Krypton Gas for High Quality Single Wall Carbon Nanotubes Synthesis by KrF Excimer Laser Ablation

We report for the first time the production of single wall carbon nanotubes (SWCNTs) by KrF excimer laser ablation method under the krypton gas atmosphere. For the ablation experiment 450 mJ energy and 30 Hz repetition rate KrF excimer laser was used, and the target was prepared with the following composition: 0.6% Ni, 0.6% Co, and 98.8% C (atomic percentage). The ablation product was characterized by confocal Raman microspectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The SWCNTs obtained are a mixture of semiconducting and metallic types with narrow diameters distribution of 1.26 to 1.49 nm, are micrometers long, and contain low amount of graphite and amorphous carbon

KrF excimer laser ablation in helium yields the highest amount of SWCNTs over other inert gases

Abstract: The single-wall carbon nanotubes (SWCNTs) were synthesized using the equipment, method and experimental conditions described i

Scanning polarization force microscopy investigation of contact angle and disjoining pressure of glycerol and sulfuric acid on highly oriented pyrolytic graphite and aluminum

For liquid droplets of sub-micrometer dimensions, the study of wetting properties (quantified by contact angle, disjoining pressure, spreading coefficient, etc.) is possible using the relatively new technique known as scanning polarization force microscopy (SPFM). This non-contact scanning probe microscopy technique was successfully implemented in our laboratory in order to study the wetting properties of glycerol and sulfuric acid on the surface of highly oriented pyrolytic graphite (HOPG) and glycerol on aluminum film deposited on mica. An AC polarization bias of 3 V at 3 kHz frequency was applied between a conductive atomic force microscope tip and the substrate. The resulting polarization force was measured with high accuracy, allowing non-contact topography profile measurements of liquid micro- and nanodroplets. The dependence of the contact angle on droplet height was determined in order to calculate the values of the spreading coefficient and the disjoining pressure between the liquid and substrates. The calculated potential energies give disjoining pressure values of ∼0.4 atm for glycerol on HOPG, ∼0.47 atm for glycerol on aluminum and ∼13 atm for H2SO4 on HOPG. In the case of H2SO4 on HOPG the strength of the force appears to be thirty times bigger than that for glycerol on HOPG and aluminum

Influence of the electrochemical treatment on the magnetic properties of nanowires

Abstract: Synthesis of nanomaterials is one of the most researched areas. Nanomaterials are at the core of all modern nano-devices. The reduced size helps electronics to have increased performance, low energy consumption and low heat output. Properties of nanomaterials are mainly related to the involved large surface to volume ratio. Nanomaterials can be fabricated using different methods. One of the intensely used, inexpensive and with high degree of reproducibility is electrochemistry (EC), which can be used either to destroy (corrosion) or to create (thin films, nanoparticles, nanowires (NWs), etc.) materials. In this paper we focus on the effect of the electrochemical treatment (EchT) on the structural and magnetic properties of nanowires. Ni NWs were synthesized and analyzed by SQUID to study the magnetic properties induced by the EchT of the Au substrate. Ni NWs were synthesized in a gold-coated PCTE membrane using template synthesis. The EchT induced structural modifications of the Au substrate and further modifications of NWs magnetism. AFM image of the Au plated PCTE template SEM image of Ni Nanowire