Dual sensing of pO(2) and temperature using a water-based and sprayable fluorescent paint

Core-shell particles (CSPs) composed of a polystyrene core and a poly(vinyl pyrrolidone) shell were dyed with a luminescent platinum(ii) porphyrin probe for oxygen. In parallel, microparticles were dyed with a luminescent iridium(ii) complex acting as a probe for temperature. The particles were deposited (by spraying) on a surface to enable continuous imaging of the distribution of oxygen (and thus of barometric pressure) and temperature. Unlike most previous paints of this kind, a binder polymer is not needed and water can be used as a dispersant. This makes the paint environmentally friendly and reduces costs in terms of occupational health, clean-up, and disposal. Both indicator probes in the sensor paint can be excited at 405 nm using LEDs or diode lasers, whilst their emission maxima are spectrally separated by about 130 nm. Thus, two independent optical signals are obtained that allow for fluorescent imaging of barometric pressure (in fact oxygen partial pressure) and of temperature, and also to correct the oxygen signal for effects of temperature. The paint was calibrated at air pressures ranging from 50 mbar to 2000 mbar and at temperatures between 1 degrees C and 50 degrees C.