ABSTRACT
This chapter describes the quenching by oxygen of the luminescence of dyes contained in a polymer matrix. This matrix is typically a polymer film. In most applications, one imagines that the dyes arc molecularly dispersed (i.e., dissolved) in the film. There arc, howc,·cr, interesting examples where dyes that would normally be insoluble in the matrix arc adsorbed on the surface of silica particles [I], which in turn arc dispersed in the polymer matrix or covalently attached to the surface of controlled porous glass [2). These various dye/polymer systems serve two general applications. The first involves oxygen sensors for monitoring the pressure or concentration of oxygen in a medium in contact with the dyecontaining polymer film. Examples include the determination of oxygen in nuids such as blood [3a.b I in a tumor cell [3c ], or in the gas phase in a variety of environments including one's breath [3d]. The second application involves the usc of polymer lllms containing a luminescent dye to monitor the air-pressure profile across a surface, particularly in moving air. Created as a method for measuring air-pressure profiles for objects such as aviation models in wind tunnels [41, this technique is often refc1Tcd to as "phosphorescence barometry"; and the polymer film applied to the substrate is called "pressure-sensitive paint" (PSP) [5 ]. These techniques arc similar in that both rely on dyes with long excited-stale lifetimes, typically with significant triplet character (phosphorescence).
