Recently, the demand for wearable sensors is growing due to their ability to help monitor motion and provide clinically relevant data for healthcare. Commonly these sensors detect strain through their resistance change during deformation. However, they generally exhibit a negative piezoconductive property, that is, their conductivity decreases when stretched. This causes high resistance under stretching, limiting their applications in highly stretchable electronics. In this work, we report two positive piezoconductive composites with different polymer matrices and shapes of metal particles: liquid metal magnetorheological elastomers filled with iron microparticles (Fe-LMMRE) and sea urchin-like nickel microparticles (Ni-LMMRE), respectively. These two LMMREs both exhibit a sharp decrease in resistance when stretched, indicating the unconventional positive piezoconductive property. As a highly flexible, sensitive strain sensor for detecting human motions with a gauge factor of 100 and a fracture strain of 203%, the Ni-LMMRE is used to develop a portable and wearable sign language communication device with a comprehensive, programmable, and configurable input and output system to help people express sentences precisely without speaking.
Recently, the demand for wearable sensors is growing due to their ability to help monitor motion and provide clinically relevant data for healthcare. Commonly these sensors detect strain through their resistance change during deformation. However, they generally exhibit a negative piezoconductive property, that is, their conductivity decreases when stretched. This causes high resistance under stretching, limiting their applications in highly stretchable electronics. In this work, we report two positive piezoconductive composites with different polymer matrices and shapes of metal particles: liquid metal magnetorheological elastomers filled with iron microparticles (Fe-LMMRE) and sea urchin-like nickel microparticles (Ni-LMMRE), respectively. These two LMMREs both exhibit a sharp decrease in resistance when stretched, indicating the unconventional positive piezoconductive property. As a highly flexible, sensitive strain sensor for detecting human motions with a gauge factor of 100 and a fracture strain of 203%, the Ni-LMMRE is used to develop a portable and wearable sign language communication device with a comprehensive, programmable, and configurable input and output system to help people express sentences precisely without speaking.
 

liquid metal, magnetorheological elastomer, sensing scapability, piezoelectric resistence