Preparation of robust and light-weight anisotropic polyimide/graphene composite aerogels for strain sensors

This study reports the fabrication of a serious of anisotropic composite aerogels comprising polyimide and graphene (PI/G) through a simple and eco-friendly technique. Poly(amic acid) ammonium salt/graphene dispersion, which was produced through the mixture of poly(amic acid), graphene aqueous dispersion, triethylamine, and water, was utilized in the process of creating PI/G composite aerogels employing unidirectional freezing, freeze-drying, and thermal imidization. The PI/G aerogels displayed anisotropic mechanical properties, thermal insulation, and electrical conductivity. The PI/G aerogels with an anisotropic microstructure demonstrated notable rigidity and a high compressive modulus (52.7 MPa) along the axial direction, while displaying favorable flexibility and a low modulus (18.2 MPa) along the radial direction. Furthermore, the PI/G aerogel exhibited anisotropic thermal conductivity (axial: 64 mW m −1 K −1 ; radical: 55 mW m −1 K −1 ). These properties enable the PI/G aerogel to have a wider range of potential applications, especially strain sensors. The research presented herein establishes a simple and eco-friendly strategy for the production of anisotropic PI/G-based composite aerogels.