Embedded 3D Printing of Architected Ceramics via Microwave‐Activated Polymerization

Abstract

polymers, [31,32] and foams [33][34][35] in a layerwise manner. To date, DIW has been used to produce periodic ceramic architectures ranging from honeycombs to 3D woodpile lattices. However, despite significant advances in both light-and ink-based 3DP methods, freeform fabrication of ceramic architectures with arbitrary composition and geometry remains challenging.Embedded 3D (EMB3D) printing offers a promising route for creating architected ceramics via freeform writing in a support matrix. In its initial embodiment, vascularized systems were produced by writing sacrificial inks within soft [36,37] and living [38] matrices. This method was extended to create soft strain sensors and proprioceptive robotic grippers by writing conductive particle-filled [39] and ionogel inks [40] within elastomeric matrices, respectively. More recently, other research groups have generated ceramic filaments by printing colloidal inks within a sacrificial support matrix. [41,42] However, they did not create complex structures nor report their microstructural or mechanical properties after densification. Hence, the ability to dry, cure, and harvest ceramic parts produced by EMB3D printing for load-bearing applications has yet to be demonstrated.Here, we report a method for fabricating architected ceramics with controlled composition in arbitrary geometries that combines EMB3D printing with microwave-activated curing. [43,44] We first created concentrated colloidal gels that contain thermally curable species and are compatible with our silicone-based support matrix while exhibiting the requisite rheological properties for EMB3D printing. As exemplars, we printed architected ceramics in the form of monolithic and multimaterial lattices, as well as interpenetrating chain structures. Next, we investigated the effects of microwave-activated curing on the ability to generate parts with sufficient handling strength for their removal from the support matrix and subsequent densification during sintering. Our integrated manufacturing approach enables complex ceramics architectures to be manufactured with programmable composition in freeform shapes that may be of potential interest for structural, biomedical, and energy applications. Results and DiscussionEMB3D printing with microwave-activated curing is shown in Figure 1a. Printed filaments are extruded through a nozzle Light-and ink-based 3D printing methods have vastly expanded the design space and geometric complexity of architected ceramics. However, light-based methods are typically confined to a relatively narrow range of preceramic and particle-laden resins, while ink-based methods are limited in geometric complexity due to layerwise assembly. Here, embedded 3D printing is combined with microwave-activated curing to generate architected ceramics with spatially controlled composition in freeform shapes. Aqueous colloidal inks are printed within a support matrix, rapidly cured via microwave-activated polymerization, and subsequently dried and sintered into dense architectures composed of ...

Architected Poly(ionic liquid) Composites with Spatially Programmable Mechanical Properties and Mixed Conductivity

“…48,50 To meet the required rheological behaviors as well as the material and processing needs described above, we use DOWSIL 9041, a solvent-free, granular microgel silicone paste, as a transparent, sacrificial matrix material. 50,51 The granular silicone matrix is diluted with silicone oil (500 cSt, 6 wt %) to lower the yield stress, τ y . The electrolyte ink comprises an IL monomer [1-ethyl-3-methyl imidazolium (3sulfopropyl) acrylate (ES)] (Figures 1a and S3) containing 4methoxyphenol (0.003 equiv) as an inhibitor, 1.5 wt % of a cross-linker [polyethylene glycol diacrylate (PEGDA) 250], and 1.5 wt % of a photoinitiator (Irgacure 754) for free-radical polymerization after printing.…”

“…10,11,46,47,52 We first introduce a modular IL monomer ink design for EMB3D printing pIL composites in a sacrificial granular matrix material. 50,51,53 We characterize the rheological properties of a representative IL monomer ink whose rheological behaviors are tuned with the hexagonal boron nitride (hBN) nanoparticles. We then use cyclic compression testing to examine the viscoelastic response of the pIL composite lattices with different geometries and leverage the modularity of our approach to print EMB3D lattices with different IL monomers and functional fillers.…”

“…We demonstrate our method by printing lattice structures that are lightweight, free-standing, and load-bearing. We use embedded 3D (EMB3D) printing to access a regime of ink rheological properties that typically pose challenges for conventional light-based printing methods. ,− Moreover, by enabling the fabrication of pIL composites from ionic liquid (IL) monomer inks that are rheologically modified with functional fillers, we enable the fabrication of structural electrolytes with mechanical and electrical properties that can be tailored for sensors, actuators, soft robotics, bioelectronics, and energy storage devices. ,,,, We first introduce a modular IL monomer ink design for EMB3D printing pIL composites in a sacrificial granular matrix material. ,, We characterize the rheological properties of a representative IL monomer ink whose rheological behaviors are tuned with the hexagonal boron nitride (hBN) nanoparticles. We then use cyclic compression testing to examine the viscoelastic response of the pIL composite lattices with different geometries and leverage the modularity of our approach to print EMB3D lattices with different IL monomers and functional fillers.…”

Conformable Multifunctional Space Fabric by Metal 3D Printing for Collision Hazard Protection and Self-Powered Monitoring

“…where E is the gravitational potential energy, m is the mass, g is the gravitational acceleration of Earth's surface, and h is the height of fall. Similarly, the impact characteristics of a steel ball of the same weight dropped from different heights (10,20,30,40, and 50 cm) were also tested. It can be seen from the figures that the voltage signal increases gradually with increasing height (Figure 4f), the gravitational potential energy and the impact force also increase as well (Figure 4g), and the inset shows the schematic diagram of a ball of the same weight dropped at different heights.…”

“…Thus, it is definitely the most promising solution to utilize the equipment and materials available on-site for the preparation of the required supplies and tools. 3D printing technology also known as additive manufacturing (AM) technology, which has a wide range of applications in the medical, , aerospace, , and construction fields , by using metal powders, , ceramics, , or polymers , (perfectly suitable for the wide materials selections of TENG) to prepare simple or complex parts by combining the advantages of standardized and customized production to produce parts with high strength, lightweight, and outstanding mechanical properties. − Through the innovative prowess of 3D printing, astronauts are bestowed with the power to manufacture essential components, equipment, and replacements in real time, precisely tailored to the unique demands of each mission. − The remarkable ability eliminates the need for reliance on earth supply, thus streamlining logistics and significantly elevating mission sustainability and reliability. Additionally, 3D printing technology obviates the necessity to premanufacture and package large quantities of equipment instead of manufacturing what is needed on demand in real time.…”