Optimal design and fabrication of stable ordered porous conductive structure for flexible strain sensors with high sensitivity and linearity

The increasing utilization of wearable electronics in human-computer interaction and medical health urges the rapid development of flexible strain sensors. However, it is still a challenge to fabricate flexible strain sensors with high sensitivity, linearity, and stability. Herein, we presented a freezing/magnetic orientation approach to construct dual-ordered porous conductive networks based on the reduced graphene oxide (rGO)/Fe nanowire (NW)/carboxymethyl cellulose (CMC) to optimize the sensing performance of the flexible strain sensors. Owing to the stable and ordered porous conductive network constructed by ice template-assisted rGO and magnetic field-induced Fe NW, the sensing performances of rGO/Fe NW/CMC ordered network composite were significantly improved. The prepared rGO/Fe NW/CMC strain sensor demonstrated a high gauge factor of 112.44, which was 426.90 % and 108.06 % higher than the samples with only ordered Fe NW network and only ordered rGO network, respectively. Meanwhile, the rGO/Fe NW/CMC strain sensor presented a linearity of 0.99 and a stability over 3000 dynamic stretching cycles, which was better than the sample without Fe NW and ordered rGO network. Owing to the excellent sensing performance, the rGO/Fe NW/CMC strain sensors were successfully used to monitor the human gestures, indicating the potential as practical wearable devices for real-time motion detection in human-computer interaction and medical health.