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

Abstract 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.