Intrinsically stretchable, transient conductors from a composite material of Ag flakes and gelatin hydrogel.

Transient conductors are one of the most important parts in transient electronics, which attract great attentions due to their environmental friendly and bio-compatible characters. To meet the requirement for wearable electronics, a good stretchability and mechanical durability are needed for the transient conductors. However, it remains challenging to achieve stretchability and transient behavior simultaneously due to a lack of the proper elastomer. Here, we demonstrate the first highly stretchable and transient conductor from a composite material of Ag flakes and gelatin hydrogel. It shows a maximum stretchability of more than 100% with minimal resistance increase, and good cyclic durability of 1000 cycles of deformation at 20%. The above good mechanical property comes from the rational design of the conductor with a seamless interface between the hydrogel and the Ag flakes. When the conductor is immersed in water at 60°C, it can be quickly dissolved within 90 seconds, and the transient behavior can be controlled by tuning the content of the hydrogel in the conductors and dissolving temperature. These properties make the conductor as a good wiring candidate for stretchable and transient electronics.