Robust Fluorescent Detection of Iodine Vapor by a Film Sensor Based on a Polymer of Intrinsic Microporosity

Rapid and high-fidelity detection of radiological iodine species are of extreme importance for the safety of the population and the environment in nuclear fuel reprocessing or in case of nuclear accidents. A simple and universal method to fabricate the sensor to user-friendly devices toward a desired analytical environment would further benefit its applications. Herein, we describe the success of using luminescent spectroscopy for off- and on-line detection of gaseous iodine by a fluorescent film sensor based on a polymer of intrinsic microporosity (PIM-1), a material that possesses intrinsic signal amplification capability and good solubility for processing into desired morphologies. Due to the photoinduced electron transfer (PET) effect, the fluorescence of PIM-1 is quenched drastically upon I2 exposure, but not much altered by H2O, CO2, or H2S. An off-line I2 sensor of free-standing PIM-1 membrane and a real-time flue I2 detector by coating PIM-1 film inside a capillary tube were fabricated and applied. Quick response (few seconds), high signal–noise ratio (five orders of magnitude), low detection limit (few ppb), steam tolerability, as well high reversibility and reusability were achieved, making the material a practically convenient and efficient I2 sensor.