Flexible, stretchable MXene/polydopamine@Natural rubber-based strain sensor with core-shell structures

In recent years, the demand for flexible strain sensors with high sensitivity and wide detection has increased significantly. Nevertheless, there are few reports on flexible strain sensors that maintain high sensitivity while simultaneously exhibiting an ultra-wide detection range. In this work, a space stacking method is devised to fabricate a Ti3C2Tx (MXene)/polydopamine (PDA)@natural rubber (NR) composite film with a core-shell structure possessing an ultra-wide detection range. With the introduction of PDA into the surface of the NR, PDA has a large number of phenolic hydroxyl groups on the surface. These groups provide abundant active sites for MXene and can form hydrogen bonds with the -F and -O groups on the surface of MXene, thereby strengthening the interfacial interactions. Specifically, the sensing range of the MXene/PDA@NR composite increases by a factor of 1.8 (from 320 % to 896 %) compared to the NR/MXene composite, along with high sensitivity (up to 938.7 for gauge factor (GF)), a short response time (300 ms), and sensing stability (2500 cycles at 50 %). Furthermore, this MXene/PDA@NR strain sensor effectively detects and monitors limb joint movements, and it can even capture subtle changes in the throat during swallowing. Therefore, the MXene/PDA@NR strain sensor holds great promise for integration into flexible wearable electronics.