Papers by Author: Seung Hyun Baik

Abstract: Carbon nanotubes have received considerable attention because of their excellent electrical and mechanical properties. In this study, carbon nanotube - copper nanocomposites with homogeneously dispersed nanotubes within the copper matrix have been fabricated by two different methods; a mechanical mixing process and a molecular-level mixing process, which consists of mixing copper ions with functionalized nanotubes in a solvent. Small punch creep tests showed significantly improved mechanical properties of the nanocomposites. The electrical resistance of the nanocomposites also decreased.

Abstract: The effects of acid treatment methods on the fracture of single walled carbon nanotubes are investigated using gel electrophoresis and Raman spectroscopic techniques. The mechanism of gel electrophoresis is based on the migration of charged particles in an electric field, and the gel matrix acts as a sieve for the analyte. A comparative Raman spectroscopy analysis, performed on the migrated nanotubes in the gel, shows that small diameter tubes are cut shorter by the acid treatments.

Abstract: The tribological performance of ordered mesoporous carbons (CMK-3) as lubricant additives is investigated at ambient temperature. The effects of CMK-3 on the frictional forces, wear amounts and cycles to scuffing are measured using a ball-on-disk tester. It was found that there was little difference in the frictional forces and wear amounts of the oils with and without CMK-3. However, the scuffing time of the oil with CMK-3 was much longer than that of the pure mineral oil in sliding tests. CMK-3 were very effective on maintaining the oil gap and protecting the surfaces in boundary lubricated sliding.

Abstract: We propose to use electrostatic drop-on-demand devices, with precise metering and accurate delivery capabilities, to manipulate single-walled carbon nanotubes suspended in solution. The conductivity of the solution increases significantly by the addition of anionic surfactants and nanotubes, generating favorable conditions for electrostatic ejection. This technique could find applications, combined with chemical functionalization, in the fabrication of carbon nanotube field emission devices as well as electronic circuits. hanseoko@yurim.skku.ac.kr

Abstract: The tribological performance of multi-walled carbon nanotubes (MWNT) in mineral oils is investigated at ambient temperature. The frictional forces, wear amounts and cycles to scuffing of the oils with nanotubes and without those were measured using the ball-on-disk tester. It was found that there were little differences in the frictional forces and wear amounts of two oils. However, the scuffing times of oils with nanotubes were much longer than those of oils without nanotubes in sliding tests. The nanotubes were very effective on maintaining the oil gap and protecting the surfaces in boundary lubricated sliding.