Polymeric nanowire chemical sensor

We have used a nonlithographic deposition process to form single polymeric nanowire chemical sensors. Oriented polyaniline nanowires, with diameters on the order of 100 nm, were deposited on gold electrodes. The devices showed a rapid and reversible resistance change upon exposure to NH₃ gas at concentrations as low as 0.5 ppm. The well-defined single-wire geometry allows for the characterization of the wire material and the device response. The response times of nanowire sensors with various diameters correspond to radius-dependent differences in the diffusion time of ammonia gas into the wires. The nanowire deposition process, utilizing a scanned microfabricated electrospinning source, presents a general method for interfacing polymeric nanowire devices with microfabricated structures.