Abstract

With sizes not exceeding a few centimetres and usage ranging from blood sample analysis to cooling devices and integrated circuit components (and far beyond), liquid systems at small scales play an indispensable part in our lives. Their production and maintenance however is a highly sensitive and expensive process. This body of research focuses on eliminating these drawbacks by creating efficient mechanisms that do not use any moving parts and do not require the presence of an oncoming flow.

We analyse electrostatic control procedures in simple geometrical configurations, such as channels containing layers of immiscible fluids. Stability theory guides the imposition of voltage distributions that efficiently manipulate the fluid-fluid interface and harness the classical instabilities arising in such systems. We then formulate nonlinear asymptotic models that enable the study of the interfacial motion far beyond the level of small perturbations. Finally, we implement state-of-the-art computational tools based on the volume-of-fluid method in both two- and three-dimensional contexts to steer these arguments towards practical applications involving microfluidic mixing, pumping and directed polymer assembly.