Electrowetting diminishes contact line friction in molecular wetting

We use large-scale molecular dynamics to study dynamics at the three-phase\ncontact line in electrowetting of water and electrolytes on no-slip substrates.\nUnder the applied electrostatic potential the line friction at the contact line\nis diminished. The effect is consistent for droplets of different sizes as well\nas for both pure water and electrolyte solution droplets. We analyze the\nelectric field at the contact line to show how it assists ions and dipolar\nmolecules to advance the contact line. Without an electric field, the\ninteraction between a substrate and a liquid has a very short range, mostly\naffecting the bottom, immobilized layer of liquid molecules which leads to high\nfriction since mobile molecules are not pulled towards the surface. In\nelectrowetting, the electric field attracts charged and polar molecules over a\nlonger range which diminishes the friction.\n