RESUMO
A polydimethylsiloxane ( PDMS )/glass microfluidic chip consisting of a three-layer sandwich structure and three-parallel micro-electrode system was fabricated for the separation of polystyrene microspheres according to the particle size in high conductive solution by electric field produced by alternating current. The principle of electrokinetics of microspheres directional movement was investigated. The results showed that, when the applied voltage was 14 V at 100 kHz, the separation efficiency of 10 and 25 μm polystyrene microspheres was the best. Similarly, with a voltage of 10 V at 2 MHz, the separation efficiency of 5 and 25 μm polystyrene microspheres could achieve the highest value. Meanwhile, the voltage of 11 V at 1 MHz was suitable for the separation of 5 , 10 and 25 μm polystyrene microspheres with the separation efficiency of over 90%. At the same time, the formation of the laminar region in the middle of the electrode gap was the key role of microsphere separation.