Sensitivity enhanced, highly stretchable, and mechanically robust strain sensors based on reduced graphene oxide-aramid nanofibers hybrid fillers

Recently, high-performance flexible strain sensors with remarkable sensing performance and desired mechanical properties have attracted great attention in the field of wearable electronic devices. However, it is still challenging to realize the tuning of sensitivity and sensing range in graphene-based strain sensors. Herein, a sensitivity enhanced, highly stretchable, and mechanically robust strain sensor is proposed based on reduced graphene oxide (RGO)-aramid nanofibers (ANFs) hybrid fillers and natural rubber (NR) matrix. Due to the strong π-π interactions, the RGO-ANFs hybrid fillers were constructed and orderly assembled around the NR particles, resulting in the formation of a unique interconnected conductive network. The resultant RGO-ANFs/NR strain sensors exhibited significantly improved sensitivity (gauge factor up to 870), wide detection range (0 ∼ 226%), expected mechanical properties (tensile strength >6 MPa), excellent stability, repeatability, and durability (1000 cycles), as well as fast feedback (response time of 195 ms). The strain sensor could monitor joint movements and physiological activities in real time at a wide temperature range (-20 ℃ ∼ 60 ℃), demonstrating the prospect as a flexible wearable device that could be applied under various temperature conditions.