Comparative study of the optical behavior of a porphyrin encapsulated in sol-gel silica coatings and in solution as a function of pH

Carmona, Noemi
Villegas, María Ángeles
García, Miguel
Llopis, José
Montero-Zeledón, Ernesto

2016

Carmona, N., Villegas, M., Montero, E., García, M., & Llopis, J. (2016). Comparative study of the optical behavior of a porphyrin encapsulated in sol-gel silica coatings and in solution as a function of pH. Elsevier, 182(1), 315-323.
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Artículo científico

We report a comparative optical spectral study as a function of pH on a porphyrin encapsulated in a solgel matrix and in methanol solution. Its response has been discussed in terms of pH-sensitivity as a function of the coatings thickness. Comparison with the behavior of such porphyrin in methanol solution is also included. Optical properties of the porphyrin doped coatings show a quasi linear behavior throughout the pH range studied. Luminescent emission of doped coatings has its maximum peak at a slightly lower wavelength compared with the response in liquid medium (methanol solution), while in the excitation spectra no clear tendency was observed for different pH. Coatings doped with 1 wt% porphyrin fulfill Lambert-Beer law, although the molar absorptivity of the encapsulated porphyrin in the coatings is slightly lower than in methanol solution.

Research Subject Categories::NATURAL SCIENCES::Chemistry::Physical chemistry::Chemical physics; Ácidez; Sensibilidad; Propiedades ópticas; Revestimientos;