Super soft but strong E-Skin based on carbon fiber/carbon black/silicone composite: Truly mimicking tactile sensing and mechanical behavior of human skin

Besides the prominent tactile sensing ability, human skin is also well known for its unique mechanical behavior combination of excellent softness with certain stretchability of a strain-limiting effect to prevent damage from excessive strain. Here a stretchable e-skin truly mimicking the tactile sensing and mechanical behavior of human skin is fabricated. Carbon black (CB)/silicone composite with excellent piezo-resistive performance is employed as mechanical stimuli sensing material, which provides super softness, large stretchability, high strain sensitivity and long-term reliability for the e-skin. High performance carbon fiber (CF) with quasi-sinusoidal shape is designed to serve as electrode material and reinforcement filler simultaneously, which renders the e-skin a typical J-shape stress-strain curve similar as that of human skin. The Young's modulus, tensile strength and failure strain of the e-skin can be readily adjusted by controlling the content and shape of the CF electrode to match them well with those of human skin. Finally, the fabricated e-skin exhibits the capability of spatiotemporal recognition of the location and magnitude of contact forces in monitoring dynamic stress distribution. The as-prepared stretchable e-skin based on CF/CB/silicone composite is highly promising for robotics and prosthetics, etc.