DEVELOPING MICRO-ELECTRICAL DISCHARGE MACHINING SYSTEM AND APPLICATION IN PREPARING SILVER NANOCOLLOIDS
Abstract - In the present day, silver nanoparticles are often used in biotechnology because of their antibacterial properties. Therefore, how to develop a method to prepare of silver nanoparticle colloids is an important issue in the field of nanotechnology. This study aims to develop a Micro Electrical Discharge Machining (micro-EDM) system with a real-time monitoring and control function to prepare silver nanocolloids.Silver nanocolloids were prepared by a micro-EDM system, including 150 ml deionized water (DW), a silver wire with a diameter of 1mm and a purity of 99%, working procedure parameters, the preparation time was 3.5 minutes, which operates under conditions of room temperature and atmospheric pressure. The analysis of UV-Vis and Zetasizer showed that the prepared silver nanocolloids had the best colloidal properties when working procedure parameter be set, with a wavelength of 392 nm, an absorbance of 0.23, an average particle size of 5.5 nm, and a Zeta potential of -52.4 mV.Transmission electron microscopy can be showed by images, that the shape of the colloidal particles was close to spherical, and the minimum particle size was about 2 nm.The properties of this colloid proved that the electrical spark discharge method could prepare silver nanocolloids with good suspension. When the spark discharge was successful, the interelectrode gap voltage and current were about 100V and 6.4A, as well as duty cycle was 50%, respectively.The principle of method is by converting electrical energy into thermal energy, and no chemical additives are used in the process.The silver nanoparticles have the advantage of toxicity free, which is adapted to use for future applications in human life science and technology.
Keywords - Silver Nanoparticles, Electrical Spark Discharge Method, Dielectric FluidNanocolloids.