Uncovering Molecular Mechanisms of Electrowetting and Saturation with Simulations

Jin Liu, Moran Wang, Shiyi Chen, Mark O. Robbins
2012 Physical Review Letters  
Molecular dynamics simulations are used to explore the physical mechanisms of electrowetting and the limits of continuum theories. Nanoscale drops exhibit the same behavior seen in macroscopic experiments: The contact angle θ follows continuum theory at low voltages and then saturates. Saturation limits applications of electrowetting and its origin is of great interest. In the simulations, saturation occurs when ions are pulled from the drop by large local fields. Saturation can be controlled
more » ... can be controlled by changing temperature, screening or the energy binding ions to the fluid. We show a local force balance equation for θ remains valid even after saturation and that the interface approaches the equilibrium contact angle within a few nanometers of the solid.
doi:10.1103/physrevlett.108.216101 pmid:23003282 fatcat:x5ano2dksbg2zb73wspljvvxbe