Biodegradable stretchable electronics have demonstrated great potential for future applications in stretchable electronics and can be resorbed, dissolved, and disintegrated in the environment. Most biodegradable electronic devices have used flexible biodegradable materials, which have limited conformality in wearable and implantable devices. Here, we report a biodegradable, biocompatible, and stretchable composite microfiber of poly(glycerol sebacate) (PGS) and polyvinyl alcohol (PVA) for transient stretchable device applications. Compositing high-strength PVA with stretchable and biodegradable PGS with poor processability, formability, and mechanical strength overcomes the limits of pure PGS. As an application, the stretchable microfiber-based strain sensor developed by the incorporation of Au nanoparticles (AuNPs) into a composite microfiber showed stable current response under cyclic and dynamic stretching at 30% strain. The sensor also showed the ability to monitor the strain produced by tapping, bending, and stretching of the finger, knee, and esophagus. The biodegradable and stretchable composite materials of PGS with additive PVA have great potential for use in transient and environmentally friendly stretchable electronics with reduced environmental footprint.

The development of wearable electronics with stretchable components that can conform seamlessly to human tissues and eventually disappear from the environment when disposed is of increasing interest. The challenge is to create materials that are pliable, tough, stretchable, biocompatible, and disintegrable. Biodegradable materials are promising for this purpose, but most of them are not stretchable or tough enough for use in transient wearable electronics. To address these challenges, we present a novel approach to create biodegradable nanofiber-reinforced water-borne polyurethane (NFR-WPU) with stretchability, toughness, and partial biodegradability. This is achieved by embedding biodegradable composite nanofibers (NFs) of poly(glycerol sebacate):poly(vinyl alcohol) (PGS:PVA) into the WPU matrix, which renders its properties tunable. We optimized the loading amount of NFs into the NFR-WPU and found that it significantly enhanced the toughness by 19 times while maintaining the Young's modulus as low as 3.3 MPa. Moreover, the NFR-WPU substrate has very high fracture toughness and shows excellent biocompatibility. It also has a disintegration rate nine times greater than that of pristine WPU. We fabricated and demonstrated disintegrable and stretchable triboelectric and capacitive touch sensors on the NFR-WPU, which have potential use in transient wearable electronics. In summary, our study offers a promising approach for developing transient wearable electronics with stretchable and biodegradable materials. Our NFR-WPU material has excellent mechanical properties, biocompatibility, and disintegration rate, and our disintegrable and stretchable sensors show great potential for future applications.