Magnetron sputter deposition of silver onto castor oil: The effect of plasma parameters on nanoparticle properties

Magnetron sputter deposition of metals onto low vapor pressure liquids is a clean and straightforward method of nanoparticle (NP) production. Herein, we discuss the production of silver nanoparticles (Ag NPs) via magnetron sputtering of a silver target onto castor oil, a biocompatible and highly available liquid. A state-of-the-Art (bipolar) high-power impulse magnetron sputtering (HiPIMS) was used for the first time for the sputtering onto liquid procedure. The effect of several parameters such as sputter time, applied power, working gas pressure, and type of sputtering plasma (direct current magnetron sputtering (DC-MS) vs. HiPIMS and bipolar HiPIMS) onto NP properties has been studied by UV-vis spectroscopy and transmission electron microscopy (TEM). The scenario of Ag NPs formation is inferred from these analyses, and further supported by mass-spectrometry and quantum-chemistry calculations. Initial Ag NPs formed in castor oil have a diameter ranging from 0.8 nm to 4 nm, its stability is discussed in terms of the plasma-liquid surface interaction and the quantum chemistry data.

Automated summary

Magnetron sputter deposition on low vapor pressure liquids is an effective method for producing metal nanoparticles. In this study, silver nanoparticles were successfully produced by sputtering a silver target onto castor oil using a state-of-the-art HiPIMS technology. The parameters affecting the properties of the nanoparticles were investigated, and the stability of the initial silver nanoparticles formed in castor oil was discussed based on plasma-liquid surface interaction and quantum chemistry data.