Flexible hdC-G reinforced polyimide composites with high dielectric permittivity

Carbon nanotubes (CNTs) reinforced composites with high dielectric permittivity empower miscellaneous applications in flexible electronics but are hindered by the large addition and agglomeration of fillers and weak mechanical performance. Here, we prepare homogeneous dispersion of CNTs and graphene oxide (hdC-G) via solvent-exchange, and fabricate hdC-G/polyimide (PI) composite films by in situ polymerization and thermal imidization. The achieved hdC-G can construct a 3D network and keep a long term stability. The hdC-G/PI composites show high dielectric permittivity of 124.9 at 100 Hz, 4000% higher than that of pure PI. The hdC-G/PI composites also exhibit enhanced thermal stability and improved tensile strength without sacrificing the flexibility. This solvent-exchange approach can greatly enrich the applications of synergistic uses of CNTs and GO in composites and the hdC-G/PI composites with simultaneously high dielectric permittivity, low content of fillers, good mechanical and thermal performances can be good candidates for flexible electronics.