4D printing of reconfigurable metamaterials and devices

Abstract

Shape-shifting materials are a powerful tool for the fabrication of reconfigurable materials. Upon activation, not only a change in their shape but also a large shift in their material properties can be realized. As compared with the 4D printing of 2D-to-3D shape-shifting materials, the 4D printing of reconfigurable (i.e., 3D-to-3D shape-shifting) materials remains challenging. That is caused by the intrinsically 2D nature of the layer-by-layer manner of fabrication, which limits the possible shape-shifting modes of 4D printed reconfigurable materials. Here, we present a single-step production method for the fabrication and programming of 3D-to-3D shape-changing materials, which requires nothing more than a simple modification of widely available fused deposition modeling (FDM) printers. This simple modification allows the printer to print on curved surfaces. We demonstrate how this modified printer can be combined with various design strategies to achieve high levels of complexity and versatility in the 3D-to-3D shape-shifting behavior of our reconfigurable materials and devices. We showcase the potential of the proposed approach for the fabrication of deployable medical devices including deployable bifurcation stents that are otherwise extremely challenging to create.

Preparation of Smart Materials by Additive Manufacturing Technologies: A Review

“…As the Figure 5 suggests, 4D printing can be envisioned as an advanced printing method where a 3D printed structure alters itself (as shown in Figure 5 with light activation) into a different object with the effect of external energy input, such as heat, light or other available environmental stimuli [49][50][51][52]. Four-dimensional printing is programmed to alter a 3D printed structure, in terms of its shape, property, and functionality [53][54][55][56][57][58]. It is endowed with properties, such as self-assembly, self-repairability, and multifunctionality.…”

Smart Additive Manufacturing: The Path to the Digital Value Chain

“…4D printing is one of the most recent achievements in AM technologies and has attracted considerable attention in academic and industrial circles since 2013, although commercialization still requires additional research and development [50]. Known as the fabrication of a complex spontaneous structure that changes over time, intentionally responding to external stimuli, 4D printing has its origins in 3D printing, but goes beyond 3D printing, as manufactured objects are no longer static and can be transformed into complex structures by changing size, shape, other properties, and functionality, making 3D printing alive [51,52]. These techniques have been applied in the field of flexible robots, grippers, and tissue engineering.…”

Micro‐Scale Auxetic Hierarchical Mechanical Metamaterials for Shape Morphing

“…In addition, the task of designing and manufacturing such materials becomes even more difficult at small scales such as the microscale that are crucial from the point of view of many new types of applications, for example, flexible electronics [24,25] and specialized medical equipment. [26,27] However, despite the level of difficulty, over the was only demonstrated for macroscopic prototypes. On the other hand, there are numerous types of applications (e.g., biomedical devices and flexible electronics) where similar materials with the ability to exhibit programmable auxetic behavior would be of great importance at a much lower scale with the emphasis on the micro-scale.…”

“…In addition, the task of designing and manufacturing such materials becomes even more difficult at small scales such as the microscale that are crucial from the point of view of many new types of applications, for example, flexible electronics [ 24,25 ] and specialized medical equipment. [ 26,27 ] However, despite the level of difficulty, over the years, it has been possible to note an emergence of promising directions of studies that address the possibility of observing these effects. In fact, one of the most interesting directions of studies related to this topic are mechanical metamaterials, [ 3,28–32 ] that is, structures that can exhibit counterintuitive mechanical behavior based primarily on their design.…”