Application of pressure sensitive luminophores for micro- and nano-systems

Experimental analyses of thermo-fluid phenomena of micro- and nano-flows with high Knudsen number need the measurement techniques based on interaction of atoms or molecules with photons. The pressure sensitive paint (PSP) technique has the capability to be applied to high Knudsen number flows, such as micro-flows and low density gas flows. In this study, to inspect the feasibility of PSP for measurement of pressure on a solid surface in high Knudsen number flows, fundamental properties of PSPs are examined especially in the range of pressure below 1 Torr. As an application of PSP to measurement in high Knudsen number conditions, the pressure distribution on a jet-impinging small solid surface is measured. However, application of the PSP technique to a micro-system is very difficult, because of large thickness of conventional PSPs. Therefore, we have adopted Langmuir-Blodgett (LB) method to fabricate a pressure sensitive molecular film (PSMF) applicable to pressure measurement around micro/nano devices. Finally, the dependence of luminescence intensity of PSP on the molecular number flux onto the solid surface is discussed, because molecular number flux is an important quantity to analyze the interaction between high Knudsen number flows and solid surfaces.