Continuous Flow Microfluidic Demixing of Electrolytes by Induced Charge Electrokinetics in Structured Electrode Arrays

A continuous flow microfluidic demixing process is realized. It utilizes high external electrical fields that are applied over electrically floating noble metal electrodes in an otherwise straight microchannel. The process converts axial electrical potential gradients into lateral molecular selective transport via a structure oriented ensemble of numerous electrodes. While the individual electrodes locally modify the electrolyte distribution by nonlinear electrokinetic effects and concentration polarization, the directed orientation of the electrode array combines the individual polarization zones to a dedicated molecular enrichment against the generated concentration gradient. A homogeneously concentrated electrolyte can be separated into arbitrarily shaped laminae of increased and depleted concentration by the presented microfluidic demixer.