Active control of surface profile by magnetic micropillar arrays

Abstract

Abstract Pillar arrays have been extensively used in science and engineering, with major applications at the micro or nano scale, requiring a control technique that can operate in a small, confined area. In this study, an active control method for the surface profile was developed using elastic micropillar arrays with magnetic tips. Single-, double-, and multiple-magnetic pillar arrays were fabricated from poly(dimethylsiloxane) and carbonyl iron particles using a mould prepared by laser drilling. The pillar behaviour was investigated in static and moving magnetic fields. In a static magnetic field, a single pillar is bent, double pillars are attached to a pair, and multiple pillars form pair and line patterns parallel to the magnetic field direction at a field strength of 55 mT and 85 mT, respectively, for a horizontal magnetic field. In a moving magnetic field, the propagating deformation of pillar arrays could successfully transport an 8 mm diameter plastic bead horizontally across the pillared surface at a speed of 4 mm s−1.