Piezoresistive Sensors Based on rGO 3D Microarchitecture: Coupled Properties Tuning in Local/Integral Deformation

An ideal flexible piezoresistive sensor should possess high sensitivity as well as wide sensing range, and provide a stable and excellent response under different deformation, such as local and integral strain. However, these properties are difficult to achieve simultaneously with conventional all-polymer-filled composite, as tuning of one material component always causes the unpredictable change of multiple properties. Here, a strategy is developed to realize a reduced graphene oxide (rGO) based three-dimensional (3D) microarchitecture, where the electrical conductivity and mechanical elasticity of the composite can be tuned simultaneously by only varying the rGO weight fraction. The analysis of coupled properties tuning effect shows that the device applied in local deformation reveals a greater dependence on electrical property, which prefers to low rGO weight fraction and displays a high sensitivity of 0.72 kPa⁻¹ in the 10 kPa linear region. The sensor used for integral deformation is dominated by the mechanical property, which prefers to high rGO weight fraction and shows a gauge factor of 2517 at tensile strain of 100%, far superior to that previously reported. The rationally designed 3D microarchitecture is scalable, low cost, and promising in human–computer interactions, including but not limited to human health monitoring and intelligent wearable keyboards.