A highly stretchable strain-insensitive temperature sensor exploits the Seebeck effect in nanoparticle-based printed circuits

Stretchable temperature sensors are critical components in soft robotics. Most existing temperature-sensing technologies feature a strong coupling between the response to temperature and response to deformation of the measured object, resulting in strain-polluted temperature measurements. Here we leverage the Seebeck effect in nanoparticle-based printed circuits. Using nanoparticle-based circuits as conductive wires provides stretchability. While a resistive measurement is highly perturbed by strain variations, using a Seebeck-induced change in the voltage ensures that the measured signal is insensitive to strain. Two nano-structured wires made of different materials are printed and embedded in a soft polymeric film to form a micro-thermocouple. This temperature sensor shows good stretchability up to 40% strain, high linearity of response, and excellent repeatability between different samples.