Polymer-ceramic pressure-sensitive paint with high pressure sensitivity and pressure-sensitivity constancy in low-pressure environments

Abstract

The accurate measurement of tiny pressure variations in low-pressure environments requires pressure-sensitive paint (PSP) with high pressure sensitivity and pressure-sensitivity constancy for aerodynamics testing. In this study, polymer-ceramic pressure-sensitive paints (PC-PSPs) were developed using platinum(II) meso-tetra(pentafluorophenyl) porphyrin (PtTFPP) and palladium(II) meso-tetra(pentafluorophenyl) porphyrin (PdTFPP) as luminophores; titanium dioxide (TiO2) and mesoporous silica (mSiO2) as particles; and poly[1-(trimethylsilyl)-1-propyne] (PTMSP), poly(isobutyl-methacrylate) (PIBM), ethylene-vinyl acetate copolymer (EVA), and polyacrylate (B1000) as polymers. The static characteristics were calibrated and evaluated under low-pressure conditions. The results showed that PC-PSPs using PtTFPP with a short-lifetime and high oxygen-permeable polymer led to high pressure sensitivity. By contrast, if PdTFPP with a long-lifetime was used, the pressure sensitivity was dominated by the luminescence lifetime rather than the oxygen permeability of the polymer. PdTFPP/mSiO2-PTMSP exhibited a remarkable pressure sensitivity of 78.46%/kPa. PC-PSPs employing PIBM, EVA, and B1000, respectively, exhibited excellent pressure sensitivity constancy above 96% after near-vacuum storage for one hour. However, PTMSP-based PC-PSPs exhibited poor pressure-sensitivity constancy owing to the aging of the polymer in vacuum, which can be improved by employing the long-lifetime PdTFPP luminophore and mSiO2 particles. Furthermore, PC-PSPs using mSiO2 particles exhibited lower signal levels, higher pressure sensitivities, lower temperature dependencies and photodegradation than those using TiO2 particles. PdTFPP/mSiO2-PIBM and PdTFPP/mSiO2-B1000 exhibited application potential under low-pressure conditions owing to their favorable static characteristics.