Synthesis and characterization of hybrid matrix with encapsulated organic sensing dyes for pH sensing application

Films of multi-organic indicators, encapsulated in silica–titania hybrid matrix with CTAB, have been synthesized using sol–gel dip coating method. Two types of stable,dense and uniform matrices were annealed at a 150 ºC within two time intervals 1 h and 2 h by using 0.1 M and 0.5 M indicator concentrations. Nanoparticles are uniformly distributed with size in the range from 15–28 nm. Matrices have high surface area (418.18–441.30 m2/g), which has more capability to sense the broader pH range. Spectroscopic studies showed the establishment of heterogeneous chemical bonding which indicative of stability of matrices with 69% porosity. The response of the sensor is optimum at pH 9.