Stretchable, ultrasensitive strain sensor with high-linearity by constructing crack-based dual conductive network

An increasing attention has been paid to crack-based strain sensors due to their ultrahigh sensitivity. However, two main challenges with such sensors still need to be addressed. Firstly, most crack-based sensors face a trade-off between sensitivity and detection range. Secondly, the problem of low linearity occurs widely among crack-based sensors. This paper presents a simple and efficient method to obtain a multidimensional (1D/2D) crack-based stretchable sensor with dual conductive (electronic/ ionic) network. The process involves creating a hybrid conductive film consisting of Ti3C2Tx MXene nanosheets (MXene) and carbon nanotubes (CNTs) via vacuum-assisted filtration, and developing a flexible substrate with ionic conductivity through convenient UV-initiated curing. The prepared sensor exhibited a broad range of workable strain (0–389 %), high sensitivity (GF = 216.8), rapid response/ recovery (165 ms/ 86 ms) and exceptional durability. Most notably, this strain sensor demonstrates strong linearity (R2 = 0.983) with the synergistic effect of the dual conductive network and cracked hybrid film, an advantage over other crack-based sensors. Therefore, our novel dual-conductive strain sensors, with its superior comprehensive performance, can effectively monitor various large and subtle human movements, including joint bending, pulse, and speech recognition. It is credible that this highly stretchable sensor possesses tremendous potential in human motion monitoring, personal healthcare monitoring, and human–computer interaction.