We will report two new classes of engineered soft polymeric architectures that undergo complex reconfiguration and shape change in magnetic fields. These structures were made possible by advances in the engineering of directional interactions, of flexible inter-particle bonds, and of means for 3D printing with ultrasoft silicone. In the first part of the talk, we will discuss how complex magnetic polarization patterns of metallo-dielectric microcubes lead to multidirectional interactions and assembly of reconfigurable microclusters. These sequence-encoded clusters can be reversibly actuated and spatially transported by magnetic fields and can be designed to be self-motile in non-Newtonian media. In the second part of the talk, we will describe new types of magnetoactive soft silicone architectures fabricated by 3D printing. We formulated new multiphasic gels for 3D printing consisting of polydimethylsiloxane (PDMS) microbeads, liquid PDMS and water. Owing to the capillary binding, these Homocomposite Thixotropic Pastes (HTPs) can be easily extruded and shaped. HTPs containing iron microparticles enabled the development of a new class of versatile 3D-printed magnetic architectures. They can be actuated by means of normal magnetophoretic force, mediated by capillarity, while floating on water. By engineering the pattern of 3D-printed filaments we designed isotropic and anisotropic auxetic meshes, motile structures and actuators. Such soft magneto-active structures that are programmed to reconfigure under magnetic field could serve as active tissue scaffolds and soft robots mimicking creatures that move on water surfaces.

Microscale engineering of magnetically actuated, reconfigurable and motile soft polymeric architectures

2019 Spring National Meeting

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