Stable sensors with tunable sensitivities based on class II xerogels.
We report on the analytical figures of merit for O2-responsive sensor arrays and films formed by sequestering tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) within class II organically modified silicates that are composed of tetramethoxysilane or tetraethoxysilane and monoalkylsiloxanes of the form (CnH(2n+1))-Si-(OR)3 (n = 1-12, R = Me or Et). These sensors exhibit a reasonably linear response to gaseous and dissolved O2 (r2 > 0.99), and the sensor responses are stable for over 2 years. Sensor sensitivity can be tuned continuously by adjusting n. For gas-phase O2 detection, changes in the sensor sensitivity depend primarily on the O2 diffusion coefficient within the xerogel phase. The O2 solubility coefficient within the xerogel phase is also a factor but to a lesser degree. For dissolved O2 detection, changes in the sensor sensitivity depend on the O2 diffusion coefficient and the O2 solubility coefficient within the xerogel phase. A linear correlation also exists between the sensor sensitivity and the polarity within these xerogels. Finally, the feature size of pin-printed sensor elements was found to depend linearly on pin velocity. The results of these experiments demonstrate a new strategy for creating xerogel-based sensor arrays consisting of diversified sensor elements for the same target analyte.
Department of Chemistry, Natural Sciences Complex, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, USA.
Zunyu
Z
Tao
Elizabeth C
EC
Tehan
Ying
Y
Tang
Frank V
FV
Bright