Effect of change selectivity for sensing element made of multi-wall carbon nanotube network treated by plasma

Abstract

Multiwall carbon nanotubes (MWCNT) network called "Buckypaper" was made by the vacuum filtration method from MWCNT aqueous suspension. In this way we created multi-wall carbon nanotube (MWCNT) networks featured by randomly entangled pure nanotubes. These networks were applied as gas sensors for organic vapors of ethanol and heptane, polar and nonpolar solvents respectively. The gas response was investigated by electrical resistance measurements. The surface sensitivity and selectivity was then modified by low-temperature reactive surface plasma treatment in different gases. With plasma treatment, we first created the functional groups on the nanotubes surface and latter etch them. These processes changed surface selectivity for detection of organic vapors. The results showed that the MWCNT network electrical resistance increased when exposed to organic solvent vapors. This is reversible process, when removed from the vapors. Therefore, the MWCNT networks show the potential to be used as improved sensing elements for sensitive and selective organic vapor detection in near future.