E.F. Antunes

Monolayer formation of human osteoblastic cells on vertically aligned multiwalled carbon nanotube scaffolds

Monolayer formation of SaOS‐2 (human osteoblast‐like cells) was observed on VACNT (vertically aligned multiwalled carbon nanotubes) scaffolds without purification or functionalization. The VACNT were produced by a microwave plasma chemical vapour deposition on titanium surfaces with nickel or iron as catalyst. Cell viability and morphology studies were evaluated by LDH (lactate dehydrogenase) release assay and SEM (scanning electron microscopy), respectively. The non‐toxicity and the flat spreading with monolayer formation of the SaOs‐2 on VACNT scaffolds surface indicate that they can be used for biomedical applications.

Vertically Aligned Carbon Nanotubes/Carbon Fiber Composites for Electrochemical Applications

Carbon fibers have been studied for electrochemical applications. Recently, carbon nanotubes present a wide potential uses in electric, mechanic, electrochemical and materials science field. At present study, vertically aligned carbon nanotubes were produced over carbon fibers. The process occurs catalytically by chemical vapor deposition (CVD) using mixture with camphor and ferrocene. After that, the VACNT/CF composite are treated by oxygen plasma for oxygen functionalization. Prior the electrochemical analysis, CNT/Carbon fibers are treated by hydrochloric acid to remove residual catalyst. The electrodes were tested in a usual electrolyte (with H2SO4 0.5M) in a conventional electrochemical cell. The specific capacitance was tested in a separate device. The configuration of carbon fibers and VACNT presents a high potential application for electro analytical application and energy storage.

Covering Steel Surface with Carbon Black by CO2 Laser

This study investigate the laser surface hardening in tool steel, avoiding the high reflectivity of the metal to the CO2 radiation by covering the surface sample with black carbon. Hardening process using graphite was effective in many works in the word, although, the particles size of graphite powder was in the range of some micrometers. In order to reduce the particle size, the carbon black was used in the laser thermal treatment of 4340 steel. The microhardness change to 850HV, compared to the substrate of 250HV and the friction coefficient ranged 0.2 and 0.3, because of the covered surface by carbon black. These thin coating of carbon black reduced the wear rate near to a hundred in comparison to the surface without carbon coating.

Electric Double Layer Capacitor of Multiwall Carbon Nanotubes under Different Degree of Acid Oxidations

Carbon nanotubes (CNT) are a material with unique properties (mechanical, electrical, electrochemical, etc) allied with low density and high specific area. The present paper studied the electrochemical properties of carbon nanotubes growth by Chemical Vapor Depostion (CVD) technique. The samples were characterized by SEM, Raman Spectroscopy and the double layer capacitance of the powders was evaluated in a Teflon capacitor system with a Ag/AgCl (3M) as reference electrode. The catalyst remotion is provided in Hydrochloric acid washing and the wet oxidative treatments promotes the CNT oxidation and increase the pseudocapacitive response.