Abstract
Two different routes turkivish and sol-gel methods are used to synthesize sodium citrate and polyethylene glycol functionalized gold nanostructures. Field emission scanning electronmicroscope (FESEM) analysis confirms spherical-shaped gold nanoparticles (AuNPs) and self-assembled Au nanodendritic (AuNDs) structures. High-resolution transmission electron microscopy (HRTEM) confirmed the spherical and dendritic morphology with particle sizes 9 nm of AuNPs and 3 nm of AuNDs, respectively. An atomic force microscope (AFM) shows average surface roughness (Ra) ∼2.5 nm of AuNPs which is reduced to 1.5 nm in AuNDs. The AuNPs and AuNDs show heterogeneous chemical bonding and thermal stability at high temperatures. Brunauer-Emmett-Teller-based surface area is calculated at around 18 m2/g for AuNPs and 54 m2/g for AuNDs. The creosol red immobilized AuNPs (CR-AuNPs) and AuNDs (CR-AuNDs) sol demonstrate pka around 8.9 and 9.2 at 575 nm, respectively. The CR-AuNDs sol exhibit a time reaction 0.5 s which is relatively high than CR-AuNPs ∼0.6 s. Both Au-structures show non-leachable behavior.
•Turkivish and sol-gel methods are used to synthesize gold nanostructures.•FESEM analysis confirms spherical-shaped gold nanoparticles (AuNPs) and self-assembled Au dendritic (AuNDs) structures.•The AuNPs and AuNDs show thermal stability at high temperatures.•The cresol red immobilized AuNPs and AuNDs sol demonstrates pka around 8.9 and 9.2 at 575 nm, respectively.•The CR-AuNDs sol exhibit a time reaction 0.5r s which is relatively high than CR-AuNPs ∼0.6 s.