Fluorescence Quenching Kinetics of Py Excimer in PS Films

Abstract

ABSTRACTExcimer fluorescence of two-component thin films made of pyrene (Py) and polystyrene (PS) can be quenched by the vapor of nitro-aromatic and nitro-ester explosives with a high selectivity and sensitivity. Normally, an electrospun film can be quenched in minutes by the vapor of the explosives. In order to understand the origin of the mechanism, we have investigated the fluorescence quenching rate of the binary thin films as functions of the molecular weights (MW) of the polystyrene (from 2,500 to 900,000 g/mol) and film thicknesses (110nm and 610 nm) in presence of the vapor of 2,4-dinitrotoluene (2,4-DNT, a type of nitro-explosives). The diffusion coefficients of 2, 4-DNT in the solid films are found nearly independent of MW but have strong dependence on the film thicknesses.