Contact angle hysteresis due to electric inhomogeneity of topographical patterning of dielectric layer in electrowetting

Despite the crucial role of contact angle hysteresis (CAH) in various industrial processes, there is a lack of approaches to the dynamic modulation of CAH. Herein, dielectric layers in electrowetting systems are fabricated with long-range and low-magnitude topographical patterning of the dielectric layer to generate an inhomogeneous electric field at the solid-liquid interface. Reversible and dynamic modulation of CAH is implemented while avoiding possible liquid pinning. The outcome of this work enables the programming of CAH and expands its application in the modulation of solid-liquid interactions. [Display omitted] •Topological patterning in electrowetting generate inhomogeneous electric fields at the solid-liquid interface.•The inhomogeneous electric fields are incorporated into the celebrated Lippmann-Young equation.•The long-range and low-magnitude features of the patterning avoid the liquid pinning.•The contact angle hysteresis is modulated dynamically, continuously, and reversibly.