Poly(ε-caprolactone)–Ionic Liquid Composite as Piezoionic Mechanical Sensor

In recent years, the issue related to electronic waste production has been gaining prominence. One of the approaches considered to limit the impact of e-waste on the environment involves the development of biodegradable electronic devices or devices that dissolve in the environment at the end of their life cycle. In this study, we present the preliminary results related to the creation of a sensor that could meet both criteria. The device was constructed using a composite material obtained by impregnating a membrane of polycaprolactone (a biodegradable polymer) with 1-Ethyl-3-Methylimidazolium tetrafluoroborate (a water-soluble ionic liquid), which was coated with a conductive silver-based varnish. Leveraging the piezoionic effect, the device has been proven to function as a vibration sensor with a sensitivity of approximately 1.9 × 10−5 V/mm and a resolution of about 0.15 mm.