Ion selective gates: active device component for 3D microfluidic architecture

This thesis describes the development of porous ion-transport oxide interconnects that allow molecular communication between microchannels in complex microfluidic architectures. New methods to control the permeability of interconnects to certain species by externally tuneable parameters was investigated. DC electric fields were used to impose a driving force for the transport of selected cationic and anionic species. Electric fields are preferred over pressure gradients in nanochannels, because very large pressure drops are required to drive flow in small channels, while typical operating voltages are below the potential difference required for decomposition of water. Applying an external electric field across the interconnects, a potential difference is created across the membrane, which makes it is possible to selectively drive charged species from one liquid into the other through interconnects, by means of ion migration, Fick diffusion and/or electroosmotic flow.