Within the DESYGN-IT research project, funded by the European Commission, carbon nanotubes (CNT) were investigated in the form of powder, vertically grown on a Si substrate and as CNT sheets or mats, mostly referred as to "bucky paper". Due to their hydrophobic and inert nature, functionalization or alteration of nanotubes can be necessary to optimize them for desired applications. The low pressure glow discharge treatment was investigated in terms of their ability to increase the wettability of bucky papers produced from multi walled carbon nanotubes (MWNT) powders. Hydrophilized bucky papers are required for their use as actuators in an electrolyte solution or a substrate for cell cultures. The opening of end caps of aligned grown CNTs based on plasma treatment was a second aim. The as-produced carbon nanotube materials (powder, bucky paper, aligned structures) as well as the plasma treated samples were characterized by surface analytical techniques like SEM, ESCA, TGA, BET to find optimized parameter sets. By using oxygen containing plasmas, the increase in wettability of CNT mats could be successfully shown. Plasma polymerisation of a carbofluorine monomer onto a bucky paper leads to superhydrophobic surfaces. We found that under gentle oxidation parameters the vertical alignment of MWNTs remains unchanged whereas more harsh conditions destroy the CNT shape without opening the end caps.
Vohrer, U., Holmes, J., Li, Z., Teh, A., Papakonstantinou, P., Ruether, M., & Blau, W. (2007). Tailoring the Wettability of Carbon Nanotube Powders, Bucky Papers and Vertically Aligned Nanofibers by Plasma Assisted Functionalization. Journal of Nanotechnology, 3, 1-12. https://doi.org/10.2240/azojono0126