Design and fabrication of magnetically tunable microstructured surfaces

In this work, we present a novel fabrication process for the development of magnetically tunable micropillar arrays, where the tilt angle is controlled with an applied magnetic field. The nickel pillar arrays were fabricated by electroplating and transferring onto a PDMS surface. With a field strength of 0.5 Tesla and a field angle of 60°, a uniform 10.5° tilt angle of the pillar arrays was achieved. Furthermore, we developed a model to capture the tilt angle as a function of the magnetic field, and showed that by replacing nickel to cobalt, the tilt angle could be increased to 30° with the same field. This work promises tunable surface designs for important device platforms in microfluidics, biological and optical applications.