VOC Sensing Properties of MHDA-Functionalized Multiwall Carbon Nanotubes

The chemical modification of Multi-Walled Carbon Nanotubes (MWCNTs) with a long chain mercapto- acid is reported as a way to improve sensitivity and response time of gas sensors for detecting alcohols, acetone and toxic gases such as DMMP. We have developed sensors employing MWCNTs decorated with gold nanoparticles and modified with a monolayer of 16-mercaptohexadecanoic acid (MHDA). Morphological and compositional analysis by Transmission Electron Microscopy (TEM), Fourier Transform Infra-red Spectroscopy (FTIR) and X-ray photoelectron spectroscopy were performed to characterize the gold nanoparticles and to check the bonding of the thiol monolayer. The detection of aromatic and non-aromatic volatiles vapors by MWCNT/Au and MWCNT/Au/MHDA shows that the presence of the self-assembled layer increases sensitivity, selectivity and ameliorates response dynamics of the sensors.