A team of researchers at Virginia Tech’s Macromolecules Innovation Institute (MII) have developed a new process to 3D print Kapton, one of the most-desired materials in the electronics and aerospace industries.
Kapton is a polyimide with exceptional thermal and electrical properties. It has a degradation temperature around 550 degrees Celsius, doesn’t dissolve in solvents, acts as an electrical insulator, and is resistant to ultraviolet irradiation. It’s also very stable because the molecule is all-aromatic, containing rings that restrict rotation. Up to now, Kapton has only been available in sheets of thin film, which amongst other uses, is the basis for the “gold foil” that wraps around satellites to insulate them.
But last year researchers at MII turned to stereolithography to 3D print Kapton. However, researchers, from the Long Group in the Department of Chemistry and the Design, Research, and Education for Additive Manufacturing Systems (DREAMS) Lab in the Department of Mechanical Engineering, have now found a second way to 3D print Kapton.
This process, called direct ink write (DIW), was detailed in a recent article in ACS Applied Materials & Interfaces. The researchers now have greater flexibility in incorporating Kapton into manufacturing processes. Daniel Rau, one of the co-authors and a Ph.D. student in the DREAMS Lab, explained: “Because it’s so simple, (DIW) gives us incredible flexibility on the ink, synthesis, and the properties it has.” The DIW-printed Kapton has similar properties to the commercially available Kapton film up to 400 °C, and its degradation temperature is 534 °C, only slightly lower than the commercial Kapton that degrades at 550 °C.
The stereolithography process is better suited for 3D printing entire objects, but Rau says that direct ink write is better for printing multiple materials side-by-side. Christopher Williams, director of the DREAMS Lab and associate director of MII, said that beyond multi-material printing, they can also now print Kapton directly onto an existing material, which stereolithography cannot do. This includes the possibility of simultaneous printing of conductive materials with Kapton as an insulator. Williams added that they can also now print Kapton on curved surfaces using direct ink write.