Double-channel emission from gold nanoparticles functionalized with a thermo-responsive copolymer ligand: preparation, optical properties and control of catalytic activity

Abstract

Multifunctional fluorescent gold nanoparticles (Au NPs) were obtained in situ with the assistance of a novel thermo-responsive copolymer, p(NIPAM-co-ETMA) (PNE), containing NIPAM units and an episulfide moiety, for the first time. The PNE-decorated Au NPs can emit multiple colors due to the double-channel in their intrinsic luminescence core (460 nm) and electron transfer between the PNE ligand and unreduced Au⁺ on the surface of the Au NPs (530 nm). Moreover, these NPs capped with Au⁺ on the surface were able to efficiently catalyze the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH₄ in an aqueous environment. The catalytic activity can be controlled by thermo-switching due to the sensitive thermally triggered response of PNE.