A novel intrinsically strain sensor for large strain detection

Soft and stretchable electronic devices play an important role in the growing fields of “soft robotics”, electronic skin, prosthetics, etc. As one of the fundamental units for stretchable electronics, strain sensors have been widely investigated in previous studies, although large strain detection is still a well-known challenge. Intrinsically stretchable sensor could undergo large strain depending on the stretchable matrix, and have attracted lots of attentions in recent years. In this study, we introduce liquid metal into the volumetric matrix of the flexible substrates to construct a novel intrinsically strain sensor, which could undergo large strain of the flexible substrates, avoiding the conventional fracture failures at the interfaces of the sensor and the substrate. Due to the advantages of the extremely stretchable ability, intrinsically strain sensors, i.e., elongation sensor and bending sensor, are further developed. It shows that, up to 178% strain could be measured by these stretchable sensors, and 74 m−1 of curvature for the bending sensor. The proposed sensors also show excellent responses, less than 120 ms for steady, and without delay and flushness. The proposed intrinsically strain sensor provides an alternative way to construct new types of intelligent flexible electronics and artificial skins.