An Al@Al2O3@SiO2/polyimide composite with multilayer coating structure fillers based on self-passivated aluminum cores

We demonstrate a capability in combining two kinds of nanosize and microsize particles of core-shell Al@Al2O3@SiO2 with aluminum cores to form multilayer coating structures as fillers in polyimide matrix for electronic applications. The core-shell Al@Al2O3@SiO2 structure can effectively adjust the relative permittivity (about 12 @ 1 MHz) of the composite while keeping lower dielectric loss (0.015 @ 1 MHz) compared to that uncoated aluminum particles. The combination of macro and micro coating can significantly improve the dielectric properties of the composites. This work provides a useful method to modify the fillers for polymer matrix nanocomposite materials. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4798837]