Sol-gel based phenolphthalein encapsulated heterogeneous silica-titania optochemical pH nanosensor

Thermally stable phenolphthalein encapsulated silica-titania nanomatrix is fabricated by sol-gel method for optochemical pH sensing. The particle size similar to 56-121 nm is obtained with average surface roughness of 3.95 nm after the encapsulation of dye which is highly appropriate for optical and sensing applications. High surface area value similar to 218 m(2)/g, pore volume of 0.16 cm(3)/g and pore diameter of 31.49 angstrom is obtained after encapsulation. Furthermore, the sensor response is optimized at pH 10. Fast response time 1-2 s, sensitivity with good reproducibility identify that the fabricated optochemical nanosensor is challenging for the detection of pH at room temperature. (C) 2015 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.