Single-Walled Carbon-Nanotube-Based Chemocapacitive Sensors with Molecular Receptors for Selective Detection of Chemical Warfare Agents

Single-walled carbon nanotubes (SWCNTs) were fabricated using AC dielectrophoresis into chemocapacitive sensors, and molecular receptors were applied for the selective detection of several chemical warfare agents (CWAs). The selective responses toward nerve simulants (G and V), choking and blister agents as well as a pesticide were investigated with specific receptor molecules that were either covalently functionalized or noncovalently coated onto the surfaces of the SWCNTs. The SWCNT-based chemocapacitive sensors showed reproducibility and sensitivity to 200 ppb for several target molecules. The fabricated sensor arrays were assessed for the selective detection of six different CWAs, and the principal component analysis demonstrated their specificity. VX, a real nerve agent, was tested on the fabricated SWCNT-based chemocapacitive sensor coated with a thiourea-functionalized siloxane polymer, and the successful detection of VX at 100 ppb confirmed that our SWCNT-based sensors are suitable for practical applications.