A highly linear and durable flexible strain sensor based on MoS₂ van der Waals films for soft machines

Flexible strain sensors for soft and deformable mechanical systems are required to deliver high linearity and durability under repeated deformation, which remain challenging for crack-based sensing mechanisms. Here, we report a highly linear and durable flexible strain sensor based on molybdenum disulfide (MoS₂) van der Waals films. MoS₂ nanosheets were prepared via electrochemical intercalation exfoliation and assembled into conductive films dominated by interlayer van der Waals interactions, followed by surface treatment to enable strong bonding with a polydimethylsiloxane (PDMS) substrate. Benefiting from a reversible interlayer sliding dominated sensing mechanism, the sensor exhibits high linearity (R² = 0.999) over a wide strain range, low hysteresis, fast response and recovery behavior, and excellent durability exceeding 40,000 loading–unloading cycles. Furthermore, the sensor shows reliable response under the temperature range from −20 °C to 80 °C, ensuring its applicability across different scenarios. As a representative demonstration, the sensor is integrated onto a flexible gripper to enable deformation monitoring and slip state discrimination. These results highlight the potential of interlayer sliding based strain sensors for advanced soft machine related applications.