Tough, Bio‐disintegrable and Stretchable Substrate Reinforced with Nanofibers for Transient Wearable Electronics

Abstract Research on transient wearable electronics with stretchable components is of increasing interest because of their abilities to conform seamlessly to human tissues and, more interestingly, disappear from the environment when disposed. To wear them comfortably, their component materials must be pliable, tough, stretchable, biocompatible, and disintegrable. However, most biodegradable materials are not stretchable or tough, limiting their use in transient wearable electronics. Herein, these challenges are addressed by demonstrating a biodegradable nanofiber (NF)‐reinforced water‐borne polyurethane (NFR‐WPU) with stretchability, toughness, and partial biodegradability by embedding biodegradable composite NFs of poly(glycerol sebacate): poly(vinyl alcohol) (PGS:PVA) into the WPU matrix, thus rendering its properties tunable. An optimal loading amount of NFs into the NFR‐WPU significantly enhanced the toughness by 19 times while maintaining the Young's modulus as low as 3.3 MPa. Furthermore, the NFR‐WPU substrate has very high fracture toughness and shows excellent biocompatibility. Moreover, the NFR‐WPU has a disintegration rate nine times greater than that of pristine WPU. Finally, disintegrable and stretchable triboelectric and capacitive touch sensors on the NFR‐WPU are fabricated and demonstrated for potential use in transient wearable electronics.