3D printing of magneto-active smart materials for advanced actuators and soft robotics applications

TLDR

Additive manufacturing has transformed many engineering fields, and four‑dimensional printing of smart materials now enables soft structures that respond to stimuli such as pH, temperature, and magnetic fields, producing diverse shape‑morphing behaviors; incorporating magnetic particles yields magneto‑active soft materials that can be actuated by magneto‑thermal coupling for enhanced deformation. The review provides guidelines for 3D printing magneto‑active smart materials—polymers, composites, and hydrogels—to develop soft robots, wearable electronics, and biomimetic devices. It outlines fabrication strategies that integrate magnetic particles into soft matrices, detailing how magneto‑thermal coupling is achieved to produce controllable magneto‑deformations. The authors highlight current challenges and emerging research directions, forecasting that advances in magneto‑active structures will have a substantial impact on real‑world applications.

Abstract

In the contemporary era, novel manufacturing technologies like additive manufacturing (AM) have revolutionized the different engineering sectors including biomedical, aerospace, electronics, etc. Four-dimensional (4D) printing aka AM of smart materials is gaining popularity among the scientific community, which has the excellent ability to make soft structures such as soft robots, actuators, and grippers. These soft structures are developed by applying various stimuli such as pH, temperature, magnetic field, and many combinations onto soft materials. Stimuli in 3D printing permit various shape-morphing behaviors such as bending, twisting, folding, swelling, rolling, shrinking, origami, or locomotion. A wide variety of soft magnetic structures can be fabricated through the incorporation of soft or hard magnetic particles into soft materials resulting in magneto-active soft materials (MASMs). With this integration, magneto-thermal coupling actuation allows diverse magneto-deformations, facilitating the development of personalized devices that are capable of enhanced deformation. In this review, guidelines are provided on the 3D printing for MASMs such as magneto-active polymers (MAPs), magneto-active composites, and magneto-active hydrogels (MAHs) on the booming development of various smart and flexible devices such as soft robots, wearable electronics, and biomimetic devices. Moreover, 3D-printed soft robotics have an outstanding capacity to adapt to complicated situations for many advanced actuating applications. Finally, some current challenges and emerging areas in this exciting technology have been proposed. Lastly, it is anticipated that technological advancements in developing smart and intelligent magneto-active structures will have a significant impact on the design of real-world applications.