. The degradation pathways, cytotoxicity, and operation conditions of BaP degradation by Fe3C@CN-CNTs/PS were thoroughly investigated. Additionally, Fe3C@CN-CNTs were found to promote the nucleophilic reaction between Cl− and PS, producing free chlorine and enhancing BaP degradation efficiency in chloride-containing wastewater. Overall, this study presents a new insight for the PS-based r-DET process and offers a promising approach for treating organically-contaminated wastewater.

Microstructure-mechanical property relationships of polymer nanocomposite reinforced with lyophilized montmorillonite/carbon nanotubes hybrid particles

Abstract Introducing multi-walled carbon nanotubes (MWCNT) and montmorillonite (MMT) simultaneously into a polymer can significantly enhance its properties. Meanwhile, choosing the best technique to homogeneously disperse these nanohybrid particles in polymers, without agglomerates, is still a challenge. In this study, a hybrid MMT/MWCNT, prepared by lyophilization process, is introduced in polylactide (PLA). Morphology of the resulting nanocomposites displays synergistic relationships of the MMT/MWCNT, facilitating dispersion in PLA. The analysis of transmission electron microscopy (TEM) specific particle densities of PLA0.5hyb, PLA1.0hyb, and PLA2.0hyb shows values of 77, 64, and 35 µm⁻2, respectively. This suggests that MMT platelets are significantly more exfoliated in PLA0.5hyb compared to the other nanocomposites. It also indicates that filler aggregation increases as the MMT/MWCNT concentration increases. Compared to neat PLA, elastic modulus of nanocomposites increased by up to 46 %, demonstrating the reinforcing effect of MMT/MWCNT hybrid nanofillers. The nanocomposites exhibit viscosity, plasticity and damage phenomena, which are significantly decreased because of the MMT/MWCNT incorporation, compared to neat PLA. Furthermore, the viscoelastic properties, analyzed by dynamic thermal-mechanical analysis, record about 27 % increase in the storage modulus of the nanocomposites compared to PLA, indicating the effectiveness of the hybrid MMT/MWCNT in increasing the resistance of PLA/MMT/MWCNT nanocomposite against thermomechanical aggression.

Robust biomimetic strain sensor based on butterfly wing-derived skeleton structure

A biomimetic strain sensor was designed and constructed based on Ir nanoparticles-modified multi-wall carbon nanotubes (Ir NPs@MWCNTs) and parallel Pt layer/dragon skin with carbonized butterfly wing patterns. This sensor exhibits high gauge factor (∼515.4), extensive tensile range (0%–96%), and swift response (∼300 ms), especially remarkable stability up to 60 000 cycles. The work mechanism has been proposed based on the experimental test and finite-element method. Some important applications such as human motion and micro-expression recognition have been confirmed using 3 × 3 flexible biomimetic sensor array.

Experimental investigation of dodecanoic acid–tetradecanoic acid–dodecanol ternary mixture based nanoparticle enriched-phase change material for food preservation applications

In this research, a novel phase change material (PCM), containing dodecanoic acid-tetradecanoic acid-dodecanol ternary mixture, designated as pure mixture, dispersed with two carbon-based nanoparticles, i.e., graphene nanoplatelets - multiwall carbon nanotube and graphene nanoplatelets-titanium dioxide, with 1% weight fraction, is prepared and is designated as nanoparticle-enriched-phase change material. The chemical and thermal analysis of pure ternary mixture and nanoparticle-enriched-phase change material was conducted using X-ray diffraction, Scanning electron microscopy, Differential scanning calorimetry, Fourier transform infrared, Thermo gravimetric analyser and Thermal conductivity analyser techniques. The pure mixture possess melting and freezing temperature of 15.6°C and 8.4°C with a melting-freezing latent heat (LH) of 131.5 J/g and 125.4 J/g, respectively. The thermal conductivity exhibited a significant increase of 187.6% in the case of pure mixture with graphene nanoplatelets- multiwall carbon nanotube and 41.7% for pure mixture with graphene nanoplatelets-titanium dioxide. Moreover, the PCM remained thermally stable in both cases, even with the incorporation of nanoparticles. The melting as well as freezing LHs were reduced by about 18.17% and 18.02% for graphene nanoplatelets- multiwall carbon nanotube dispersed PCM and, 12.49% and 9.49% for graphene nanoplatelets- titanium dioxide dispersed PCM, respectively, in comparison with the pure mixture. Similarly, the melting/freezing temperatures, gets also reduced by 9.6%/8.3% and 10.9%/8.3%, respectively, for both mixtures. The pure mixture with graphene nanoplatelets- multiwall carbon nanotube exhibited a substantial decrease in both charging and discharging times, with reductions of 28.48% and 18.73%, respectively, in comparison to pure mixture, at an air inlet velocity of 3 m/s.

An amplified voltammetric immunosensor for detection of porcine serum albumin using a self-standing nanohybrid composed of multi-walled carbon nanotubes, polyelectrolytes, and gold nanoparticles

Here, we introduce an innovative approach for signal amplification of a voltammetric immunosensor platform with nanoporous alumina (NPA) millirods to specifically target porcine serum albumin (PSA). A self-standing nanohybrid was constructed using a layer-by-layer assembly technique, which involved coating multi-walled carbon nanotube (MWCNTs) with polyelectrolytes (PEs) and subsequent attachment of multiple gold nanoparticles (AuNPs). The PEs improved dispersion of the MWCNTs and facilitated attachment to multiple AuNPs for enhanced bioconjugation with anti-PSA detection (α-PSAD) antibodies. The morphology of the nanohybrid was examined using field-emission scanning electron microscopy. The resulting MWCNT/PE/AuNP/α-PSAD-bioconjugated nanohybrid acted as an amplified signaling probe for the PSA-specific, NPA millirod-based voltammetric immunosensor. A current value recorded at +0.68 V (vs. Ag/AgCl reference electrode) in the voltammogram served as the analytical signal for quantification, thereby eliminating the need to analyze peak characteristics. Demonstrating remarkable sensitivity, the nanohybrid achieved a PSA detection limit of 0.5 pg/mL, surpassing the 50 pg/mL limit of an immunosensor using a single AuNP for signaling. The proposed nanohybrid offers a superior solution for highly sensitive detection of PSA in voltammetric immunosensor applications.

The importance of factorial design on the optimization of biosensor performance: immobilization of glucose oxidase as a case study.

Conventionally, the optimization of glucose biosensors is achieved by varying the concentrations of the individual reagents used to immobilize the enzyme. In this work, the effect and interaction between glucose oxidase enzyme (GOx), ferrocene methanol (Fc), and multi-walled carbon nanotubes (MWCNTs) at different concentrations were investigated by a design of experiments (DoE). For this analysis, a factorial design with three factors and two levels each was used with the software RStudio for statistical analysis. The data were obtained by electrochemical experiments on the immobilization of GOx-Fc/MWCNT at different concentrations. The results showed that the factorial DoE method was confirmed by the non-normality of the residuals and the outliers of the experiment. When examining the effects of the variables, analyzing the half-normal distribution and the effects and contrasts for GOx-Fc/MWCNT, the factors that showed the greatest influence on the electrochemical response were GOx, MWCNT, Fc, and MWCNT:Fc, and there is a high correlation between the factors GOx, MWCNT, Fc, and MWCNT:Fc, as shown by the analysis of homoscedasticity and multicollinearity. With these statistical analyses and experimental designs, it was possible to find the optimal conditions for different factors: 10mMmL-1 GOx, 2mgmL-1 Fc, and 15mgmL-1 MWCNT show a greater amperometric response in the glucose oxidation. This work contributes to advancing enzyme immobilization strategies for glucose biosensor applications. Systematic investigation of DoE leads to optimized immobilization for GOx, enables better performance as a glucose biosensor, and allows the prediction of some outcomes.

Tuning Dielectric Properties with Nanofiller Dimensionality in Polymer Nanocomposites.

Polymer nanocomposites hold great potential as dielectrics for energy storage devices and flexible electronics. The structural architecture of the nanofillers is expected to play a crucial role in the fundamental mechanisms governing the electrical breakdown and dielectric properties of the nanocomposites. However, the effect of nanofiller structure and dimensionality on these properties has not been studied thoroughly to date. This study explores the critical relationship between nanofiller dimensionality and dielectric properties in polymer nanocomposites. We fabricated polyvinylidene fluoride (PVDF) nanocomposites by incorporating a range of carbon-based nanofillers separately, including zero-dimensional (0D) carbon black (CB), one-dimensional (1D) multiwalled carbon nanotubes (MWCNT), 1D single-walled carbon nanotubes (SWCNT), two-dimensional (2D) reduced graphene oxide (rGO), and three-dimensional (3D) graphite. The frequency-dependent (1 kHz to 1 MHz) dielectric permittivity (k) of the nanocomposites at the same concentration of nanofillers demonstrated a hierarchical order, with MWCNT showing the highest permittivity (∼400%), succeeded by rGO (∼360%), CB (∼290%), SWCNT (∼230%), and graphite (∼70%), respectively. The temperature-dependent (50-150 °C) dielectric spectroscopy revealed high k with increasing temperature due to the enhanced dipole movement. However, their dielectric breakdown strength and energy densities were not correlated to k and exhibited the following order: SWCNT > MWCNT > CB > rGO > graphite. As the electrical breakdown depends upon the nanocomposites' mechanical strength, we correlated the mechanical properties with the nanofiller dimensionality, and Young's modulus followed the 1D ≈ 2D > 0D > 3D order. These findings will provide fundamental insights into designing tunable, conducive nanofiller-based nanocomposites in next-generation flexible electronics and capacitive energy storage devices.

CARBON NANOTUBES AS EFFECTIVE REMEDY FOR THIN OIL-WATER FILMS REMOVAL

This article describes the process of synthesis of multi-walled carbon nanotubes (MWCNTs) as well as the results of their use as adsorbents for removing the oil contaminants from the surface of water. SEM and TEM analyses were employed to characterize the synthesized MWCNTs. The sorption capacity of MWCNTs for crude oil was 3–4 ml/g, and with an increase in the specific gravity of the petroleum product, this value also increased. Keywords: oil-water films, environmental pollution, multi-walled carbon nanotubes, renewable adsorbents.

Rational Design of Facile and Low‐Cost Construction of Carbon‐Based Dye‐Sensitized Solar Cells using Garcinia Mangostana L. as a Photosensitizer

Research on solar cell devices is not only always related to how to obtain high power conversion efficiency (PCE), but also other factors need to be fully considered, such as the cost and their ecofriendliness. In this present research, a low‐cost and ecofriendly dye‐sensitized solar cell (DSSC) is being developed using a graphite‐based nanocomposite and an unusual plant extract (Garcinia mangostana L.) as the dye photosensitizer. A rational design on how to use graphite as a photoanode and counter electrode (CE) in DSSC is carried out by combining the graphite with ZnO and multiwalled carbon nanotube (MWCNT), respectively. It is observed that graphite acts as a matrix for ZnO and MWCNT to make these nanocomposites have very appropriate optoelectronics and catalytic properties compared to the control sample. Therefore, they could serve as an excellent photoanode and CE, respectively. It is also expected that the anthocyanin absorption in Garcinia mangostana L. dye which is found in the visible light range can efficiently absorb photons, thus supporting the enhancement of photovoltaic performance of the DSSC. The generated voltage (V) and current (I) from light irradiation using commercial lamps are higher compared to halogen lamps, indicating that the obtained DSSC has potential as indoor powered devices. It is believed that our study can shed light on the development of DSSC using low‐cost material graphite as the main component for the realization of low‐cost DSSC devices.