A fast-response pressure sensor based on a dye-adsorbed silica nanoparticle film

An optical oxygen sensor was developed as a pressure-sensitive paint (PSP) to measure time-varying surface pressure in aerodynamic testing. A silica nanoparticle dispersion (slurry) was used as the binder for the sensor, with a pressure-sensitive dye dissolved in the slurry. The dye slurry was deposited onto arbitrary surfaces via spray coating. Thin porous silica films were successfully formed without any organic additives. The pressure and temperature sensitivity of common pressure-sensitive dyes platinum tetra(pentafluorophenyl)porphyrin (PtTFPP)and tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)dichloride ([Ru(dpp)3]Cl2) with a silica/toluene slurry were tested, in addition to the temporal response. The pressure sensitivity was −0.94%/kPa for PtTFPP and −0.64%/kPa for [Ru(dpp)3]2+, which was comparable to the sensitivity of common PSPs. The sensor had good photostability, although it exhibited substantial temperature sensitivity (ca. 1.5%/°C). The response time was less than 0.1 ms for a step rise in pressure obtained using a shock tube.