Reliable, doped hybrid xerogel-based optical fibre sensor for pH monitoring for industry

A new optical fibre pH sensor has been developed based on incorporating the pH indicator in a hybrid siliceous xerogel. Here the hydrophobic siliceous materials were fabricated using the sol-gel method, employing an optimal percentage of organic precursor moieties, propyltriethoxysilane:tetraetoxysilane, then doping it with three different pH indicators (phenolphthalein, bromophenol blue and cyanidin blue), to create three different optical fibre sensor systems (5pTEOSPH, 5pTEOSBF and 5pTEOSCB). These pH sensors exhibit important features needed by industry: fast response times, minimal dye leaching, good stability, a high level of reproducibility, and reversibility in response. Sensors of this type have a number of important potential uses in different applications in industry today.