Formation of Carbon Nanotube Bucky Paper and Feasibility Study for Filtration at the Nano and Molecular Scale

Abstract

Presence of abundant pores and highly entangled nanotubes make bucky paper (BP) a natural candidate for filtration related applications. Both single- and multiwall carbon nanotube (SWNT and MWNT) BPs were fabricated via self-assembly. Average diameter of the pores on the surface of MWNT BP appeared to be 33 ± 15 nm. However, due to the high tortuousity of BP, the cutoff size, estimated by filtration of colloidal dispersions of Au and CdS nanoparticles of different diameters, turned out to be 4–5 nm. The particle sizes were verified using microscopic and spectroscopic methods. The flux of Au nanoparticle solutions through BP was about 1000 L h–1 m–2 bar–1. Highly flexible and robust SWNT BPs were prepared very easily, even without proper dispersion. It was found that the crystallinity and purity of the SWNTs had a bigger role than the quality of dispersion in determining the final mechanical strength of BP. The density of SWNT BP was estimated to be 1.3 ± 0.3 g/cm3 after correcting for the weights of the i...