Purpose – Digital microfluidic devices have been demonstrated to have great potential for a wide range of
applications. These devices need expensive photolithography process and clean room facilities, while printed
circuit board (PCB) technology provides high configurability and at low cost. This study aims to investigate
the mechanism of electrowetting-on-a-dielectric (EWOD) on PCB by solving the multiphysics interaction
between fluid droplet and electric field. The performance of system will be improved by inducing an efficient
electric field inside the droplet.
Design/methodology/approach – To induce an electric field inside the droplet on a PCB and change the
initial contact angle, the mechanism of EWOD is studied based on energy minimization method and a set of
simulations are carried out by considering multiphysics interaction between the fluid droplet and external
electric field. The performance of EWOD on a PCB system is investigated using different electrode structures.
Findings – Surface tension plays an efficient role in smaller sizes and can be used to move and control a
fluid droplet on a surface by changing the interfacial surface tension. EWOD on a PCB system is studied. and
it revealed that any change in electric field affects the droplet contact angle and as a result droplet deformation
and movement. The electrode pattern is an important parameter which could change the electric potential
distribution inside the droplet. Array of electrodes with square, zigzag interdigitated and crescent shapes are
studied to enhance the EWOD force on a PCB substrate. Based on the results, the radial shape of the crescent
electrodes keeps almost the same actuated contact line, applies uniform force on the droplet periphery and
prevents the droplet from large deformation. A droplet velocity of 0.6 mm/s is achieved by exciting the
crescent electrodes at 315 V. Furthermore, the behavior of system is characterized for process parameters such
as actuation voltage, dielec