Development and testing of a synchronous micropump based on electroplated coils and microfabricated polymer magnets

Abstract

In this paper, the concept, fabrication, activation and testing of a novel synchronous micropump based on microfabricated copper coils and polymer magnets are presented. The pump works by the synchronized rotation of two polymer magnets in an annular SU-8 microfluidic channel. Magnet rotation is achieved by sequentially activating a set of planar coils to repel or attract the first magnet (traveling magnet) through the channel, while the second one is anchored between the inlet and the outlet ports. At the end of each pumping cycle, the magnets exchange their anchored and traveling functions. The synchronization of magnet rotation has been achieved through programming two activation schemes that proved the high dependence of the pump operation and performance on employed activation scheme parameters. The magnetic forces exerted from electroplated coils on the polymer magnet were tested experimentally using a three-dimensional force sensor. Different coil dimensions have been investigated. A maximum force of 658 µN at an applied current of 138 mA was achieved. The micropump has successfully pumped water with rotational speeds up to 83.33 rpm. Water flow rates in the range of 17.3 µL min−1 at 31.25 rpm to 158.7 µL min−1 at 83.33 rpm were achieved.