Production and Properties of Carbon Nanotube/Cellulose Composite Paper

Multiwalled carbon nanotube/cellulose composite papers have been prepared by mixing the cellulose with MWNT/gelatin solution and drying at room temperature. The CNTs form an interconnected network on the cellulose paper and as a result CNT paper sheet exhibits enhanced electrical properties and thermal stabilities. It is found that both sides of CNT paper sheet have the uniform electrical conductivities. The sheet exhibits strong microwave absorption in the microwave range of 10.5 GHz. The CNT/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. This work provides a novel and simple pathway to make CNT/cellulose sheet as multifunctional biomaterials for electronic, magnetic, semiconducting, and biotechnological applications

Safer Production of Water Dispersible Carbon Nanotubes and Nanotube/Cotton Composite Materials

Water-dispersible carbon nanotubes (WD-CNTs) have great importance in the fields of biotechnology, microelectronics, and composite materials. Sidewall functionalization is a popular method of enhancing their dispersibility in a solvent, which is usually achieved by strong acidic treatment. But, treatment under such harsh conditions deviates from green chemistry and degrades the structure and valuable properties of CNTs. Alternative safer and easier plasma method is discussed to produce functionalized CNTs (f-CNTs). The f-CNTs remain dispersed in water for more than 1 month owing to the attachment of a large number of carboxyl groups onto their surfaces. The WD-CNTs are applied to produce conductive cotton textile for the next generation textile technologies. Nonconducting cotton textile becomes electroconductive by repeatedly dipping into the f-CNT-ink and drying in air. The f-CNTs uniformly and strongly cover the individual cotton fibers. After several cycle of dipping into the f-CNT-ink, the textile becomes conductive enough to be used as wire in lighting up an LED. As a demonstration of practical use, the textile is shown as a conductive textile heater, where the textile can produce uniformly up to ca. 80°C within ca. 5 min by applying an electric power of ca. 0.1 W/cm2

Production of Water Dispersible Carbon Nanotubes and Nanotube/Cellulose Composite

Polymer wrapping methods have been used to disperse carbon nanotube (CNT) by using gelatin, an environment-friendly and easily decomposable biopolymer. The amino acid chain of gelatin becomes immobilized by the physical adsorption in the side wall of the CNTs through hydrophobic-hydrophobic interaction and results in the untangling of the CNT bundles. The dispersed solution remains stable for more than a month. Furthermore, this technique does not affect the physical properties of CNTs while enabling their dispersion in aqueous solutions. In addition, gelatin can be easily removed from the nanotubes after the dispersion of nanotubes by heating in water and filtration. Gelatin-dispersed CNTs are homogeneously mixed with the cellulose suspension and dried at room temperature to produce CNT/cellulose composite paper sheet. Adding multiwalled carbon nanotubes (MWNTs) in composite improves the mechanical, thermal, and electrical properties of cellulose. SEM investigation confirms the homogeneous distribution of MWNTs in the cellulose, which can be attributed to the improvement of its characteristics. Both sides of the CNT/cellulose sheet show uniform electrical conductivity, which is enhanced by increasing the MWNTs’ content. IR image of the sheet clearly shows the temperature homogeneity of the surface. Thermal stability and the flame retardancy of the sheet are also found to be improved. The sheet has also strong absorbing of electromagnetic waves, which make them important for microwave technology applications

Water-Dispersible Multiwalled Carbon Nanotubes Obtained from Citric-Acid-Assisted Oxygen Plasma Functionalization

A new and safe method has been developed to functionalize multiwalled carbon nanotubes (MWCNTs) with fewer surface defects, which significantly increases their dispersibility in water. MWCNTs are pretreated in pure ethanol by a supersonic homogenizer. Then, the mixture is dried and soaked in weak citric acid solution. Finally, the MWCNTs in the citric acid solution are treated with radio frequency (13.56 MHz) oxygen plasma. As a result, many carboxyl functional groups are attached onto the MWCNT surfaces and stable dispersion of the MWCNTs in water is obtained. The treatment conditions are optimized in this study

Kinetics of Electron-Beam Dispersion of Fullerite C60

Electron-beam dispersion of pressed fullerite C60 targets in vacuum leads to the deposition of thin films containing polymeric forms of C60. The aim of the present report is to analyze physical-chemical processes in the fullerite target during its electron-beam dispersion through the analysis of the kinetics of the radiation temperature of the target surface, the coating growth rate and the density of negative current on the substrate. It was shown that the induction stage of the process is determined by the negative charging and radiation-induced modification and heating of the target. The transitional stage is characterized by nonstationary sublimation of the target material through the pores in the modified surface layer and release of the accumulated negative charge. Stabilization of the process parameters owing to the convection cooling of the target by the sublimation products and the decrease in the pressure inside the microcavities beneath the pores leads to a quasi-stationary stage of target sublimation and deposition of a coating containing polymeric forms of C60.Comment: 13 pages, 6 figure

Thin polymerized C60 coatings deposited in electrostatic field via electron-beam dispersion of fullerite

The aim of the present study is to clarify the charge composition of fullerite C60 electron-beam dispersion (EBD) products and investigate the influence of fullerene ions and electrons on the structure of the deposited coatings by applying an additional electrostatic field to the substrates. It was found that C60 EBD products contain positive fullerene ions and electrons. By using Raman and attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, laser desorption/ionization mass-spectrometry and atomic force microscopy, it was shown that the assistance of the electrons additionally accelerated up to 300 eV results in the formation of a mixture of dumb-bell- and peanut-shaped C60 polymers. The assistance of the positive fullerene ions additionally accelerated up to 300 eV leads to the formation of highly cross-linked random 3D networks of covalently bonded fullerene molecules.Comment: 15 pages, 8 figure

Experimental and Numerical Studies of Heat Convection in the Synthesis of Single-Walled Carbon Nanotubes by Arc Vaporization

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Plasma Science and Technology - Progress in Physical States and Chemical Reactions

In the early twentieth century, Dr. Irving Langmuir actively studied plasma discharge and surface science. Since then, great progress has been made in the development of applications of discharges and plasmas such as discharge lamps, electric tubes, and arc welding. In relation to studies on space physics and controlled nuclear fusion, plasma physics has greatly advanced. Plasma chemistry has also progressed along with its applications in LSI fabrication technology, the chemical vapor deposition of functional films, and the production of nanomaterials. In the twenty-first century, the further development of applications of plasma physics and plasma chemistry is certainly expected. In this book, 18 chapters on the recent progress in plasma science and technology have been written by active specialists worldwide