Flexible carbon nanotube vapor sensors

Single walled carbon nanotubes (SWNTs) on a flexible poly(ethyleneterephthalate) (PET) substrate were evaluated for their use as vapor sensors. These easy to construct sensors were fabricated using the Line-Patterning method. A '4-probe' sensor pattern was drawn onto PET using a PC. The PET was then dip-coated in an aqueous surfactant-supported dispersion of SWNTs. Change in resistance values (%DeltaR/R) were obtained for a variety of solvent vapors. Experiments conducted at 10,000 ppm showed good solvent correlation with the solvent polarity scale [ET(30)]. These sensors have been shown to be effective even while being bent.; Building upon findings that the SWNT/PET sensors are effective at vapor detection, the sensors were evaluated for their ability to detect the nerve agent simulants diisopropylmethylphosphonate (DIMP) and dimethylmethylphosphonate (DMMP). It was found that the SWNT/PET sensors had a much larger response to DIMP, and DMMP than to other organic molecules. This large response is believed to be due in large part to the simulants strong electron donating character.; In order to enhance the vapor detection properties of the SWNT/PET vapor sensors, chemoselective polymers were evaluated. The polymers polyethyleneimine (PEI), polyisobutylene (PIB), and Bis-phenol-3 (BSP3) were studied. PEI is a basic polymer designed to adsorb acidic solute vapors. PIB is a non-polar polymer used to adsorb non-polar vapors, and BSP3 is an acidic polymer, designed to adsorb basic solute vapors.