3D printed shape-programmable magneto-active soft matter for biomimetic applications

Additive manufacturing (AM) or 3D printing is a digital manufacturing process and offers virtually limitless opportunities to develop structures/objects by tailoring material composition, processing conditions, and geometry technically at every point in an object. In this review, we present three different early adopted, however, widely used, polymer-based 3D printing processes; fused deposition modelling (FDM), selective laser sintering (SLS), and stereolithography (SLA) to create polymeric parts. The main aim of this review is to offer a comparative overview by correlating polymer material-process-properties for three different 3D printing techniques. Moreover, the advanced material-process requirements towards 4D printing via these print methods taking an example of magneto-active polymers is covered. Overall, this review highlights different aspects of these printing methods and serves as a guide to select a suitable print material and 3D print technique for the targeted polymeric material-based applications and also discusses the implementation practices towards 4D printing of polymer-based systems with a current state-of-the-art approach.

3D/4D Printing of Polymers: Fused Deposition Modelling (FDM), Selective Laser Sintering (SLS), and Stereolithography (SLA).

Gait and waist motions always contain massive personnel information and it is feasible to extract these data via wearable electronics for identification and healthcare based on the Internet of Things (IoT). There also remains a demand to develop a cost-effective human-machine interface to enhance the immersion during the long-term rehabilitation. Meanwhile, triboelectric nanogenerator (TENG) revealing its merits in both wearable electronics and IoT tends to be a possible solution. Herein, the authors present wearable TENG-based devices for gait analysis and waist motion capture to enhance the intelligence and performance of the lower-limb and waist rehabilitation. Four triboelectric sensors are equidistantly sewed onto a fabric belt to recognize the waist motion, enabling the real-time robotic manipulation and virtual game for immersion-enhanced waist training. The insole equipped with two TENG sensors is designed for walking status detection and a 98.4% identification accuracy for five different humans aiming at rehabilitation plan selection is achieved by leveraging machine learning technology to further analyze the signals. Through a lower-limb rehabilitation robot, the authors demonstrate that the sensory system performs well in user recognition, motion monitoring, as well as robot and gaming-aided training, showing its potential in IoT-based smart healthcare applications.

Wearable Triboelectric Sensors Enabled Gait Analysis and Waist Motion Capture for IoT-Based Smart Healthcare Applications

Design, manufacturing and applications of wearable triboelectric nanogenerators

Triboelectric and Piezoelectric Nanogenerators for Future Soft Robots and Machines.

Biomimetic actuators with stimuli-responsiveness, adaptivity, and designability have attracted extensive attention. Recently, soft intelligent actuators based on stimuli-responsive materials have been gradually developed, but it is still challenging to achieve various shape manipulations of actuators through a simple 3D printing technology. In this paper, a 3D printing strategy based on magneto-active materials is developed to manufacture various biomimetic magnetic actuators, in which the new printable magnetic filament is composed of a thermoplastic rubber material and magnetic particles. The continuous shape transformation of magnetic actuators is further demonstrated to imitate the motion characteristic of creatures, including the predation behavior of octopus tentacles, the flying behavior of the butterfly, and the flower blooming behavior of the plant. Furthermore, the magnetic field-induced deformation of the biomimetic structure can be simulated by the finite element method, which can further guide the structural design of the actuators. This work proves that the biomimetic actuator based on soft magneto-active materials has the advantages of programmable integrated structure, rapid prototyping, remote noncontact actuation, and rapid magnetic response. As a result, this 3D printing method possesses broad application prospects in soft robotics and other fields.

3D Printing Magnetic Actuators for Biomimetic Applications.

Advanced triboelectric nanogenerator with multi-mode energy harvesting and anti-impact properties for smart glove and wearable e-textile

Flexible, self-powered, magnetism/pressure dual-mode sensor based on magnetorheological plastomer

Temperature dependent magneto-mechanical properties of magnetorheological elastomers

A novel resonance sound absorber, whose resonant frequency characteristic can be varied by turning the external magnetic field, is constructed based on micro-perforated magnetorheological elastomer (MP-MRE). The influence of parameters, such as porosity, thickness, curing agent weight ratio and magnetic field intensity, are investigated to analyze the magneto-acoustic coupling property of MP-MRE sound absorber. By increasing the magnetic flux density, the resonant frequency of resonance sound absorber moves toward high frequency region. It is found the magnetic field-induced deformation of the MP-MRE and its pores affected the resonant frequency. When the magnetic flux density was increased from 0 to 132 mT, the maximum variation of the resonant frequency reached 304 Hz. Finally, originated from this unique magnetic controllability, the MP-MRE sound absorber shows broad potential in the tunable sound absorber at middle and low frequency range.

https://iopscience.iop.org/article/10.1088/1361-665X/ab57ec/pdf

Li Jun

Papers

3D Printing Magnetic Actuators for Biomimetic Applications.

Advanced triboelectric nanogenerator with multi-mode energy harvesting and anti-impact properties for smart glove and wearable e-textile

Flexible, self-powered, magnetism/pressure dual-mode sensor based on magnetorheological plastomer

Temperature dependent magneto-mechanical properties of magnetorheological elastomers

Magnetic-tunable sound absorber based on micro-perforated magnetorheological elastomer