User-Interactive Thermotherapeutic Electronic Skin Based on Stretchable Thermochromic Strain Sensor

User-interactive electronic skin (e-skin) with a distinguishable output has enormous potential for human-machine interfaces and healthcare applications. Despite advances in user-interactive e-skins, advances in visual user-interactive therapeutic e-skins remain rare. Here, a user-interactive thermotherapeutic device is reported that is fabricated by combining thermochromic composites and stretchable strain sensors consisting of strain-responsive silver nanowire networks on surface energy-patterned microwrinkles. Both the color and heat of the device are easily controlled through electrical resistance variation induced by applied mechanical strain. The resulting monolithic device exhibits substantial changes in optical reflectance and temperature with durability, rapid response, high stretchability, and linear sensitivity. The approach enables a low-expertise route to fabricating dynamic interactive thermotherapeutic e-skins that can be used to effectively rehabilitate injured connective tissues as well as to prevent skin burns by simultaneously accommodating stretching, providing heat, and exhibiting a color change.