Preparation of hydrophobic nano-silver colloid and aqueous nano-silver colloid by phase transfer

A novel and facile method to prepare hydrophobic nano-silver colloid and aqueous coordinate was proposed. Chemical reduction of silver nitrate in a tributyl phosphate (TBP) solution containing polyvinylpyrrolidone (PVP) was conducted and stable hydrophobic nano-silver/TBP/PVP colloids were obtained. Adopting a phase transfer process, the as-prepared colloids can be diverted into an aqueous system to obtain hydrophilic nano-silver colloids. The resultant materials were characterized by digital camera, TEM, XRD and UV–vis spectra. The results show that the reaction can be accomplished fast at room temperature and the synthesized colloids can remain stable for a long time, and the mean diameter of silver particles is around 10 nm for both nano-silver colloids. The nano-silver crystalline is face-centered cubic (fcc) structure, and the UV–vis absorbance peaks are at 412 and 420 nm for aqueous nano-silver and nano-silver/TBP/PVP colloids respectively.