Polydopamine-modified graphene with cellulose nanofibers to act as fillers in epoxy nanocomposites for application in the next generation of green electronic packaging materials

In this work, eco-friendly polydopamine (PDA) modifies graphene (PDA-G) through a π-π stacking interaction. Then, eco-friendly and biodegradable cellulose nanofiber (CNF) polymers are employed to combine with PDA-G to form a 3D thermal transport network. More significantly, their abundant functional groups, including hydroxyl groups and carboxyl groups, form interfacial hydrogen bonding with PDA-G to reduce the thermal interfacial resistance. With fundamental understanding of the interfacial engineering between CNF and PDA-G and with an effort to balance the effects of filler connection and thermal insulation of CNF, the resultant epoxy nanocomposites achieved a high through-plane thermal conductivity of 0.58 W/mK at only 3.05 wt% loading. In addition, the epoxy nanocomposites have a low CTE and high thermal stability. Meanwhile, the potential application of epoxy nanocomposites as thermal interface materials (TIMs) in semiconductor packaging has been demonstrated by both experimentations and simulation. These tests result in new pathways to design and modify fillers to meet the demands of next generation green polymer composites in 2.5D/3D semiconductor packaging.