(207c) Electrowetting in a Nanopore Via Capillary Condensation

Frechette, J., Johns Hopkins University
Gupta, R., Johns Hopkins University

Electrowetting is an effective means to move liquid droplets inside a micro/nanofluidic device. In this talk we will show how we can implement and characterize nanoscale electrowetting in the Surface Forces Apparatus (SFA). Using the SFA, we measured capillary adhesion between hydrophobic surfaces in the presence of condensable vapors. We characterized how adhesion depends on surface chemistry and partial pressure and compared our results with that predicted from the Kelvin equation. We have also modified the SFA to allow for external potential control and have investigated and characterized how we can favor the condensation of undersaturated water vapors on hydrophobic surfaces by charging the hydrophobic surface. We compare our measurements with predictions from the Young-Lippmann-Kelvin equation. Our measurements are complemented by dynamic contact angle and macroscopic electrowetting measurements.