Stretch-Tolerant Waterproof and Self-cleaning CBNPs/Graphene Strain Sensor for Multifunctional Applications

Wearable strain sensors are widely used in bionic robots and wearable electronic devices. However, such devices inevitably work in degradative environments such as under wet conditions and contaminants, deteriorating the sensing performance and stability. In this work, a stretch-tolerant superhydrophobic, self-cleaning graphene-based strain sensor with high sensitivity, is reported using prestretching strategy. The stretch-tolerant superhydrophobic surface of the sensor is prepared by attaching carbon black nanoparticles to the Ecoflex substrate for constructing surface roughness and modifying with polydimethylsiloxane for achieving low surface energy under stretched condition (50% strain), which endow the sensors with an outstanding self-cleaning performance for various contaminants. Moreover, the sensor retains excellent super-hydrophobicity even under stretching. The sensor is also insensitive to common liquids in daily life including water, such as tea, milk, and coffee. Furthermore, the proposed strain sensor achieves wide sensing ranges (strain over 100%) and has a superior sensitivity (gauge factor up to 653.4 at 90% stretching), which shows great promising in accurate human motions monitoring both in the air and underwater. Besides, by placing the strain sensor on a bridge, the number of vehicles on the bridge can be detected, which exhibits an ideal platform for real-time traffic flow monitoring.