USC: Researchers Inspired by Nature & Nacre for 3D Printing Strong, Conductive Parts

University of Southern California researchers delve into the inspiration of nature in ‘Electrically assisted 3D printing of nacre-inspired structures with self-sensing capability,’ inspired by the strength of shells in building ‘electrically assisted’ 3D parts, with the help of conductive materials. The structure of nacre is popular as a model today because it can unlock the secret to mechanical performance, and as the researchers point out, its composition is like a brick and mortar architecture. As is so often required for vital industrial 3D printed parts, the nacre structure allows for a lightweight yet strong structure.

“Recently, different types of nacre-inspired layered nanocomposites have been fabricated with inorganic additives, including glass flake, alumina flake, graphene, and graphene nanoplatelets,” state the researchers. “Traditional bottom-up assembly processes, including vacuum filtration, spray coating, ice templating, and self-assembly, have been intensively studied to fabricate nacre-inspired structures.”

So far, however, these types of methods have been devoted to the 2D realm, in creating more simple shapes—and for one main reason: it is difficult to use such techniques for creating 3D objects that are ‘enhanced’ and mechanically strong. The researchers see 3D printing as the possible ticket to success in overcoming previous obstacles for fabrication of complex structures that are not only inspired by nature but can be imbued with powerful electrical and mechanical qualities.

Schematic diagram of the electrically assisted 3D-printing platform for the construction of nacre-inspired structures.

In their research, the team outlines their new procedure for 3D printing in photocurable resin with aligned graphene nanoplatelets, also known as aGNs. The structures they have been able to 3D print are promising; in fact, they are as strong as regular graphene nanoplatelets, and as tough as real nacre.

“A smart helmet with both protective property and self-sensing capability can be fabricated using the electrically assisted 3D Eprinting process,” state the authors. “The bioinspired brick and mortar architecture enhance the mechanical strength and electrical conduction by aligning GN in each layer to maximize their performance by crack deflection under loading. The electrically assisted 3D-printing method can build a multifunctional lightweight and strong 3D structure with electrically self-sensing capability.”

In a somewhat amazing discovery, the research team realized that just as true nacre can deflect cracks, so can the 3D printed version. They found that as energy dissipation is enhanced by the features allowing for such deflection, greater toughness is achieved in the structures. The fabricated version also displays enhanced conductivity which could prove beneficial for a variety of applications, but the researchers again mention how useful it would be in creating armor. The customization options are vast also, including wearables and other smart technology too.

“This study shows that the alignment of GN creates the bridge and interlock, which is essential to confer the stress-induced damage in the 3D-printed structure. The developed electrically assisted 3D-printing process can fabricate structures with excellent integrated mechanical and electrical properties as well as complex 3D shapes,” concluded the researchers. “Such a new fabrication technique could enable the design and fabrication of the smart structures that are lightweight yet strong for various potential applications in biomedical, aerospace, transportation, sports, and military industries.”

Mechanical property and microstructure study of 3D-printed nacre.

Being able to print lightweight yet strong parts is a major benefit of 3D printing, often allowing users and large companies to innovate like never—simply because they never had such materials and technology at their fingertips before. Applications such as automotive, aerospace, medical, sports, and more are all being impacted.

While the more technical term shell nacre is not one that everyone may be familiar with, mother-of-pearl usually is. And you may be surprised at how often it has been connected with 3D printing, from the study of mechanical load in mollusks to inspiration from conchs to the development of synthetic bone. Find out more about nacre-inspired structures with sensors here. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.