Conjugated polymer sensors: Detection of 2,3-dimethyl-2,3-dinitrobutane


Samuel W. Thomas III, and Timothy M. Swager. Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 18-143, Cambridge, MA 02139
The use of fluorescent conjugated polymer films for the trace detection of highly electron deficient vapors, such as 2,4,6-trinitrotoluene, is well established. Polymers used for this purpose to date, however, are somewhat limited in the scope of analytes to which they respond via fluorescence quenching. This is a result of the photoinduced charge transfer reaction that causes quenching being energetically favorable only for very electron deficient analytes, such as nitroaromatics and quinones. Here we report the preparation of new, low workfunction conjugated polymers aimed at the detection of analytes with less favorable reduction potentials, such as benzophenone and the International Civil Aviation Organization explosive taggant 2,3-dimethyl-2,3-dinitrobutane (DMNB). These polymers, in particular those containing dialkylamino groups, show interesting and relatively unique optical properties. By manipulating both the ground state oxidation potentials as well as the band gaps of conjugated polymers, vapors of these target molecules can be detected.