In addition, project B4 explores novel concepts of species separation by transient sieves, which are likely to excite experimental activities in the second funding period.

The first novel concept for species separation we are exploring is based on conical nanopores with gate electrodes energized by an AC voltage. In such pores, species separation should become possible by exploiting a competition between advective and diffusive transport. The second novel concept is based on the observation that in an electrolyte with anions and cations of different electrophoretic mobilities, electrodes energized with an AC voltage of zero time average can produce a non-vanishing, time averaged electric field in the electrolyte. We are exploring to what extent the emerging electric field can serve as a potential barrier that can be used for species separation. Last but not least, we are building a model related to the experimental activities of project A1, focusing on species transfer through ping-pong droplets.

The image shows an electrolyte-filled conical nanopore whose walls serve as a gate electrode, energized with an AC voltage. The arrows in the cutting plane indicate the flow field, while the colormap indicates the induced charge density.