Luminescent hybrid coatings prepared by the sol-gel process for textile-based pH sensor

Fluorene and Stilbene based fluorophores were synthesized and characterized by NMR, IR and mass spectroscopy (ESI-MS). These fluorescent dyes were coated onto cotton fabrics by the sol-gel method using Tetraethylorthosilicate (TEOS) and Propyltriethoxysilane (TPES) as silica precursors. Herein, the optical properties of the synthesized compounds and the elaborated fabrics were studied. The luminescent properties of the fluorophores were examined in three forms, as a powder, dissolved in ethanol, and grafted onto the fabric by the sol-gel method. furthermore, the effect of the fluorophore’s concentrations in sol-gel solution on the fluorescence properties of the elaborated hybrid coatings was investigated. The synthesized fluorophores exhibited a good pH sensitivity and a strong wavelength shift in acidic or basic media, ascribed to the protonation-deprotonation of the phenolic groups and pyridine of the fluorophores molecules. Along, we have successfully developed pH-sensitive fluorescent textiles and tested their efficiency in different pH media.