Effect of polymers on nitrogen doped multiwalled carbon nanotube for the detection of chemical warfare agent simulant

초록

Chemical Warfare Agents (CWAs) can be recognized as the lethal chemical weapon of mass destruction which is mainly used in chemical warfare or armed conflict between nations. The Organization for the Prohibition of Chemical Weapons (OPCW) has prohibited the use of CWAs, but the threat still remains as it can be misused in terrorism and deliberate conflict. Hence, early detection of the CWAs is crucial to prevent the damage and death of the people. Due to the toxic nature of the CWAs, we use Dimethyl methyl phosphonate (DMMP) as a simulant of nerve agent sarin. Sarin is an organophosphorus nerve agent which disrupts the neuromuscular transmission by inhibiting the enzyme called acetylcholinesterase. In this study, we used the surface acoustic wave (SAW) sensors as a portable detector. We synthesized four sensing materials namely Nitrogen-doped Multiwalled Carbon Nanotube (N-MWCNT), N-MWCNT/Carboxy methyl cellulose (CMC), N-MWCNT/polyaniline (PANI), N-MWCNT/polypyrrole (PPy). Here, we study the effect of polymers such as CMC, PANI, and PPy on the N-MWCNT for the detection of DMMPwith the concentration ranging from 2?10 ppm. These synthesized materials are characterized by using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The synthesized materials were drop coated onto the delay line of the SAW sensor. The results showed that N-MWCNT alone possesses the lowest sensitivity and substantial noise towards the 10 ppm DMMP molecules.When the polymers were added to the N-MWCNT, the results showed enhancement in the sensitivity towards the DMMP molecules and reduction in the signal noise. For the DMMP concentration of 10 ppm, the order of highest sensitivity is N-MWCNT/CMC > N-MWCNT/PANI > N-MWCNT/PPy > N-MWCNT. Hence, synthesized materials have potential to become promising candidates for the detection of CWAs.