Long working range mercury droplet actuation

This paper reports novel mercury droplet actuators with a long working range. The actuators were designed so that they can be used as thermal switches. Two types of actuation electrode were investigated: electrowetting type and electrostatic type. It was confirmed that the actuation of a mercury droplet was possible with each electrode. In addition, two types of actuator surface were investigated: flat surface and surface with micropillars. The micropillars showed considerable mobility enhancement of the droplet, but were found to be useful only with an appropriate electrode design. When the mercury droplet was actuated by 100-300 Vp-p, the observed maximum working range was about 200 mu m, which is much longer than the values reported previously. Poor repeatability of droplet motion due to the charge-up of the actuator surface was revealed as a problem.