Robust ultrasensitive stretchable sensor for wearable and high-end robotics applications

Recent applications of strain sensors such as electronic skin and human-friendly wearable sensors require the design to achieve wide-sensing range, precise reproducibility, durability, and biocompatibility. The current work proposes a robust liquid-type strain sensor based on glycerol and graphene quantum dots (Gly-GQDs) as sensing units. The fabrication process followed a simple, cost-effective, and scalable approach of molding and casting using Ecoflex-0030 with sinusoidal channel consisting of 2 mm diameter. The as-assembled device showed remarkable sensitivity with gauge factor of 10.2 at stretching of 150%, excellent linear response (COD 0.993), minimum memory effect of 1.8%, ability to track input force up to the speed of 5 Hz, the lowest possible limit of detection (1%), and stability (up to 8000 cycles) and complete structural stability towards water contact making it strong candidate for the underwater applications. Furthermore, its biocompatibility was proven using rigorous biological characterizations. Finally, the device was tested in a variety of wearable applications. Its excellent performance enables it to be a strong candidate for wearable application, if compared with other fluidic type strain sensors.