Thermochromic and Piezocapacitive Flexible Sensor Array by Combining Composite Elastomer Dielectrics and Transparent Ionic Hydrogel Electrodes

Electronic skin (e‐skin) is an important building block to achieve human–machine interfaces, functional prostheses, and health monitoring devices. While high pressure and temperature sensitivity with visible indication are important for e‐skins, such multifunctionality often requires complex fabrication and integration processes, which hinders practical applications. Here, a simple solution is shown to fabricate a bimodal e‐skin sensor array that is capable of changing color as a response to a range of temperatures (26–40 °C) with an ability to sense finger tap (≈20 kPa pressure) as a pressure sensor. The bimodal functionality of thermochromic response and tactile sensing is achieved by judicial material selection of our custom‐developed elastomer composite containing thermochromic dye, which is sandwiched by tough and transparent stretchable electrodes of ion‐containing polyampholyte hydrogels. The e‐skin array is potentially promising for applications in internet‐of‐things and soft robotics.