Highly electro-responsive ionic soft actuator based on graphene nanoplatelets-mediated functional carboxylated cellulose nanofibers

Electro-responsive ionic soft actuators have attracted increasing interest owing to the promising applications for soft robots, biomimetic robots, active medical devices, flexible electronics, and wearable devices. However, existing ionic actuators still need a technology breakthrough for larger bending strain, faster response, and excellent actuation durability. Herein, we report a novel highly electro-responsive ionic actuator based on functional carboxylated cellulose nanofibers (CCNF) by doping with ionic liquid (IL) and graphene nanoplatelets (GN). The proposed CCNF-IL-GN actuator demonstrated a large tip displacement of 15.71 mm (peak-to-peak) at 2.0 V with 0.1 Hz, faster rise time (2.9s), broad frequency bandwidth (0.1–3.0 Hz), markedly reduced phase delay, and long actuation durability (98.6% retention for 3 h) without actuation response distortion, all of which were due to the fast-easy ion migration and massive charge transport ability of the designed ionically crosslinked electrolyte membrane, resulting from the strong ionic interactions and crosslinking of CCNF nanofibers with IL and GN. Furthermore, we investigated the actuator's bionic applications such as the bionic flower, bionic finger, and bionic window. These results elucidate the great potential of the designed CCNF-IL-GN actuators for bionic robots, soft robots, wearable electronics, and biomedical active devices.