Fabrication of a Microscale Device for Detection of Nitroaromatic Compounds

Polymer layers displaying a specific swelling response in the presence of nitroaromatic compounds are integrated into microscale sensors. Blanket layers of the polymer are grown using initiated chemical vapor deposition, and lithographic techniques are used to define microscale polymer lines. A nanoscale metal line is perpendicularly overlaid across each polymer line. Exposure to nitroaromatic analytes causes the polymeric device component to expand, resulting in plastic deformation of the metal and a permanent change in the resistance measured across the device. The response is rapid and selective for nitroaromatic compounds; additionally, the small area, simplicity, and interchangeability of the device design facilitate the fabrication of sensors selective for other analytes and device arrays. Calculated limits of detection for 2,4,6-trinitrotoluene are 3.7 ppb at 20^°C or 0.8 pg in a proof-of-concept device; methods for optimization are explored.