Biomimetic magnetic-responsive cilia-like soft device: surface energy control and external field actuation

Many natural systems that are capable of self-regulated, autonomous controlling their shapes, generally match or even exceed the performance of rigid robotic systems. Currently, designing biomimetic soft devices by mimicking the natural intelligence with tunable ability still remains a grand challenge. Herein, we demonstrate a novel biomimetic cilia-like soft device using the magnetic feedback of microrod arrays. Such cilia-like microrod arrays are fabricated by distributing Co nanoparticles into silicon-based polymer. The critical aspect ratio of the microrod arrays can reach 48.7, which is 5.4-times higher than original 9.1 through considerably reducing its surface energy. This large increase in critical aspect ratio will endow the microrods an excellent durability and ensure the posture recovery during the magnate-responsive actuation. Meanwhile, magnetic-responsive Co nanoparticles are aligned and concentrated in the top of each microrod, which leads to the differentiated elastic modulus and ultimate strength along the length. Thereby, as the magnetic field intensity increases, the microrod arrays autonomously perform correspondingly reversible bending deformation without collapse, successfully achieving remotely controlled magnetic actuation. Therefore, this work opens up a new avenue towards soft, autonomous smart devices.