A Wettability Switchable Surface Driven by Electrostatic Induced Surface Morphology Change Without Energy Interference On Reagents in Droplets

A novel surface wettability switchable device was successfully demonstrated by changing the surface morphology to induce contact angle change. The surface morphology transformation carried out from the deflection of thin PDMS membrane, driven by electrostatic force, can dynamically change the surface contact angle from 131 ° to 152 ° based on the contact area variation. The electrostatic energy can be throughout shielded out from droplets thanks to ground shielding effect. Since there is no direct physical or chemical (thermal, electrical, UV light etc.) interference from this actuation mean to biological solutions, the proposed method has great potential on microscale droplet transportation and is suitable to many applications especially digital fluidic systems.