Effect of encapsulation of fullerene in semiconducting zigzagcarbon nanotubes on optical and thermoelectric properties

We study the optical and thermoelectric properties of carbon nanotubes (CNTs) with encapsulated C60 fullerene molecules. Using ab-initio methods, we calculate optical and thermoelectric paramters for CNT with fullerenes periodically located inside the nanotube at different distances from each other. Dependencies of these parameters on fullerene concentration and diameter of CNT are analyzed.

Dielectric properties of Shell oil transformer oil with impurities of carbon nanotubes and fullerene C60

At the temperature 293 K, the influence of two types of nanoimpurities (carbon multiwall nanotubes and C60 fullerene) both separately and together on the dielectric properties of Shell oil transformer oil has been studied. It has been shown that these impurities do not significantly effect on the value of the dielectric permittivity of Shell oil, but more significantly increase its conductivity. It has been found that in the presence of nanotubes inside Shell oil, the dependence of its electrical conductivity on the fullerene concentration is nonmonotonic. The samples with the fullerene concentration 100 ppm have the highest conductivity. At the fullerene concentration 300 ppm, the conductivity of Shell oil with the impurities of carbon nanotube and C60 fullerene becomes almost equal to the electrical conductivity of Shell oil only with the impurities of carbon nanotubes. It has been suggested that C60 fullerene can be used to reduce the electrical conductivity of Shell oil with magnetic nanoparticles required to increase the cooling efficiency of transformers under the action of their own magnetic field.

Study on Dispersion Stability and Friction Characteristics of C60 Nanomicrosphere Lubricating Additives for Improving Cutting Conditions in Manufacturing Process

Antifriction lubrication is an important research hotspot in the manufacturing field. A high-performance lubricating additive is of great significance for condition monitoring in the metal cutting process system. To improve cutting conditions in manufacturing process, we study the dispersion stability and tribological properties of fullerene nanoparticles in HM32 antiwear lubricating fluid. Fullerene nanoparticles are fully integrated into HM32 antiwear lubricating fluid by electromagnetic stirring and ultrasonic oscillation. The dispersion stability of fullerene nanoparticles in HM32 antiwear lubricating fluid was comprehensively studied by microscope scanning experiment, static sedimentation experiment, and absorption experiment. The four-ball friction experiment was operated to investigate the extreme pressure property and tribological property of lubricating fluids with fullerene concentration ranging from 100 ppm to 1000 ppm. The results show that fullerene nanoparticle can significantly improve the extreme pressure property and wear resistance of HM32 basic lubricating fluid. Meanwhile, we found that an excessively high concentration of fullerene nanoparticles will increase the friction and wear of the four-ball friction pair. The best concentration of fullerene nanoparticles is 200 ppm. When the fullerene concentration reaches 200 ppm, the maximum nonsintering load is significantly increased, and the friction coefficient and the steel ball wear scar diameter are significantly reduced.

Elucidating the mechanism of cellular uptake of fullerene nanoparticles

Understanding the molecular interactions between biological cells and engineered nanoparticles is a key to evaluating potential toxicities to humans and the environment. This study developed a method to determine the mechanisms by which fullerene aggregates are distributed into a representative cell line, human intestinal Caco-2 cells. First, we determined that the presence of fetal bovine serum (FBS) in the cell culture media changes the particle characteristics and inhibits particle adsorptions onto cell surfaces. Second, significantly lower amounts of fullerene were internalized at 4°C, a temperature at which active transport mechanisms are effectively impeded, than at 37°C. Third, metabolic inhibitors of active transport and a microtubule transport inhibitor decreased fullerene uptake at 37°C. Fourth, cellular uptake of fullerene increased with increasing fullerene concentration, suggesting that passive diffusion into lipid membranes contributed to uptake over the broad concentration range used in this study. Together, these results indicate fullerene transport into cells occurs via two mechanisms: passive diffusion across the lipid bilayer and active transport including microtubule involved endocytosis. The results also suggest that simple physical-chemical partitioning models do not fully describe fullerene uptake, and instead, active transport models are also required to estimate the cellular uptake and toxicity of fullerene.

Evaluation of tribological characteristics of liquid lubricants with fullerene additives

The paper presents experimental studies of the tribological characteristics of liquid lubricants of various viscosity classes and various groups of operation when using fullerene additives. Tribological characteristics were evaluated on a four-ball friction machine according to GOST 9490. Assessment was subject to: wear rate and critical load, which characterize the anti-wear properties of the lubricant, as well as welding load and bully index, which characterize an anti-bully properties of the material. It is shown that the improvement of the wear index for all oils begins with the concentration 0,2 % masses, fullerenes in the lubricant and does not exceed the values 11,1 … 15 %. At a fullerene concentration less than 0,2 % masses, no positive effect is observed. Positive effect 11,8 … 17,4 % characteristic of the indicator – critical load that characterizes the range of performance of anti-wear additives. At the same time, an increase in the critical load begins with concentration 0,1 % masses, fullerenes in a lubricant and manifests itself most effectively at a concentration 0,2 % masses. Changes in the magnitude of the welding load during the experiments were not recorded, this allows us to conclude, that the addition of a finely dispersed fullerene powder in a liquid lubricant does not improve anti-bully properties, but is only an anti-wear additive. It is shown that the way to improve the tribological properties of lubricants by introducing a finely dispersed powder of fullerenes in base technical oils is ineffective. It is necessary to develop other, more technological methods and methods for introducing fullerene additives into technical lubricants.

LIQUID CRYSTAL MATERIALS ORIENTATION USING NEW APPROACH

It is well known that the liquid crystal (LC) mesophase is actively used in display technique and biomedicine devices. Unfortunately, the switching time of the devices based on the LCs is not fast enough; thus, it is very important to find novel perspective ways to obtain the good switching time of the LC dipoles used in these devices. Initial orientation of the LC molecules influences the dynamic parameters, for example, the switch-on and switch-off characteristics and the diffraction efficiency of the final devices. Among the different methods and approaches to find the optimized orientation of the inertial LC molecules a nanotechnology approach has shown the best results. This approach allows increasing the transparency, to decrease the resistivity and the number of the functional layers in the sandwich LC structures. Thus, it results in a decrease in the applied bias voltage. The effect is based on the fact that the ITO coating can be considered as the conducting layer and as the orienting (alignment) layer simultaneously. In the current paper, we continue our steps in the direction to find the best way of the LC molecules orientation. It is proposed to consider the LC media sensitization process as the method to change the surface relief when this relief is prepared from the polymeric orienting materials doped with the carbon nano-objects. Based on the solid fullerene-doped polyimide thin films and other organics it can be shown that the content of the fullerenes influences the wetting angle significantly. The fullerene concentration is correlated with the different surface relief view applied in the aligning of the LC molecules. The switching of the LC can be improved; furthermore the novel relief depended on the fullerene content can be used for the optical limiting of the laser irradiation.

Synthesis, electrochemical and complexation studies of Zn(II) aryloxyporphyrins with fullerene C60

A new series of aryloxyporphyrins bearing benzyl and naphthyl substituents viz., ZnTBPP (1), ZnTNPP (2) and ZnONPP (3) has been synthesized and characterized by UV-vis, fluorescence and 1H NMR spectroscopic techniques and mass spectrometry. 1–3 have been utilized as donors to interact with fullerene (C[Formula: see text] acceptor to form 1:1 complex in toluene at 298 K. The subsequent investigation into quenching measurements with concomitant increase in fullerene concentration revealed effective quenching constants. The calculated association constants were in the order of 103 M[Formula: see text]. However, ZnTNPP (2) exhibited higher binding constant as compared to other analogs due to effective [Formula: see text]–[Formula: see text] interactions. ZnONPP (3) exhibited 3.4 times lower association constant than ZnTNPP (2) due to steric hindrance offered by meso-(3,5-dinapthyloxyphenyl) groups. The geometric and electronic structure of Zn(II) porphyrin-fullerene dyad was probed by DFT calculations which suggested the possibility of charge transfer from meso-aryloxyporphyrin core to fullerene C[Formula: see text].