關鍵字：silver nanoparticles; star-shaped copolymers; poly(ε-caprolactone); coordination reduction; nanoreactors; catalytic activity.
Silver nanoparticles (Ag NPs) were prepared via
in-situ reduction of silver nitrate (AgNO
3) using polymeric micelles as nanoreactors without any additional reductant. The micelles were constructed from the amphiphilic star-shaped copolymer composed of
poly(ε-caprolactone) (PCL) segment, 2-(Dimethylamino)ethyl methacrylate (DMAEMA or DMA) units and oligo(ethylene glycol)monomethyl ether methacrylate (OEGMA or OEG) units. The Ag NPs stabilized by those star-shaped copolymers were characterized using UV-vis spectrum, DLS, TEM and FT-IR. It confirmed that PDMAEMA exhibited the reducing property unless pH was above 7. The Ag NPs were sphere-like with a diameter of 10-20 nm, which was independent of the architecture of the copolymer and AgNO
3 concentration. Furthermore, the catalytic activity of these Ag NPs was investigated by monitoring the reduction of
p-nitrophenol (4-NP) by NaBH
4. The result showed that the Ag NPs formed by coordination reduction can be effectively applied in catalytic reaction.