Characterization of electrowetting, contact angle hysteresis, and adhesion on digital microfluidic devices with inkjet-printed electrodes

This investigation characterizes electrowetting performance, contact angle hysteresis, contact line pinning force, and adhesion work on digital microfluidic devices with inkjet-printed electrodes. It also demonstrates electrowetting-induced droplet detachment on these devices. Average performance was similar to cleanroom-fabricated devices in all experimental measurements, but variability was persistently higher on inkjet-printed devices. This appears to be consistent with increased defect density and variation in local electrowetting number caused by increased roughness of printed electrodes. This work suggests that inkjet-printed devices are suitable for the study of colloidal transport and deposition under electric fields and electrowetting-induced droplet detachment when accompanied by rigorous uncertainty analysis.