Thermally stable and fast responsive mesoporous cresol red functionalized silica and titania nanomatrices: Fiber optic pH sensors

• Main Authors: Islam, Shumaila, Aziz, Muhammad Safwan, Bakhtiar, Hazri, Harun, Sulaiman Wadi, Riaz, Saira, Naseem, Shahzad
• Format: Article
• Published: Springer Verlag 2021
• Subjects: Q Science (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.um.edu.my/28485/
• Institution: Universiti Malaya

Owing to the fast responsive fiber optic pH sensing, silica nanomatrix (SNM) and titania nanomatrix (TNM) are synthesized by the sol-gel method at low temperatures. Cresol red (CR) is immobilized within SNM and TNM for sensing evaluation. Crack-free, crystallinity and porous surfaces with an average particle size of CR-SNM similar to 45 +/- 0.4 nm and CR-TNM similar to 24 +/- 0.4 nm are observed through microscopic analysis. The is observed in CR immobilized matrices. The CR-SNM shows lower roughness similar to 7 nm, a large surface area similar to 380 m(2)/g, thermal stability at <= 400 degrees C, and a refractive index 1.47. Whereas, CR-TNM revealed high roughness 48 nm, surface area 211 m(2)/g, and refractive index 1.76. The sensitivity of the CR-SNM coated fiber is estimated at around 52.8 counts/pH which is greater than CR-TNM coated fiber sensitivity 14.53 counts/pH. Moreover, CR-SNM shows response time 0.17 s at pH 12 which is faster than CR-TNM time response 0.48 s. GRAPHICS] .