Flexible, conductive, and highly pressure-sensitive graphene-polyimide foam for pressure sensor application

Three-dimensional porous graphene foams have received increasing attention in the fields of sensors, flexible conductors, and energy storage. Mechanical stability, flexibility, and electrical conductivity are prerequisites for materials used in these fields. In this paper, novel polyimide-based graphene foam was prepared by dip-coating a polyimide foam template followed by chemical reduction and thermal reduction. The prepared foam displayed excellent mechanical stability and flexibility (elastic modulus: similar to 5 kPa). The synergistic effects of chemical and thermal reduction led to a foam with high electrical conductivity of similar to 0.4 S m(-1). By controlling the dip-coating times, the foam achieved a high pressure sensitivity of 0.36 kPa(-1). Experiments show that the prepared foam can be used as effective pressure sensor to measure heartbeat, joint activity, and airflow.