S. Thomas, T. Swager
Apr 18, 2006
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Influential Citations
106
Citations
Quality indicators
Journal
Advanced Materials
Abstract
Hydrazine, a heavily used industrial chemical, has been implicated as a carcinogen and is readily absorbed through the skin. Its strong reducing power has led to its use as an oxygen scavenger and corrosion inhibitor in various applications involving water-heating systems, as well as a fuel in rocketpropulsion systems. As a result of its toxicity and reactivity, facile detection of hydrazine is also relevant to homeland security. Traditional analytical methods utilized for hydrazine detection include spectrophotometric detection, as well as assorted electrochemical schemes. The expansion of conjugated polymer sensory materials has also led to their application towards the detection of hydrazine. Of primary interest have been the conducting properties of polypyrrole, polythiophene, and polyaniline. To our knowledge, however, amplifying fluorescent polymers (AFPs) have not been explored for hydrazine detection. AFPs show very high sensitivities to quenching analytes such as 2,4,6trinitrotoluene (TNT) via a photoinduced electron-transfer quenching (“turn-off”) mechanism. This sensitivity of fluorescence quenching is due to a combination of interand intrachain exciton transport in thin films. Herein we report a “turn-on” fluorescence detection method for hydrazine vapor with AFPs. We investigated several polymers (P1–P3) for hydrazine detection. These conjugated polymers are structurally related poly(phenylene ethynylene)s (PPEs), varying in their degree of electron density along the polymer chain. The response of P3 to saturated hydrazine vapor (10 s exposure) is given in Figure 1. It is clear from Figure 1 that no new emitting species were generated by exposure to hydrazine since the spectral shape does not change. In addition, the excitation spectrum of the polymer remained the same after the introduction of hydrazine. The other conjugated polymers investigated also showed no change in the shape of their emission spectra upon exposure to hydrazine vapor (see Supporting Information).