Abstract
This paper describes the evaluation of friction force between liquid droplets and solid surfaces in electrowetting devices. The friction of droplets has a significant effect on the performance of the electrowetting-based droplet manipulation and conveyor systems. The conveyor plates with various microstructured surfaces were fabricated using MEMS techniques. Each plate was placed in contact with a water droplet actuated by EWOD (Electrowetting-on-dielectric) and the friction force was measured using a double-cantilever spring. The results show that the plate with pillar structures exhibits high friction, while the plate with cone structures shows very low friction. Furthermore, experiments for conveying these plates using EWOD actuation were carried out. The plate with high friction was found to be transported effectively by EWOD actuation.
