Lightweight, Superelastic, and Mechanically Flexible Graphene/Polyimide Nanocomposite Foam for Strain Sensor Application

TLDR

Creating superelastic, flexible 3‑D graphene architectures remains difficult because of structural collapse or plastic deformation. This work presents a simple method to convert fragile reduced graphene oxide aerogels into superflexible 3‑D structures by incorporating water‑soluble polyimide. The rGO/PI composites are fabricated by freeze‑casting followed by thermal annealing. The resulting monoliths are low‑density, highly flexible, superelastic with near‑complete recovery, reversible compressibility, and exhibit strong electrical conductivity, high compression sensitivity, durable stability, and promise for multifunctional strain sensors under compression, bending, stretching, and torsion.

Abstract

The creation of superelastic, flexible three-dimensional (3D) graphene-based architectures is still a great challenge due to structure collapse or significant plastic deformation. Herein, we report a facile approach of transforming the mechanically fragile reduced graphene oxide (rGO) aerogel into superflexible 3D architectures by introducing water-soluble polyimide (PI). The rGO/PI nanocomposites are fabricated using strategies of freeze casting and thermal annealing. The resulting monoliths exhibit low density, excellent flexibility, superelasticity with high recovery rate, and extraordinary reversible compressibility. The synergistic effect between rGO and PI endows the elastomer with desirable electrical conductivity, remarkable compression sensitivity, and excellent durable stability. The rGO/PI nanocomposites show potential applications in multifunctional strain sensors under the deformations of compression, bending, stretching, and torsion.