Building a multi-performance wearable rubber-based strain sensor: for human motion capture, optical heating and underwater sensing

Flexible and stretchable strain sensors have become the main candidates for wearable human devices in recent years. However, existing strain sensors often neglect the multi-performance development and the challenges in practical applications. In this study, based on the concept of environmental protection and multi-faceted material performance, the composite film was fabricated using water as the solvent, incorporating high elasticity of natural rubber latex (NR), multi-walled carbon nanotubes (MWCNTs), and silver nanowires (AgNWs). This rubber-based composite film was subsequently subjected to hydrophobic modification through the spraying of a mixed solution of polydimethylsiloxane (PDMS) and silicon dioxide (SiO₂). Ultimately, a hydrophobic flexible NR/MWCNTs@AgNWs strain sensor was obtained, which exhibited high sensitivity (GF = 3.64), excellent linearity (R² = 0.99), a broad monitoring range (0–200 %), rapid response capability (128 ms), and good durability (10,000 s cycles). More importantly, due to the photothermal conversion properties of MWCNTs and AgNWs, this hydrophobic flexible sensor is not only used for human motion monitoring and underwater sensing, but also has broad application prospects in optical heating in cold environments and thermal therapy for human joint diseases. This design has opened up a new path for the development of multifunctional wearable devices.