Charge injection in dielectric films during electrowetting actuation under direct current voltage

Electrowetting-on-dielectric technology suffers from a lack of accuracy and reliability under DC voltage. The root of this phenomenon is related to charge injection within dielectric materials polarized and in contact with electrolytes. Correlation between contact angle measurements and transient current is used to investigate electrowetting stability under DC voltage. In particular, nature of ionic species and polarization effect are scrutinized. Asymmetric mechanisms appear between positive and negative polarizations from both wetting stability and leakage current, attributed to charge injection and allowing electrets-type actuation. A first occurrence of large amplitude reverse electrowetting is also observed.