Detection and classification characteristics of arrays of carbon black/organic polymer composite chemiresistive vapor detectors for the nerve agent simulants dimethylmethylphosphonate and diisopropylmethylphosponate

Alan R. Hopkins, Nathan S Lewis

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Arrays of conducting polymer composite vapor detectors have been evaluated for performance in the presence of the nerve agent simulants dimethylmethylphosphonate (DMMP) and diisopropylmethylphosponate (DIMP). Limits of detection for DMMP on unoptimized carbon black-organic polymer composite vapor detectors in laboratory air were estimated to be 0.047-0.24 mg m-3. These values are lower than the EC50 value (where EC50 is the airborne concentration sufficient to induce severe effects in 50% of those exposed for 30 minutes) for the nerve agents sarin (methylphosphonofluoridic acid, (1-methylethyl) ester) and soman (methylphosphonofluoridic acid, 1,2,2-trimethylpropyl ester), which have been established as ≈0.8 mg m-3. Arrays of these vapor detectors were easily able to resolve signatures due to exposures to DMMP from those due to DIMP or due to a variety of other test analytes (including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar and tetrahydrofuran) in a laboratory air background. In addition, DMMP at 27 mg m-3 could be detected and differentiated from the signatures of the other test analytes in the presence of backgrounds of potential interferents in the background ambient, including water, methanol, benzene, toluene, diesel fuel, lighter fluid, vinegar and tetrahydrofuran, even when these interferents were present in much higher concentrations than that of the DMMP or DIMP being detected. Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with sorption of vapors producing swelling-induced resistance changes of the detector films. To identify and classify vapors, arrays of such vapor sensing elements have been constructed in which each element of the array contains a different polymer as the insulating phase and a common conductor, carbon black, as the conducting phase. The differing gas-solid partition coefficients for the various polymers of the detector array produce a pattern of differential resistance changes that is used to classify vapors and vapor mixtures. The performance of this detector array system towards 2,4-dinitrotoluene, the predominant signature in the vapor phase above land mines, in the presence high concentrations of water or of acetone (as a selected volatile organic carbon vapor), has been evaluated.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsP.J. Gardner
Number of pages12
Publication statusPublished - 2002
EventChemical and Biological Sensing III - Orlando, FL, United States
Duration: Apr 2 2002Apr 2 2002


OtherChemical and Biological Sensing III
CountryUnited States
CityOrlando, FL



  • Chemiresistors
  • Nerve agent simulants
  • Vapor detectors

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

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