Search

Your search keyword '"Graupner, Raif"' showing total 4 results
Start Over Author "Graupner, Raif"
4 results on '"Graupner, Raif"'

1. Interconnection of Chemically Functionalized Single-Wall Carbon Nanotubes via Molecular Linkers.

Author

Dettlaff-Weglikowska, Urszula, Skakalova, Viera, Graupner, Raif, Ley, Lothar, and Roth, Siegmar

Subjects
NANOTUBES, HIGH pressure chemistry, OXIDATION, CHLORIDES
Abstract

Single wall carbon nanotubes produced by high pressure CO decomposition (HiPco process) were oxidized in air at 350 °C and treated by thionyl chloride to generate acylchloride groups. Subsequent coupling reactions were carried out with different amine molecules to form intertube junctions. Tripropylentetramine, 2,4,6-triaminopirimidine and 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole have been chosen as a molecular linker. The reaction products were characterized by XPS and Raman spectroscopy. Also electrical and mechanical properties of bucky papers prepared from chemically modified tubes were studied and are discussed. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

2. Covalent Functionalization of Arc Discharge, Laser Ablation and HiPCO Single-Walled Carbon Nanotubes.

Author

Abraham, Juergen, Whelan, Paul, Hirsch, Andreas, Hennnch, Frank, Kappes, Manfred, Samaille, Damien, Bernier, Patrick, Vencelová, Andrea, Graupner, Raif, and Ley, Lothar

Subjects
NANOTUBES, CARBON, NITRENES, LASER ablation
Abstract

The work we present here is based on the chemical functionalization of single walled carbon nanotubes (SWCNTs) via the known nitrene reaction. For this work we used single walled carbon nanotubes, produced by the arc discharge, laser ablation and HiPCO technique. The comparison of the maintained functionalized single walled carbon nanotubes with the SWCNT starting material enabled us to draw conclusions on the reactivity of the nanotubes. Our studies revealed a remarkable difference in the behavior of the variety of studied nanotubes, towards chemical functionalization. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

4. Effect of SOCI2 Treatment on Electrical and Mechanical Properties of Single-Wall Carbon Nanotube Networks.

Author

Dettiaff-Weglikowska, Urszula, Skákalová, Viera, Graupner, Raif, Sung Ho Jhang, Byung Hoon Kim, Hyun Jung Lee, Lothar Ley, Yung Woo Park, Berber, Savas, Tománek, David, and Roth, Siegmar

Subjects
*CARBON, *NANOTUBES, *RAMAN spectroscopy, *CHEMICAL bonds, *ELECTRIC conductivity, *CHEMICAL elements
Abstract

Chemical modification by SOCI2 of an entangled network of purified single-wall carbon nanotubes, also known as `bucky paper', is reported to profoundly change the electrical and mechanical properties of this system. Four-probe measurements indicate a conductivity increase by up to a factor of 5 at room temperature and an even more pronounced increase at lower temperatures. This chemical modification also improves the mechanical properties of SWNT networks. Whereas the pristine sample shows an overall semiconducting character, the modified material behaves as a metal. The effect of SOCl2 is studied in terms of chemical doping of the nanotube network. We identified the microscopic origin of these changes using SEM, XPS, NEXAFS, EDX, and Raman spectroscopy measurements and ab initio calculations. We interpret the SOCI2-induced conductivity increase by p-type doping of the pristine material. This conclusion is reached by electronic structure calculations, which indicate a Fermi level shift into the valence band, and is consistent with the temperature dependence of the thermopower. [ABSTRACT FROM AUTHOR]

Published
2005
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results