Studies on the fabrication and characterization of optical sensor coatings for aerodynamic applications

Abstract

Optical sensor coatings for measurement of surface pressure on aircraft models are based on the principle of oxygen quenching of luminescence. Such luminescent sensor coatings were fabricated by immobilizing luminescent dyes in a suitable polymer matrix. The pressure sensitivity of the sensor coatings depends on the parameters associated with the Stern-Volmer constant, K SV. These factors include the luminescence lifetime, τ o of the luminophore and the oxygen quenching rate constant, k Q of the luminophore in the polymer matrix. In the present study, two platinum porphyrin complexes, namely, platinum octaethylporphyrin (PtOEP) and platinum tetrakis (pentafluorophenyl) porphyrin (PtTFPP) were used as the luminescent dyes for the pressure sensor coatings owing to their strong luminescence, long excited state lifetimes, visible light absorption and large Stokes' shifts. The sensor coatings were prepared by doping PtOEP and PtTFPP in polystyrene (PS). The effect of luminophore concentration on photophysical characteristics and oxygen sensitivity was studied. The oxygen sensitivity of PtOEP/PS and PtTFPP/PS coatings were found to be 84 and 71%, respectively. The stability of the coatings was assessed by normal aging and thermal aging tests. The oxygen sensing of the coatings were also studied using lifetime measurements and discussed. The results suggest that these coatings were found to have good potential for the measurement of surface pressure distribution on aircraft models in wind tunnel studies. © 2012 Asian Network for Scientific Information.