Flexible and shape-configurable PI composite aerogel films with tunable dielectric properties

Abstract

In the past decade, the development of polyimide (PI) aerogel films has drawn a great attention due to their enhanced physical and mechanical performance compared to conventional bulk monolithic aerogels. However, their ultralow dielectric constant has limited their application in energy-related fields mainly energy storage and energy harvesting. Therefore, it is of great interest to improve and tailor the dielectric properties of PI aerogel films. This work presents the fabrication of novel PI composite aerogel films with tunable dielectric properties based on sol-gel approach combined with graphene nanoplatelet fillers. The structural analysis of aerogels indicated the addition of graphene resulted in altering the aerogel nanostructure by improving the homogeneity and uniformity of composite gel films. When the mechanical properties were evaluated, aerogels displayed excellent flexibility, improved mechanical properties, and outstanding machinability. This was accompanied by significant improvement in thermal stability of aerogels. Eventually, inclusion of graphene nanoplatelet was identified as an effective strategy for tailoring dielectric properties of aerogels and this was attributed to enhancement of interfacial polarization's density.