A Facile Synthesis of Cu NPs and Ag NPs Coated by PS with Core-Shell Structure by Precipitation Polymerization

Copper nanoparticles (Cu NPs) coated with polystyrene (PS) (Cu NPs@ PS) were prepared by precipitation polymerization. First, Cu NPs were prepared by chemical reduction using cupric acetate as precursor, sodium polyacrylate (PAANa) as stabilizer, and hydrazine hydrate as reducing agent. Then Cu NPs were coated by precipitation polymerization using styrene as monomer, 3-(trimethoxysilyl) propyl acrylate as co-monomer, and 2, 2-azobisisobutyronitrile (AIBN) as initiator. Ultraviolet-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM) results showed that stable composite particles could be synthesized by precipitation polymerization. The amount of PAANa had a significant effect on the size of Cu NPs. The addition of more PAANa resulted in smaller Cu NPs. The spherical Cu NPs became nanowires when increasing the stirring rate from 350 to 700 rpm during precipitation polymerization. Ag NPs@ PS with core-shell structure were also prepared by this method, which appears to be universal.