Nanophase separated amphiphilic polymer co-networks as efficient matrices for optical sensors: Rapid and sensitive detection of NO2

A disposable and irreversible sensor for nitrogen dioxide detection, based on the reaction of NO2 with N,N′-diphenyl-1,4-phenylenediamine (DPPD) is described. This work focuses on the application of silicone-containing amphiphilic co-networks (APCNs) as immobilisation matrices for UV/VIS transmission spectroscopy for gas sensors. The developed flow-through gas sensor is based on a DPPD doped APCN, for real-time spectrophotometric detection of the oxidation product, and is formed in a 34 μm thin film. The measurement principle presented here describes the NO2 concentration as a function of the temporal development of absorption at 450 nm. A linear relationship between the change of absorption and the concentration of NO2 at different humidity is obtained in the range from 0.1 to 5.0 ppm at ambient temperatures. As a consequence, the sensor response is reproducible with a very low detection threshold (20 ppb) and detection times within seconds.