Wy. Xu et al., OXYGEN SENSORS BASED ON LUMINESCENCE QUENCHING - INTERACTIONS OF METAL-COMPLEXES WITH THE POLYMER SUPPORTS, Analytical chemistry, 66(23), 1994, pp. 4133-4141
Oxygen quenching of [Ru(Ph(2)phen)(3)]Cl-2 (Ph(2)phen = 4,7-diphenyl-1
,10-phenanthroline) has been studied in a diverse series of polymers,
most with a common poly(dimethylsiloxane) (PDMS) component. Systematic
variations in the polymer properties have been made in order to delin
eate the structural features important for satisfactory use of support
s for oxygen sensors. Most measurements were made using homo- or copol
ymers containing a PDMS region, although some measurements were made o
n small ring siloxane polymers. In particular, quenching behavior was
examined as a function of polymer structure as well as the type of and
amount of polar copolymer cross-linkers. Cross-linkers were added to
enhance the solubility of oxygen probes in an otherwise nonpolar polym
er. In addition, hydrophobic silica was added to alter quenching prope
rties. Domain models are used to explain the variations in oxygen quen
ching properties as a function of additives and cross-linkers. These c
onsiderations have led to the most sensitive ruthenium-based sensor re
ported to date. The relative affinity of the different domains for the
complex and the efficacy of the domains for oxygen quenching control
the overall behavior of the sensing response. Guidelines far design of
suitable polymer supports for oxygen sensors are proposed.