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Effect of Plasma Modification on Dielectric Properties of Polyimide Nanocomposite Films

Al2O3 nanoparticles were treated by plasma and silane coupling agent. Polyimide nano (PI/Al2O3) composite films were prepared by in-situ polymerization. The microstructure of PI/Al2O3 films was observed by scanning electron microscopy and Fourier transform infrared spectroscopy. The structure and functional groups were analyzed, and the broadband dielectric spectrum of the film in the temperature range of -60 to 200 ° C was tested. The results show that after plasma-modified nanoparticles, the nanoparticles are well dispersed in the film and the number of interfaces is increased. There are three relaxation processes α, β, γ in PI/Al2O3 film, which obey the Havriliak-Negami polarization formula. By fitting calculation, the characteristic parameters such as dielectric relaxation time constant and relaxation strength of different relaxation processes at different temperatures are obtained. The relationship between relaxation time and temperature is obeyed by Arrhenius formula, and the activation energy of different relaxation processes is calculated. After plasma modification of nanoparticles, the dielectric loss and activation energy of the film are increased, and the plasma-modified nanoparticles are analyzed. The mechanism of influence of the dielectric properties of the film.