Spatial hetero-structured composites with ultrawide linear range for positive-negative pressure sensing and e-skin of bionic fish

For impelling practical applications of flexible sensors or electronic skins, it is challenging and urgent to fabricate multifunctional flexible mechanical sensors with good linearity over a wide working range in an economical and scalable manner. Currently, it is immensely difficult to simultaneously detect tension, pressure and bending with high linearity over a wide strain range by using one film without sensor integration. Herein, we present a porous flexible mechanical sensor with a spatial electron transport network consisting of ethylene-α-octene random copolymer (ORC) elastic skeleton with surface embedded carbon black (CB) and carbon fiber (CF) bridges. Such an interesting spatial hetero-structure can shunt the electron transport effectively to regulate the resistance change of the sensor during strain loading, resulting in linear electrical signal response to mechanical deformation for a tensile strain up to 320% and a pressure up to 1.3 MPa, as well as a bending angle ranging from -90o to 90o, respectively. Besides, it shows the detection capability of ambient pressure ranging from -0.09 MPa to 0.4 MPa continuously. Such a multifunctional film sensor with ultrawide linear working range demonstrates potential applications for monitoring body motions of athletics and underwater soft robots.