Stretchable strain and temperature sensor based on fibrous polyurethane film saturated with ionic liquid

Stretchable strain sensor and temperature sensor are two essential components for the integration of wearable electronics and electrical skins, which have great potentials in healthcare monitoring, human motion monitoring and human-machine interfaces. Up to now, it is still a challenge to fabricate the stretchable and multifunctional sensor with both the capabilities of strain sensing and temperature sensing by an effective and economical method. Herein, a simple route is provided to design multifunctional sensors with high sensing performances for strain and temperature, which combines the electrospun technique and ultrasonication anchoring technique. Specifically, fibrous thermoplastic polyurethane (TPU) film is fabricated by electrospun technique at first, and then is saturated by ionic liquid (IL) to design the stretchable sensor. Attributed to the stable response and fast reconstruction of conductive pathways of ionic liquid under the stretching-releasing process, the TPU/IL sensor can serve as strain sensor, which exhibits various merits, including fast response time of 67 ms, ultra-low detection limit (0.1%), ultra-wide sensing range from 0.1% to 400% and excellent durability for long-term usage. In addition, it is noteworthy that TPU/IL sensor has great advantages in temperature sensing, which possesses a lowest temperature accuracy of 0.5 °C. This work provides a novel route for manufacturing stretchable multifunctional sensor with both temperature and strain sensing functions, which may accelerate the development of the emerging wearable electronics and electrical skins.