Synthesis and anisotropic self-assembly of Ag nanoparticles immobilized by the Pluronic F127 triblock copolymer for colorimetric detection of H2O2

Abstract

With dopamine as a reducing and sticking agent, triblock copolymer poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO), Pluronic F127, was employed to immobilize and stabilize silver nanoparticles (Ag NPs) by the chemical reduction of silver nitrate, AgNO₃. Thus, a ternary system comprising Ag NPs, dopamine and F127, i.e. a Ag@DA@F127 system was constructed. In this ternary system, Ag NPs were anisotropically self-assembled and uniformly dispersed in network-like F127 micelles. As evidenced the dispersion stability of Ag NPs in this system was significantly enhanced compared to the Ag@DA and Ag@NaBH₄@F127 system, which in turn resulted in a more sensitive and quantitative detection of H₂O₂. Further investigation demonstrated that the Ag@DA@F127 system exhibited a UV-vis absorption band at ∼405 nm and the intensity of this absorption band dramatically decreased linearly over the concentration range of 0.1–100 μM H₂O₂ (r² = 0.99056), deriving a detection limit of 33 nM, which was superior to recent reports. Apart from its excellent performance in H₂O₂ detection, this Ag@DA@F127 system has other benefits including facile and simple, being environmentally friendly, and especially the formation of a specific network-like structure to fully disperse Ag NPs, which makes it practical in H₂O₂ detection.