Test structures and a measurement system for characterising the lifetime of EWOD devices

This paper presents a methodology together with a characterisation system for rapidly and quantitatively evaluating the lifetime and reliability of Electro-Wetting-on-Dielectric (EWOD) microfluidic devices. By studying the contact angle (CA) change when electrowetting forces are applied on the test structure, the number of times of a droplet can be switched between relaxed and actuated states can be characterised. This paper describes the development of an automated measurement system together with test structures designed to quickly characterise and optimise EWOD dielectric layer compositions. This enables the rapid determination of the driving voltage that results in the longest lifetime of the device, providing the tools to optimise both the process, architecture and the voltage driving scheme.