Interfacial engineering of epoxy/silica nanocomposites by amino-rich polyethyleneimine towards simultaneously enhanced rheological and thermal-mechanical performance for electronic packaging application

As electronic devices move toward miniaturization and high-degree integration, it becomes imperative to use nano-sized silica as a reinforcing filler for epoxy resin in modern electronics packaging industries. However, the use of silica nanoparticles (SNPs) brings about new challenges in filler dispersion and in the balance between the rheology and thermal mechanical performance of epoxy nanocomposites. This study presents a novel strategy aiming to address the above challenges by interface engineering with amino-rich branched polyethyleneimine (PEI) polymer molecules through a facile self-assembly process. This not only enables a considerable decrease (by 79.7%) in viscosity accompanied by a significant improvement in viscosity stability (only 2.7 times increase after 24 h) but also leads to a further CTE reduction of 4.8 ppm/ ° C (equivalent to the effects of around 10 wt% SNPs) relative to the SNPs. This work offers a new direction and efficient approach to develop high-performance epoxy composites for electrical packaging applications as well as provides some fresh insights into the interface-property relationships. Interfacial engineering by surface modification of silica nanoparticles (SNPs) with amino-rich branched polyethyleneimine (PEI) polymer molecules through a facile self-assembly process is developed to simultaneously improve the rheological and thermomechanical properties of SNPs/epoxy nanocomposites for electrical packaging applications.