Performance and microstructure characteristics in polyimide/nano-aluminum composites

Polyimide (PI) composites with high dielectric permittivity have received a great deal of attention in the embedded capacitors and energy-storage devices due to its excellent thermal stability and good mechanical properties. In this study, nano-aluminum (Al) particles were introduced into PI to prepare promising PI/nano-Al composite. The results indicated that the dielectric constant of the composite films increased with the increase of nano-Al contents and the highest dielectric constant was 15.7 for a composite film incorporating 15 wt% nano-Al. The microstructures of PI/nano-Al composite have been investigated by scanning electron microscopy (SEM), translation electron microscopy(TEM), synchrotron radiation small angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (XRD). The effects of mixture doping concentration on volume resistivity and loss tangent are analyzed. The correlation effects of the Al nanoparticles on the different factors which influence the dielectric performance in PI matrix such as microstructure, resistivity, and interface of the composites were discussed in detail. This composite film would be possessing potential application in flexible energy-storage devices.