Electrowetting of Room Temperature Ionic Liquids (RTILs) for Capillary Force Manipulation

The feasibility of using room temperature ionic liquids (RTILs) as the electrowetting liquid for capillary force microgrippers was studied. The non-volatility and thermal stability of ionic liquids make them suitable for droplet based microgripping application in high temperature and vacuum environments. Electrowetting on co-planar electrodes was utilized to dynamically change the contact angle of a 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) liquid bridge to control the capillary lifting forces. The lifting force generated by the liquid bridge was experimentally characterized. The maximum capillary force was 146μN. The dynamic response of the BmimPF6 liquid bridge was also characterized.