| AVS 57th International Symposium & Exhibition | |
| Plasma Science and Technology | Friday Sessions |
| Session PS-FrM |
| Session: | Liquids and Multiphase Discharges |
| Presenter: | N. Saito, Nagoya University, Japan |
| Authors: | N. Saito, Nagoya University, Japan Y. Aoki, Nagoya University, Japan J. Hieda, Nagoya University, Japan O. Takai, Nagoya University, Japan |
| Correspondent: | Click to Email |
Plasma in gas phase is widely used in many industrial fields such as electronic device manufacturing processes (plasma etching, sputtering, plasma-enhanced CVD, etc.), hard coating processes (ion plating, sputtering, etc.), surface treatment processes (low or atmospheric pressure plasma treatments, sputtering, plasma etching, etc.) and so on. Plasma in solid phase has been utilized finally for surface plasmon resonance (SPR) spectroscopy, nanoparticles, etc., and plasmonics is developing as a new research field. On the other hand, plasma in liquid phase is not generally well-known, although it has been partially utilized in water treatments and electrical discharge machining. The fundamentals of plasma in liquid phase have not been established, including its generation techniques, its state, and activated chemical species. However, it would be reasonable to expect a higher reaction rate under lower-temperature conditions, and the greater chemical reaction variability since the molecular density of liquid is much higher than that of gas phase. So we have named the plasma in liquid phase “solution plasma” because we make variety of plasma by choosing the combinations of solvents and solutes in solutions, and are developing solution plasma processing (SPP). In SPP, aqueous solutions, nonaqueous ones, liquid nitrogen, supercritical fluids, etc. can be utilized as solutions. Recently, we have investigated the features of SPP and the applications such as syntheses of nanoparticles and mesoporous silica, and surface modification of particles.
In this research, copper nanoparticles were synthesized by a glow discharge in solution. A pulsed power supply was used to generate discharges. The pulsed width was 2 micro seconds, the repetition frequencies were 10 – 15 kHz. The electrode was tungsten wire in the diameter of 1 mm with electrode gap of 0.3 mm. Ethanol was used as a solution. Monohydroxy copper acetate (II) was utilized as a raw material of copper. The molar concentration of raw material was adjusted to 5mM. Moreover sodium iodide was added to the solution up to 5 mM. The solution and the productants after the discharge were analyzed by 1H NMR, Uv-Vis spectroscopy, XRD, TEM. Finally, TEM showed the synthesis of copper nanoparticles. Moreover 1H NMR show the presence of acetaldehyde in the solution after discharge, which might work as a reducing agent.