AC and DC voltage electrowetting on ferroelectric polymer for low voltage applications Available to Purchase

We demonstrate ac and dc voltage electrowetting (EW) on bilayer dielectric. It consists of thick layer of ferroelectric polymer, polyvinylidene fluoride-co-hexaflouropropylene (PVDF-HFP) and a nanometer thin layer of hydrophobic Teflon AF over it. The ferroelectric layer increases the effective dielectric constant of the bilayer geometry; however it introduces remnance polarization in the system resulting in pinned EW response. The reverse voltage needed to unpin this state depends on the magnitude of applied voltage. Also dc-voltage EW response is asymmetric, higher response is seen for positive polarity to the droplet. This is likely to be attributed to the intrinsic charge trapping by hydrophobic polymer layer upon exposure to the ambient air. The EW response for ac-voltage shows distinct behavior, which varies with frequency of applied voltage. The maximum EW response is observed for 1 kHz driving frequency. The study demonstrates that dc-voltage EW exhibits hysteretic response in contact angle change. Ac-voltage shows highest response due to the maximum dielectric constant of bilayer useful in low voltage ac EW application.