Super-elastic graphene/carbon nanotube aerogels and their application as a strain-gauge sensor

Abstract

A synergistic assembly strategy was developed to fabricate super-elastic all-carbon aerogels by integrating carbon nanotubes (CNTs) into three-dimensional graphene. The CNTs in the aerogels prevented the sliding between the graphene sheets and enhanced the stiffness of cell walls, which provided the aerogels with super-elasticity. Mechanical tests showed that the graphene/CNT aerogels could fully recover without fracture even after 90% compression. The potential application of the sensing compressive strain for the aerogels was also demonstrated. The electrical resistance response of the aerogels was highly constant to the multiple cycles of compression. The strain-gauge sensitivity of graphene/CNT aerogels could be tuned to considerably different values by controlling the aerogel density. Upon applying a strain of 30% and 60% to the graphene/CNT aerogel with a density of 37.8 mg cm⁻³, its strain-gauge sensitivities (gauge factor) reached 230% and 125%, respectively, which were superior to most of carbon-based compressible conductors.