Research On Synthesis And Properties Of Silver Nanoparticles And Its Nano-composite Particles By Laser

Ag nanoparticles have stable physical and chemical properties, with a superior performance in antibacterial, electricity, optics and catalytic. They can be widely applied in antimicrobial materials, catalyst materials, conductive slurry and electronic components encapsulation field, which have wide application prospects. However, Ag nanoparticles are easy to reunite with high surface energy, enabling nano effects weaken. The Ag and SiO2 composite can improve the silver particle dispersion, reduce cost and obtain unique properties, such as optical adjustability and optical nonlinear enhancement effect. Ni is an important kind of ferromagnetic material. We compound it with composite target material of Ag and SiO2, making nano particles magnetic. It is of great benefit for the separation and recycling of nano particles. It has important scientific significance and a wide range of applications to carried out with a new synthesis technology of Ag nano-composite particles.In this thesis, a new method named pulse laser vapor evaporation-liquid collection was used to prepare Ag and its nano-composite particles. The morphology, organization structure, optical properties, magnetism and antibacterial property of nanoparticles are studied by using special instruments, such as TEM, XRD, FT-IR, UV-Vis, VSM. It indicated that the Ag and its nano-composite particles prepared by the method were 10-40nm in size. The nanoparticles were spherical and ellipsoidal. Partial particles appeared layer structure. Analysis of EDS indicated that SiO2 and Ni were found in the surface layer of particles. The UV-Vis absorption peak of Ag nanoparticles was 420nm. However, their compound particles had happened to the different degrees of blue shift, which made it obtained tunable optical. XRD and FT-IR indicated that nano-composite particles had Ag, SiO2 and Ni. The saturation magnetization strength of nano-composite particles had certain enhancement by adding Ni to Ag/SiO2 composite target. MIC and MBC of Ag/Ni/SiO2 nano-composite particles were 0.15625 mg/mL and 0.3125 mg/mL by two times dilution method and bacteriostatic circle method. It indicated that nano-composite particles had a good antibacterial effect.