Magnetic Multimaterial Printing for Multimodal Shape Transformation with Tunable Properties and Shiftable Mechanical Behaviors

Abstract

Magnetic soft materials (MSMs) have shown potential in soft robotics, actuators, metamaterials, and biomedical devices because they are capable of untethered, fast, and reversible shape reconfigurations as well as controllable dynamic motions under applied magnetic fields. Recently, magnetic shape memory polymers (M-SMPs) that incorporate hard magnetic particles in shape memory polymers demonstrated superior shape manipulation performance by realizing reprogrammable, untethered, fast, and reversible shape transformation and shape locking in one material system. In this work, we develop a multimaterial printing technology for the complex structural integration of MSMs and M-SMPs to explore their enhanced multimodal shape transformation and tunable properties. By cooperative thermal and magnetic actuation, we demonstrate multiple deformation modes with distinct shape configurations, which further enable active metamaterials with tunable physical properties such as sign-change Poisson's ratio. Because of the multiphysics response of the M-MSP/MSM metamaterials, one distinct feature is their capability of shifting between various global mechanical behaviors such as expansion, contraction, shear, and bending. We anticipate that the multimaterial printing technique opens new avenues for the fabrication of multifunctional magnetic materials.

Multifunctional magnetic soft composites: a review

“…Direct ink writing (DIW) printing is an extrusion-based additive manufacturing method by which materials with shear-thinning properties are extruded from printing nozzles. It is a flexible filament-by-filament printing method that serves as a tool for fabricating single or multi-material geometries, including magnetic hydrogels [ 105 ], elastomers [ 49 , 106 ], and SMPs [ 78 , 107 ] with complex structures and programmed magnetization distributions. Recent work develops a customized DIW printing system with in-situ magnetization programming capability, where the magnetizations of NdFeB particles are aligned along the extrusion direction under a localized magnetic field.…”

“…The properties and functionalities of the soft material systems are related to the configurations and deformations of the structures. With the ability to undergo large deformations as programmed, the mechanical [ 46 , 80 , 107 , 121 ], optical [ 112 , 122 ], and acoustic properties [ 120 , 123 – 127 ], or wettability [ 106 , 119 ] of magnetic soft composites are actively tunable under the applied magnetic field. For instance, an array of microplates embedded with aligned Fe microparticles possess a superhydrophobic or hydrophilic surface on each side of the plates ( figure 5(d) [ 119 ]).…”

“…Figure 5(f) illustrates an active metamaterial system with the structural integration of magnetic soft materials and magnetic SMPs. Its multiphysics responses under the cooperative thermal and magnetic stimuli enable shiftable mechanical behaviors such as shear, biaxial contraction and expansion, and bending, which considerably enhance the versatility of the metamaterial’s shape-changing capability [ 107 ]. An array of dipole elements can modify tilting angles under a relatively small magnetic field, and the configurable structure innovatively demonstrates tunable resonant frequency as an electromagnetic filter [ 128 ].…”

“…Copyright 2020, Wiley). (f) Active metamaterial with shiftable mechanical behaviors under the cooperative thermal and magnetic stimuli (Adapted with permission from [ 107 ]. Copyright 2020, American Chemical Society).…”

Programmable 4D Printing of Bioinspired Solvent‐Driven Morphing Composites

“…For example, plant seed organs (including pinecones, [ 27 ] pea pods, [ 28 ] wheat awns of wild wheat, [ 29,30 ] and pelargonium seed [ 31 ] ) anisotropically restrict expansion and contraction of matrix materials by the site‐specific aligned cellulose fibers during water absorption and desiccation, resulting in the complex deformation behaviors such as bending and torsion. Inspired by the morphing mechanism of plants, researchers in the process of 3D printing assisted by external fields such as shear field, [ 32–34 ] magnetic field, [ 23,35–40 ] and electric field [ 41,42 ] induce the orientation distribution of reinforced fibers inside the material, which endows the material system with anisotropy and realize complex shape deformation combined with the intelligent characteristics of matrix materials.…”