Researchers make progress in the field of 4D printing of ceramics

4D printing is an innovative manufacturing technology that has evolved from 3D printing and integrates smart materials and mechanical design into the printing process. Under the influence of external stimuli such as light, heat, electrical and magnetic fields, 4D-printed structures can change their shape or functionality over time, which offers enormous application potential in areas such as aerospace or biomedicine.

Professor Qi Ge from Southern University of Science and Technology (SUSTech) and Associate Professor Chao Yuan from Xi’an Jiaotong University have recently made significant progress in the field of 4D printing of ceramics. Their approach enables the direct fabrication of 4D-printed ceramics and opens up new possibilities for the design and application of ceramic structures in various engineering disciplines.

In their work, published in “Nature Communications”, the researchers presented a method based on the dehydration of hydrogel. They developed a photocurable ceramic elastomer suspension and acrylic acid hydrogel precursors for DLP printing. The printed ceramic elastomer body is highly stretchable and can withstand tensile elongation of up to 700%. The hydrogel serves as a driving material and shows a significant volumetric shrinkage of 65% due to dehydration as well as a 40-fold increase in modulus.

The researchers used multi-material DLP 3D printing technology to create patterned hydrogel ceramic laminates. These flat laminates develop into complex 3D structures through the dehydration of the hydrogel. After debinding and sintering at high temperatures, these structures are transformed into pure ceramics. The bending of the parts is reduced after sintering, which is due to the uneven shrinkage in the thickness of the laminate during sintering. The researchers developed a theoretical model to calculate the final curvature and created a design map showing the relationship between structural deformation and structural parameters.

By using hydrogel ceramic laminates at different positions in the flat pattern via multi-material DLP 3D printing, a variety of complex shapes can be realized. Compared to shape-assisted forming and manual folding, hydrogel dehydration-driven direct 4D printing enables easier and more efficient fabrication of complex 3D ceramic objects.

This research was funded by the National Natural Science Foundation of China (NSFC), the Key Talent Recruitment Program of Guangdong Province and the Science, Technology and Innovation Commission of Shenzhen Municipality.