For some materials, researchers have already moved beyond 3D printing to what’s being called 4D printing. In this process, time becomes the fourth dimension and objects can transform themselves over time when influenced by elements such as heat, mechanical force, or a magnetic field.
Now, scientists in China have developed a novel ink that takes ceramics into this 4D printing realm for the first time, paving the way for new structural applications of the material—including for electronic devices and aerospace. Specifically, a team at City University of Hong Kong created a ceramic ink using a mixture of polymers and ceramic nanoparticles that can print ceramic precursors that are soft and can be stretched three times beyond their initial length.
This malleability allows the material to be turned into complex shapes that weren’t previously possible with ceramics, such as origami folding, said Professor Lu Jian, chair professor of mechanical engineering at the university. “With the versatile shape-morphing capability of the printed ceramic precursors, its application can be huge,” he said in a news release by City University.
Typically, ceramics are complex to cast and shape because of the material’s extremely high melting temperature, and existing 3D-printed ceramic precursors are typically difficult to deform, which has limited the production of ceramics with complex shapes. Through the work of Lu and his team, ceramic precursors could self-reshape using elastic energy stored inside the material that, when released, caused the transformation. After treating the precursors with heat, they turned into ceramics, he said. Researchers published a paper on their work in the journal Science Advances.
|Professor Lu Jian and Dr. Liu Guo from the City University of Hong Kong led a research team that has developed 4D printing for ceramics, paving the way for new applications in electronics and aerospace. (Image source: CityU)|
The ceramics resulting from this process, derived from elastomers, have a robustness that isn’t typically found in other ceramics. Indeed, elastomers are generally flexible materials that have already shown promise for 4D printing, with good self-transformational capability. Moreover, the ceramics the team printed can come in large sizes and with more strength than other similar materials, Lu said, adding that the team had to overcome a number of challenges to develop the process.
“The whole process sounds simple, but it’s not,” he explained in the CityU release. “From making the ink to developing the printing system, we tried many times and different methods. Like squeezing icing on a cake, there are a lot of factors that can affect the outcome, ranging from the type of cream and the size of the nozzle to the speed and force of squeezing and the temperature.”
Lu and his team envision a number of applications for their research. One is for electronic devices, as ceramic materials have better electromagnetic-signal transmission capabilities than metallic ones. Researchers believe that ceramic products will play a key role in the future manufacturing of electronic products—especially with the advent of 5G networks.
The aerospace industry is another area in which 4D-printed ceramic materials can potentially be used, Lu said. “Since ceramic is a mechanically robust material that can tolerate high temperatures, the 4D-printed ceramic has high potential to be used as a propulsion component in the aerospace field,” he said.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco, and New York City. In her free time, she enjoys surfing, traveling, music, yoga, and cooking. She currently resides in a village on the southwest coast of Portugal.
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