Universiti Teknologi Malaysia Institutional Repository

Optically active phenolphthalein encapsulated gold nanodendrites for fiber optic pH sensing

Islam, Shumaila and Bakhtiar, Hazri and Aziz, Madzlan and Riaz, Saira and Abd. Aziz, Muhammad Safwan and Naseem, Shahzad and Elshikeri, Nada (2019) Optically active phenolphthalein encapsulated gold nanodendrites for fiber optic pH sensing. Applied Surface Science, 485 . pp. 323-331. ISSN 0169-4332

Full text not available from this repository.

Official URL: http://dx.doi.org/10.1016/j.apsusc.2019.04.210


Herein, sol-gel based synthesis of poly ethanol glycol assisted gold nanodendrites (AuNDs) is reported at low-temperature. Taking advantage of its facile synthesis, phenolphthalein (phph) is encapsulated/immobilized in AuNDs for the assay of fiber optic pH sensing. Hierarchical structure is observed by FE-SEM analysis before and after phph encapsulation. EDX analysis confirms the uniform distribution of elements with smooth morphology. AFM analysis shows that phph encapsulated AuNDs have low average roughness (2 nm) and less thickness ~20 nm. The chemical bonding between phph species and Au molecules are explored by FTIR analysis. The polycrystalline nature of AuNDs matrix before and after encapsulation is confirmed by XRD. HR-TEM analysis exhibited preferential growth of dendrites structure before and after encapsulation along (111) direction. UV–Vis analysis shows that AuNDs has refractive index 1.24 at 550 nm, which reduces down to 1.18 at 550 nm after phph encapsulation. 30 cm coated middle segment of plastic clad silica fiber (PCS) is used as sensor. Variations in output intensities in terms of transmission are used to characterize the sensor response. A fast response ~0.87 s, repeatability/reproducibility and linear response (R2 = 0.8912) is obtained at 440 nm. Acidity of rainwater (pH 6) is determined by prepared sensor for validity purpose and practical applications.

Item Type:Article
Uncontrolled Keywords:Gold nanodendrites, Phenolphthalein
Subjects:Q Science > QC Physics
ID Code:87442
Deposited By: Widya Wahid
Deposited On:08 Nov 2020 11:59
Last Modified:08 Nov 2020 11:59

Repository Staff Only: item control page