Noncovalent engineering of carbon nanotube surface by imidazolium ionic liquids: A promising strategy for enhancing thermal conductivity of epoxy composites

Abstract

Carbon nanotubes reinforced polymer composites with high thermal conductivity show attractive prospects as multifunctional thermal management materials for high-power electronics applications. The contradictory relationship between homogenous filler dispersion with enhanced interfacial interaction and the intrinsic properties of embedded filler, usually leads to the uncertainty and low thermal conductivity improvement efficiency of resulting polymer composites. Herein, noncovalently functionalized multi-walled carbon nanotubes with imidazolium amine-terminated ionic liquids (AIL-MWCNTs) were facilely prepared through cation-π stacking interactions and acted as low-defect fillers for improving the thermal conductivity of epoxy. The mild chemical modification process has considerable advantages for reserving the inherent intact structures of MWCNTs. Hence, the thermal conductivity enhancement of EP/AIL-MWCNTs composite (∼211%) is much higher than that of epoxy composite filled with acidified MWCNTs (∼102%) at 8 wt% loading. The noncovalent functionalization approach is a promising strategy for scalable fabrication of MWCNTs-based polymer composite with simultaneously enhanced thermal conductivity and mechanical properties.