Preparation Of Polyimide/Silica/Silver Hybrid Films And Study On The Structure And Properties

In this study, Polyimide/silica/silver hybrid films were prepared via two methods. The first method is the combination of sol-gel method and in situ single-stage self-metallization technique. The second one is preparing SiO₂@Ag nanoparticles, and then blending with polyimide.In the first method, the structure of polyimide films in the thermal curing process and the influence of silica content on the transfer and aggregation of silver particles to the surface of hybrid films were investigated. Films were characterized by transmission electron microscopy, dynamic mechanical thermal analysis, Fourier transform infrared spectroscopy, ultraviolet visible Spectroscopy and mechanical measurement. The results indicated that there was no degradation of polyimide matrix after the formation of silica and silver particles. Silica acted as the nucleus for the silver particles. With the increasing content of silica, more and more silver particles keep in the hybrid films instead of transferring onto the surface of the hybrid films, and the reflections of hybrid films decreased gradually. In the second method, the photochemical reduction was carried out by ultraviolet irradiation in air atmosphere at room temperature. The silica spheres deposited with silver nanoparticles were obtained and characterized by transmission electron microscopy (TEM), field emission scan electron microscopy (FE-SEM), X-ray diffraction patterns (XRD), Ultraviolet visible Spectroscopy (UV) and X-ray photoelectron spectroscopy (XPS). The results showed that the silver nanoparticles deposited on silica spheres are stable metallic crystallinity with a face-centered cubic (fcc) phase after ultraviolet photochemical reduction for 4 hours; Also silver nanoparticles can be designed to different size and content on silica sphere surfaces depending on the irradiation time. With the increase content of SiO₂@Ag nanocomposite particles, the modulus of hybrid films increased gradually, the elongation at break decreased gradually, and the Tg changed slightly.