Light‐Based Printing of Leachable Salt Molds for Facile Shaping of Complex Structures

Abstract

3D printing is a powerful manufacturing technology for shaping materials into complex structures. While the palette of printable materials continues to expand, the rheological and chemical requisites for printing are not always easy to fulfill. Here, a universal manufacturing platform is reported for shaping materials into intricate geometries without the need for their printability, but instead using light‐based printed salt structures as leachable molds. The salt structures are printed using photocurable resins loaded with NaCl particles. The printing, debinding, and sintering steps involved in the process are systematically investigated to identify ink formulations enabling the preparation of crack‐free salt templates. The experiments reveal that the formation of a load‐bearing network of salt particles is essential to prevent cracking of the mold during the process. By infiltrating the sintered salt molds and leaching the template in water, complex‐shaped architectures are created from diverse compositions such as biomedical silicone, chocolate, light metals, degradable elastomers, and fiber composites, thus demonstrating the universal, cost‐effective, and sustainable nature of this new manufacturing platform.

Light‐Based 3D Printing of Complex‐Shaped Photonic Colloidal Glasses

“…Earlier works suggest that this criterion is fulfilled if the apparent viscosity at shear rates between 30 and 100 s −1 is in the order of 10 3 and 10 4 mPa s for gravity-driven and wiping replenishing mechanisms, respectively. [42][43][44] Our rheological experiments reveal that resins loaded with 300 nm particles display viscosity values below this level for silica volume fractions up to 50 vol% (Figure 2a). Except for the resin with 20 vol% silica, all particle-laden formulations show a strong shear-thinning response.…”

Fabrication of a Novel Fluorescein Embedded Photocomposite Based on Interpenetrating Polymer Network (IPN) and Its Application in 4D Printing

“…Therefore, it can be assumed that since fluorescein also absorbs 405 nm wavelength light and can interact with the initiation system (Figure S9, Supporting Information), the addition of a small amount of fluorescein can promote the photopolymerization reaction, however, when more fluorescein is added the internal filter effect occurs, which prevents the light from penetrating and affects the photopolymerization reaction. [30] And homogeneous dispersion of fluorescein dyes in the photocomposite after photocuring was observed in Figure S4 (Supporting Information). 4D printing induced by water absorption and dehydration has been previously explored by several scientists.…”

Sacrificial biomaterials in 3D fabrication of scaffolds for tissue engineering applications

“…Leaching was also well combined with molding. [147][148][149][150][151] For instance, sacrificial PEO not only facilitates the processing of PCL by decreasing its viscosity but also improved the porosity and interconnectivity of the scaffold. Elongated and spindleshaped pore structures were fabricated with this cost-effective method 147 (Table 2).…”

“…The sacrificial core material was removed to form the hollow structure, and the salt was removed to form the micropores on the tube wall. Leaching was also well combined with molding 147–151 . For instance, sacrificial PEO not only facilitates the processing of PCL by decreasing its viscosity but also improved the porosity and interconnectivity of the scaffold.…”