High Content Ionic Liquid Microdroplet-Filled Elastomers with Dielectric Stability for Epidermal Electronics

Ionic conductor-based stretchable sensors are frequently adopted for epidermal electronics, but they are sensitive to changes in the surrounding temperature and humidity, resulting in unstable electrical performance. Here, we prepared a series of high-volume-content ionic liquid filled elastomers (ILE). A volume filling content of 50% (ILE 50%) was obtained, resulting in a significant improvement of the dielectric constant from 3.0 to 22.1 at 100 kHz, and the softness of the composite was perfectly preserved, which is beneficial to preparing high-performance capacitive stretchable sensors. At the same time, ILE can maintain good dielectric properties under multiple large deformations (50%) as well as temperature changes (−20 to 80 °C) and a high humidity (66% RH to 99% RH) environment, showing good mechanical and environmental stability. This strategy provides ideas for the development of reliable epidermal electronics.