Self-assembled microstructures with localized graphene domains in an epoxy blend and their related properties

Abstract

Locating nanoparticles in selected areas via the mixing of two immiscible polymers is widely studied for achieving nanocomposites with next-level performance, however, the formation of a phase-separated domain constructed with nanofillers from entirely miscible molecules is rarely achieved in the literature. Here we demonstrate a method to fabricate a self-constructed bi-continuous phase structure with localized amine-functionalized graphene nanoplatelets (A-GNPs) in a liquid processable multi-component epoxy blend. Atomic force microscopy infrared spectroscopy (AFM-IR) was employed to identify the compositions of the phase-separated microdomains formed during self-assembly by A-GNP in the multi-component epoxy blend, with incorporating 1-(2-aminoethyl) piperazine (AEPIP) found to be the driving force for the formation of the graphene microdomains. Nanoindentation measurements show that a Young’s modulus of 6.3 GPa for the graphene domain was achieved, which is nearly twice that of the epoxy resin (3.2 GPa). Transient thermoreflectance results indicate that the thermal conductivity of nanocomposite with phase-separated graphene domain reached 0.48 W/mK, exhibiting a significant enhancement (70%) when compared to epoxy resin, while maintaining excellent dielectric properties. Overall, this study provides a simple and effective route to fabricate phase-separated microstructure with nanoparticles from a liquid processable nanocomposite blend, which shows the great potential of this promising new approach to fabricate nanocomposite films with excellent performance for microelectronics applications.