Locally Reprogrammable Magnetic Micropillars with On-Demand Reconfiguration and Multi-Functionality

Magnetic micropillars have shown great promise in various applications including information storage, fluid manipulation, and soft robotics. But to date, magnetic micropillars with reprogrammable magnetization, multi-modal deformation and functionality, and on-demand fast actuation have not been reported yet. Herein, locally reprogrammable ferromagnetic micropillars with on-demand reconfiguration and multi-functionality are reported. The magnetic micropillars are fabricated by dispersing CrO 2 microparticles (diameter ≈5 µm, Curie temperature T c = 110 °C) in the Ecoflex matrix. The magnetization of each micropillar can be easily programmed and reprogrammed by simultaneously heating the micropillar above T c via laser and applying a magnetizing field. The magnetization can be programmed as omnidirectional in three dimensions, thus entire magnetic micropillar arrays show a variety of deformation modes (including both synchronous and asynchronous modes) with on-demand fast actuation by remotely applying magnetic fields. Four representative functionalities of the magnetic micropillars are demonstrated: information encryption, particle pumping, ink mixing, and underwater crawling robot.