(609f) Surface Forces Caused by Capillary Adhesion and Electrowetting

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, vapor pressure, and applied potential. Our measurements are complemented by dynamic contact angle measurements, impedance spectroscopy, and X-ray photoelectron spectroscopy. We compare our result to the Kelvin equation modified for an external applied potential.