Effects of a Gaseous Atmosphere on the Pressure Sensitivity and Constancy of Pressure-Sensitive Paints

Pressure-sensitive paint (PSP) technology is an innovative optical measurement method that has been applied towards studying the aerodynamic characteristics of Martian spacecraft under low-pressure conditions. In this study, the static characteristics and constancy of the oxygen pressure sensitivity of PSPs fabricated using either poly[1-(trimethylsilyl)-1-propyne], particle-ceramic, or mesoporous silica particles as binders were studied under low oxygen pressure conditions using various gas mixtures with oxygen pressure ratios ranging from 1% to 20.9%. The results showed that the oxygen pressure ratio did not affect the oxygen sensing property and temperature dependency. PTMSP-PSP exhibited the highest oxygen pressure sensitivity of 26.78%/hPa and the lowest temperature dependency of -0.22%/K among the three PSPs under low oxygen pressure conditions. By comparing the oxygen pressure sensitivities before and after stored in different gaseous atmospheres, the degradation of PTMSP-PSP was verified to be related to the total pressure and unrelated to oxidation, and the degradation declined as the total pressure was increased. The static calibrations conducted in gaseous atmospheres with high total pressure and low oxygen pressure ratio not only improve the constancy of PTMSP-PSP and avoid the calibration error under low pressure conditions, but also alleviate the stringent sealing requirements of the test system.