Enhancing thermal conductance between graphene and epoxy interfaces through non-covalent cation-π interactions

Although graphene has high thermal conductivity, its application in thermal management remains challenging because of the large interfacial thermal resistance between graphene and adjacent materials. This work demonstrates that non-covalent cationic-pi interaction can significantly improve the thermal conductance between graphene and substrate interfaces. Cationic polyacrylamide (CPAM) bridges substrate and graphene with hydrogen bonding and cation-pi interaction, respectively. The cation-pi interaction between graphene and CPAM is confirmed by Raman, UV-Vis and NMR spectroscopy. The results show that CPAM increases the interfacial adhesion of graphene/epoxy from 18.7 +/- 2.2 mN to 37.4 +/- 7.6 mN (100.0 % improvement) and improves the interfacial thermal conductivity (ITC) from 22 +/- 2 MW/m2K to 51 +/- 5 MW/m2K (131.8 % improvement). Enhancing the ITC of graphene/epoxy by introducing CPAM assembled layer has advantages over covalent modifications because it provides a similar level of ITC improvement rate, but has little effect on the intrinsic thermal conductivity of graphene. Finally, it is demonstrated that the sample with graphene/cationic polyelectrolyte/substrate structure exhibits great potential for applications in the area of thermal management and printed circuit boards.