Strain-Insensitive Intrinsically Stretchable Capacitive Sensors for Tactile Applications

Intrinsically stretchable electronics are promising for wearable devices and sensors due to their compatibility with human skin's elasticity. Soft pressure sensors are crucial in fields like intelligent robotics and prosthetics. However, general soft sensors have difficulty distinguishing between strain and pressure signals, necessitating additional processing for data analysis. Here, we report on a strain-insensitive pressure sensor utilizing a dielectric elastomer with tunable dielectric properties. Our group agglomerates high dielectric constant nanoparticles into spheres within a dielectric elastomer matrix. As a result, our dielectric elastomer shows a decrease in dielectric constant as the nanoparticle clusters compress into ellipsoids when stretched. This approach can produce soft sensors that are strain-insensitive and have been used to show that there is little signal variation when standing, walking, and exercising, but that a signal appears when pressure-like falls occur. This innovation represents a significant advance in the development of stretchable capacitive pressure sensors. By overcoming the inherent challenges of pressure sensors and improving their practicality, our work provides a potential solution to distinguish between pressure and strain signals. These advances pave the way for the integration of these sensors into next-generation wearable devices, intelligent robotics, and other advanced applications.