Fullerene Concentration Research Articles

Analysis of impulse withstand voltage of ester-based nanofluids

Ester-based nanofluids constitute an effective ecological alternative to petroleum-derived dielectric fluids for electrical engineering industry. Pulse induced dielectric breakdown is a key cause of power device failure. In this paper, we deal with the lightning impulse breakdown voltage (LI BDV) in natural and synthetic ester-based (NE and SE) nanofluids with various concentrations of magnetite (Fe3O4) and fullerene (C60) nanoparticles. The nanofluids show a decrement in positive polarity LI+ BDV as compared with the base ester. Negative polarity LI- BDV in the nanofluids is similar to that of base oils. Weibull statistical distributions are applied to analyse the results at different cumulative probabilities of 1 %, 10 %, and 50 %. Natural ester with C60 nanoparticles shows higher positive LI+ BDV values at a low probability level, while the negative LI- BDV reaches higher values at higher probability levels. The decreased LI BDV in NE and SE due to the magnetite nanoparticles are attributed to the nanoparticle clustering and percolation. The tendency of C60 nanoparticles to enhance the LI BDV in NE but not in SE is interpreted in the view of the nanoparticle concentration and oil's viscosity effect on the streamer branching and propagation.

Dielectric relaxation spectroscopy of hybrid insulating nanofluids in time, distribution, and frequency domain

Improving the dielectric properties of insulating liquids belongs to the modern motivation to optimize the operation of high-voltage devices. Hybrid nanofluids can provide the mentioned improvement, and thus, it is necessary to reveal their hidden potential. This study investigates hybrid nanofluids with different concentrations of magnetite and fullerene nanoparticles, a separate fullerene and magnetic nanofluid, and a base carrier fluid based on gas-to-liquid technology. The investigated samples are subjected to dielectric relaxation spectroscopy analysis at three applied electric field intensities in the time, distribution, and frequency domain. The lack of information about the studied parameters of the mentioned nanofluids is another reason for our experimental measurements. A significant dispersion of the charging current characteristics of nanofluids with magnetic nanoparticles is observed. At lower electric field intensities, the increasing fullerene concentration of the hybrid nanofluids reduces the charging currents up to a charging time of 200 s. Magnetic nanofluid shows the highest values of conductivity currents. Experiments show that the suspension of fullerene in the base oil causes a higher charging current and a more pronounced relaxation response than pure base oil. Significant relaxation information in the low-frequency band is detected from the distribution spectra. At higher electric field intensities in the low-frequency spectrum, the relaxation peaks decrease when the concentration of fullerene in hybrid nanofluids increases. The distribution area shows the effect of higher polarizability of magnetite nanoparticles. Compared to lower electric field intensities, at the value of 333.3 kV/m, several polarization processes are captured in the entire frequency spectrum. The frequency-dependent complex permittivity confirms the findings from the time and distribution domains. Comparing the distribution domain with the frequency domain shows higher sensitivity and accuracy in capturing relaxation processes in the distribution domain.

C60 fullerene nanoparticles permeability through the model lipid envelope of coronavirus and their anticoronavirus effect in the in ovo system

Background: An urgent problem of modern biomedicine is the search for potential ways to reduce the spread of coronavirus infections in human and animal populations and eliminate the impact of coronavirus on their bodies. Aim of the work was to determine the structural organization of C60 fullerenes in a model cell medium, to assess their potential ability to penetrate the model lipid envelope of a coronavirus, thus destroying its integrity, as well as the effectiveness of the anticoronavirus action in the in ovo system. Methods: The research was conducted using the Gromacs 2020 software package and the Charmm36 force field. The CHARMM-GUI web resource was used to construct the lipid envelope of a coronavirus. Virological and toxicological methods were used in the in ovo experiments. Results: It is shown that at the initial stages of molecular dynamics C60 fullerene forms small nanoclusters in the amount of 7–16 molecules, which is affected by the initial concentration of C60 fullerene in a model cell medium. At the same time, the shape of nanostructures for the number of molecules over 16 may differ from the correct spherical shape. It was established that C60 fullerene and its nanoclusters are able to penetrate inside the lipid envelope of a coronavirus. In particular, a single C60 molecule can migrate, completely embed itself in the lipid envelope, or move within it. It was found that C60 fullerene aqueous solution, at the maximum permissible concentration (MPC) of 30 μg/embryo, reduces the infectious activity of the chicken infectious bronchitis (CIB) coronavirus when it is used 1, 2 and 4 h after the infection of a sensitive biological system with a coronavirus. Conclusions: It is shown that aggregation of C60 fullerene in a model cell medium can occur in different ways: either before penetration into the lipid envelope of a coronavirus, or inside it. C60 fullerenes, both individually and as part of nanoclusters, are able to form pores in the envelope of a coronavirus, destroying its integrity, which possibly leads to disruption of the corresponding stages of its replication cycle and attachment to cell receptors. It was established that C60 fullerene aqueous solution, when used in the MPC value, shows antiviral activity against the CIB coronavirus in its early stages of interaction with the cell (1–4 h).

Silver-Matrix Composite with Fullerene Soot Nanoparticles Produced by Electrodeposition

The presented work demonstrates the capability of obtaining composite powder, silver-fullerene soot, by the electrolytic deposition of silver from an aqueous solution of silver nitrate. The morphology of particles was studied as a function of fullerene soot concentration and current density. The microstructure of compact materials obtained by hot pressing was investigated. The hardness of the compact material increased up to 30% and the same corrosion properties relative to pure silver were obtained using a similar technology.

EVALUATION OF THE POTENTIAL NEUROACTIVITY IN THE BRAIN NERVE TERMINALS OF THE C60 FULLERENE PLANETARY DUST COMPONENT

A study of the infrared spectrum of the environment of the planetary nebula Tc 1 revealed the radiation of cold and neutral fullerenes C60 and C70. The results of the analysis of infrared spectra obtained using the Hubble space telescope conclusively proved the existence of C60+ fullerene in the interstellar medium. These large carbon-containing molecules can form and exist in the interstellar medium and are candidates to explain many diffuse interstellar absorption bands. In this study, the potential neuroactivity of the C60 fullerene as a planetary dust component was assessed in the isolated rat brain nerve terminals. It was shown that C60 fullerene in the unirradiated state at concentrations of 0.05—0.25 mg/ml did not change the extracellular levels of excitatory neurotransmitter L-[ 14C]glutamate and inhibitory neurotransmitter [ 3H]GABA in the preparations of rat brain nerve terminals. An increase in fullerene C60 concentrations up to 0.5 and 1.00 mg/ml was accompanied by an increase in the extracellular levels of L-[ 14C]glutamate and [3 H]GABA in the preparations of nerve terminals. Therefore, fullerene C60 did not cause signs of acute neurotoxicity in the brain nerve terminals within the concentration range of 0.05—0.25 mg/ml. However, given that C60 undergoes photooxidation, it can be expected that it may acquire neurotoxic properties in situ.

Behavior of C70 Fullerene in a Binary Mixture of Xylene and Tetrahydrofuran

The self-organization properties of C70 fullerene molecules in a xylene/tetrahydrofuran binary mixture were studied for the first time by optical absorption, refractometry, and dynamic light scattering. A correlation has been established between the change in the refractive index of the C70/xylene/tetrahydrofuran solution and the degree of self-organization of C70 molecules in the medium at various concentrations and storage periods of the solution. It is shown that the features of the optical absorption spectrum of C70/xylene/tetrahydrofuran at a fixed low concentration of fullerene are sensitive to its storage time. It was determined that the beginning time of the formation of C70 nanoclusters and their final size depend on the degree of concentration of fullerene and the time spent keeping the solution. The observed nature of the C70 fullerene solution in a binary mixture may help to elucidate its mechanism of self-organization in the future.

Self-Assembly of Uniaxial Fullerene Supramolecules Aligned within Carbon Nanotube Fibers.

The conductivity and strength of carbon nanotube (CNT) wires currently rival those of existing engineering materials; fullerene-based materials have not progressed similarly, despite their exciting transport properties such as superconductivity. This communication reveals a new mechanically robust wire of mutually aligned fullerene supramolecules self-assembled between CNT bundles, where the fullerene supramolecular internal crystal structure and outer surface are aligned and dispersed with the CNT bundles. The crystallinity, crystal dimensions, and other structural features of the fullerene supramolecular network are impacted by a number of important production processes such as fullerene concentration and postprocess annealing. The crystal spacing of the CNTs and fullerenes is not altered, suggesting that they are not exerting significant internal pressure on each other. In low concentrations, the addition of networked fullerenes makes the CNT wire mechanically stronger. More importantly, novel mutually aligned and networked fullerene supramolecules are now in a bulk self-supporting architecture.

Features of C60 fullerene in the toluene-hexane solvent system

he behaviors of self-aggregation of C60 molecules in solution of C60/toluene/hexane were studied by the methods of refractometry, ultraviolet-visible spectroscopy, dynamic light scattering (DLS) and electron microscopy. It has been experimentally shown that with a slight increase in both the concentration of C60 fullerene and the volume fraction of toluene in a C60/toluene/hexane solution, a change in the refractive index of the medium and in the behavior of the optical spectrum is observed. An increase in the content of toluene in the solution manifests both a positive solvatochromic effect and a hyperchromic effect in the intense absorption band at 328.8 nm. At the same time, it was established by DLS that with an increase in the mole fraction of toluene in the C60/toluene/hexane system, the size of nanoclusters synthesized inside the solution decreases. After evaporation of hexane/toluene from fullerene solution droplets transferred to a heated substrate (up to 30°C), filamentary crystalline nanostructures based on C60 fullerene are formed on the substrate surface.

Method development for the LC-MS/MS determination of C60 and C70 fullerenes and their functionalized derivatives in airborne particulate matter, settled dust and soot

Fullerenes are organic contaminants of growing concern due to their increasing use for industrial purposes, in addition to their emission by natural and anthropogenic combustion sources.Their analysis is made tricky by their unique chemical structure and their acute hydrophobicity. Thus, analytical developments are required for further environmental evaluation of their occurrence. This article presents such a development for the analysis of C60 and C70 fullerenes together with three of their functionalized derivatives in airborne particulate matter, settled dust and soot from diesel exhaust.Pressurized Liquid Extraction was performed with toluene and acetonitrile as extraction solvents, and gave mean extraction recoveries from 75% to 95% for the five fullerenes investigated.Liquid Chromatography was optimized in terms of stationary phase and mobile phase to obtain a good separation of the compounds. Optimal separation of the compounds by liquid chromatography were obtained using a C18 stationary phase and a mixture of toluene - acetonitrile as mobile phase in gradient mode.The mass spectrometry detection method was also optimized with a comparison of three ionization sources: Electrospray ionization (ESI), Atmospheric Pressure Chemical Ionization (APCI) and Atmospheric Pressure PhotoIonization (APPI). APPI gave the most sensitive and repeatable detection with instrumental limits of quantification (LOQ) down to 10 pg injected. MS/MS was used in pseudo-MRM mode to enhance signal intensity.The optimized LC-APPI-MS/MS method was then validated and applied to indoor PM10 and household dust samples, and to a Diesel Particulate Matter Reference Material. None of these samples showed concentrations of fullerenes above the method quantification limits.

High photothermal conversion efficiency for semiconducting polymer/fullerene nanoparticles and its correlation with photoluminescence quenching

The fullerene concentration in semiconducting polymer nanoparticles (SPNs) decreases the photoluminescent (PL) and increases the photothermal (PT) effects due to enhanced non-radioative recombination of charge transfer (CT) excitons.

Synthetic and natural ester-based nanofluids with fullerene and magnetite nanoparticles – An experimental AC breakdown voltage study

Ester-based electrical insulating liquids constitute an attractive alternative to widely used mineral oils, especially due to their ecological benefits. In this study, we present an experimental comparison of AC breakdown voltage (BDV) in both natural and synthetic ester-based nanofluids with various concentrations of fullerene (C60) and magnetite (Fe3O4) nanoparticles. The BDV measurement was conducted with an AC voltage rise rate of 2 kV/s according IEC 60156 standard. While the suspensions of magnetite nanoparticles exhibited increased AC BDV for all samples tested, the fullerene-based nanofluids exhibited the enhanced AC BDV only for two among six nanoparticle concentrations. Accordingly, we present a comparative view of the electrical breakdown development using statistical descriptors. This study uses Weibull and normal distributions for statistical analysis to estimate AC breakdown voltage at different cumulative probability levels 1 %, 10 %, and 50 %. The parameters of theoretical distributions are fitted to the experimental data. Subsequently, statistical test of conformity to the distributions, and their skewness and kurtosis are analysed. The analysis reveals that AC BDV of nanofluids increases with the increasing cumulative probability more than those of pure esters. It is shown that the addition of fullerene nanoparticles tends to reduce AC BDV in the natural ester but not in the synthetic ester. The presence of magnetic nanoparticles in both esters yielded an enhancement of the AC BDV but in a different measure.

ВЛИЯНИЕ СМАЗОЧНЫХ КОМПОЗИЦИЙ С СОДЕРЖАНИЕМ ФУЛЛЕРЕНОВ НА ПРОЦЕСС ОСАДКИ ЗАГОТОВКИ

The study objective is a comparative analysis of the effect of nano-additives in engine oil on reducing the friction factor during upsetting. The task to which the paper is devoted is to obtain lubricants with different concentrations of fullerenes (C60) and analyze comparative tests of lubricant compositions. Research methods: lubricating compositions are obtained by mixing on an ultrasonic dispersant in the laboratory of friction units for extreme conditions of IMASH RAS; experimental studies are carried out at MIREA – Russian Technological University using the laboratory complex "Metal Working Process. Computerized CNC Press" which implements upsetting. Novelty of the work: for the first time, the effect of different concentrations of fullerenes (C60) on the upsetting is studied. Study results: experiments are performed on the workpiece upsetting; the dependences of the force on the workpiece movement for the tested lubricants are obtained. The main conclusion of the study is that engine oil with the introduction of fullerenes reduces the resistance to deformation of the workpiece and the friction factor

Investigation of C60/NMP and C60/NMP/xylene solutions by absorption spectroscopy and dynamic light scattering

The behavior of intermolecular interactions in fresh and aged solutions of fullerene C60 in neat N-methyl-2-pyrrolidone (NMP), as well as in NMP/xylene mixed solvents, were studied by the methods of ultraviolet-visible spectroscopy and dynamic light scattering (DLS). It has been experimentally shown that the aging of the C60/NMP solution leads to the disappearance of the characteristic maximum of molecular absorption at ∼330 nm with smoothing, as well as to an increase in the optical absorption intensity. The latter depend on the formation of “C60- NMP”complexes, as well as on the transition of fullerene molecules to the nanocluster state. Increasing the xylene content in the C60/NMP leads to significant changes in charge transfer between solute and solvent (“C60-NMP”, “C60-C60”) at a fixed concentration of fullerene. The latter leads to the reorganization of nanoparticles, which proceeds with the destruction of molecular complexes. In this case, using the DLS method, it was found that the geometric dimensions of the synthesized C60 nanoclusters decrease.

Dielectric response of a hybrid nanofluid containing fullerene C60 and iron oxide nanoparticles

Dielectric nanofluids based on transformer oil and magnetic nanoparticles are attractive due to the controllability of their physical properties by magnetic fields. Fullerene-based nanofluids often exhibit superior dielectric performance. In this study, we combine both iron oxide and fullerene nanoparticles into a transformer oil-based hybrid nanofluid. Using the method of dielectric relaxation spectroscopy, we examine the dielectric response of six samples with different fullerene-magnetic nanoparticle concentrations in the frequency range 0.1 mHz – 10 kHz. The study reveals that the dielectric response of magnetic nanoparticles dominates the dielectric spectrum of the hybrid nanofluids. The spectrum is characterized by a low-frequency Debye-like relaxation process associated with the interfacial polarization mechanism. The process is analyzed in the complex permittivity, electric modulus, and impedance plane. A logarithmic increase in relaxation times is observed with a linearly increasing concentration of fullerenes. The hybrid nanofluid with the highest fullerene concentration of 0.03 %w/V shows the lowest dielectric losses at the mains frequencies. When magnetic nanoparticles are absent, the dielectric spectrum of the fullerene nanofluid resembles that of the pure transformer oil. Around the mains frequencies, the dielectric losses of nanofluid containing only 0.01 %w/V of fullerene have been found lower than those of pure transformer oil. The complex impedance analysis revealed that the electrical conductivity of the hybrid nanofluids has a purely unidirectional character.

Effect of the Interface on the Compressibility of Substances with Spherical Nano-Inhomogeneities on the Example of Al/C60.

The paper examines the compressibility of media with nano-inhomogeneities using the example of an aluminum melt and C60 fullerenes immersed in it. The results of molecular dynamics simulations indicate a significant effect of the interface on the effective compressibility of a heterogeneous medium. It is found that the application of the rule of mixture for the Al/C60 system results in an incorrect qualitative picture of the dependence of compressibility on the concentration of fullerenes. To explain this effect, an analytical model is proposed that takes into account the reduction in distances between atoms of different components during compression. The model makes it possible to estimate the effective mechanical characteristics of a liquid with nano-inhomogeneities within the framework of the mechanical approach, and correctly predicts the nature of the change in the dependence of compressibility on concentration.

Experimental and theoretical investigations on fullerene (C60) induced compact CH3NH3PbI3 perovskite thin films

In the present work, pure and Fullerene (C60)-doped methyl ammonium lead halide (CH3NH3PbI3) perovskite thin films were prepared on glass substrates by spin coating method at different concentrations of fullerene (C60).The structural, morphological, and optical characteristics of as-prepared thin films were analysed using experimental and computational methods. The X-ray diffraction studies and their Reitveld refinement analysis of the samples confirms that all deposited perovskite thin films have tetragonal structure and are highly oriented along the (110) plane. The morphology of the perovskite films was investigated by field emission scanning electron microscope (FE-SEM). The elemental composition of perovskite thin films was confirmed by Energy Dispersive X-rays Analysis (EDAX). The addition of fullerene (C60) resulted in the increase of grain size sand a more compact surface development of the perovskite thin films with fewer flaws as compared with perovskite thin films without (C60) was evaluated. Also, geometrical, electronic and optical properties were studied by using the first principles DFT computational method. Optical properties have been studied experimentally and verified computationally. All the perovskite thin film samples exhibit direct band-gap which is suitable for solar cells applications.

Self-Assembly in water of C60 fullerene into isotropic nanoparticles or nanoplatelets mediated by a cationic amphiphilic polymer

HypothesisTo disperse high concentration of C60 fullerene in water, we propose to use an emulsification-evaporation process in the presence of an amphiphilic polymer whose chemical structure has been chosen for inducing specific interaction with fullerene The viscosity enhancement provided by self-assembly of the amphiphilic polymers in water should result in high stability of the suspensions. The organic solvent has also to been chosen so as to maximize the initial fullerene concentration. ExperimentsThe concentrations of polymer and fullerene, the solvent type and the volume fraction of the organic phase have been varied. Their influence on the concentration of the fullerene dispersions and on the size and shape of the resulting nanoparticles have been investigated by UV–Visible spectroscopy, light scattering and cryo-transmission electron microscopy experiments. FindingsThe resulting nanoparticles consist of aggregates of C60 fullerene stabilized by the cationic polymer with morphologies/sizes tunable through fullerene and polymer concentration. At high fullerene concentration, nanoplatelets are obtained that consist in thin 2D nanocrystals. Their suspensions are very stable with time due to the viscosity of the dispersing aqueous medium. The concentration of fullerene nanoparticles dispersed in water is as high as 8 g/L which corresponds to an upper limit that has never been reached so far.

Fullerenes' Interactions with Plasma Membranes: Insight from the MD Simulations.

Understanding the interactions between carbon nanoparticles (CNPs) and biological membranes is critically important for applications of CNPs in biomedicine and toxicology. Due to the complexity and diversity of the systems, most molecular simulation studies have focused on the interactions of CNPs and single component bilayers. In this work, we performed coarse-grained molecular dynamic (CGMD) simulations to investigate the behaviors of fullerenes in the presence of multiple lipid components in the plasma membranes with varying fullerene concentrations. Our results reveal that fullerenes can spontaneously penetrate the plasma membrane. Interestingly, fullerenes prefer to locate themselves in the region of the highly unsaturated lipids that are enriched in the inner leaflet of the plasma membrane. This causes fullerene aggregation even at low concentrations. When increasing fullerene concentrations, the fullerene clusters grow, and budding may emerge at the inner leaflet of the plasma membrane. Our findings suggest by tuning the lipid composition, fullerenes can be loaded deeply inside the plasma membrane, which can be useful for designing drug carrier liposomes. Moreover, the mechanisms of how fullerenes perturb multicomponent cell membranes and how they directly enter the cell are proposed. These insights can help to determine fullerene toxicity in living cells.

The biphasic responses of nanomaterial fullerene on stomatal movement, water status, chlorophyll a fluorescence transient, radical scavenging system and aquaporin-related gene expression in Zea mays under cobalt stress

Nanomaterial fullerene (FLN) has different responses called the hormesis effect against stress conditions. The favorable/adverse impacts of hormesis on crop quality and productivity are under development in agrotechnology. In this study, the effect of FLN administration (100-250-500mg L−1 for FLN1-2-3, respectively) on growth, water management, gas exchange, chlorophyll fluorescence kinetics and cobalt (Co)-induced oxidative stress in Zea mays was investigated. The negative alterations in relative growth rate (RGR), water status (relative water content, osmotic potential and proline content) and gas exchange/stomatal regulation were removed by FLNs. FLNs were shown to protect photosynthetic apparatus and preserve the photochemistry of photosystems (PSI–PSII) in photosynthesis, chlorophyll fluorescence transients and energy flux damaged under Co stress. The maize leaves exposed to Co stress exhibited a high accumulation of hydrogen peroxide (H2O2) due to insufficient scavenging activity, which was confirmed by reactive oxygen species (ROS)-specific fluorescence visualization in guard cells. FLN regulated the gene expression of ribulose-1,5-bisphosphate carboxylase large subunit (rbcL), nodulin 26-like intrinsic protein1-1 (NIP1-1) and tonoplast intrinsic protein2-1 (TIP2-1) under stress. After stress exposure, FLNs successfully eliminated H2O2 content produced by superoxide dismutase (SOD) activity of catalase (CAT) and peroxidase (POX). The ascorbate (AsA) regeneration was achieved in all FLN applications together with Co stress through the elevated monodehydroascorbate reductase (MDHAR, under all FLNs) and dehydroascorbate reductase (DHAR, only FLN1). However, dose-dependent FLNs (FLN1-2) provided the induced pool of glutathione (GSH) and GSH redox state. Hydroponically applied FLNs removed the restrictions on metabolism and biological process induced by lipid peroxidation (TBARS content) and excessive ROS production. Considering all data, the modulation of treatment practices in terms of FLN concentrations and forms of its application will provide a unique platform for improving agricultural productivity and stress resistance in crops. The current study provided the first findings on the chlorophyll a fluorescence transient and localization of ROS in guard cells of Zea mays exposed to FLN and Co stress.

Термодеструкция полиметилметакрилата и его композита с фуллереном C-=SUB=-60-=/SUB=- после ультрафиолетового облучения

The analysis of the ultraviolet induced transformation of the thermal decomposition spectra of the monomer of the submicrometer layers of polymethylmethacrylate and its composite with fullerene C60 for different fullerene concentrations and irradiation doses has been carried out. Formation of the new decomposition stages in the spectra has been interpreted by the binding between C60 and side ester groups of polymethylmethacrylate.