The separation of suspended particles smaller than 1 µm regarding their conductivity and shape is an unresolved task especially with a high throughput that is relevant for industrial applications. Possible technology fields range from processing of valuable sludges to innovative semiconductors. To enable this, electrodeless dielectrophoretic (iDEP) filtration will be used as a separation method in this project.
Multidimensional separation of particles can be achieved by adjusting the field frequency and field strength considering both the deposition and the subsequent remobilization of the particles. The mechanism of the iDEP filter is based on the polarization of the target particles, which depends on the medium and particles properties. In combination with a non-uniform electric field induced by dielectrical insulating posts a dielectrophoretic force appears, that selectively retards particles. Perspectively, fibreglass membranes can assume the function of the insulating posts. In this project, we are modelling the switchable, sorting filter by a geometrically defined microfluidic channel with an array of insulating posts superimposed by an alternating electric field. By means of experimental investigations with this structure, we expect to understand how well the separation efficiency with regard to conductivity and shape of the particles can be predicted from the retention of unmixed particles. We also want to investigate whether it is possible to achieve high separation rates even with particles smaller than 100 nm. The newly gained process understanding should enable to recognize the influence of geometry and process parameters for a later upscaling. The project is integrated into the DFG priority programme No. 2045 „MehrDimPart - Hochspezifische mehrdimensionale Fraktionierung von technischen Feinstpartikelsystemen“.