Hong Kong Scientists Develop World’s First 4D Printing for Ceramics

Researchers from the City University of Hong Kong (CityU) have developed the world’s first-ever 4D printing process for ceramics.

This ground-breaking advancement in materials research could pave way for new structural applications of ceramics.

Ceramic has a high melting point, so it is difficult to use conventional laser printing to make ceramics.

Existing 3D printed ceramic precursors also hinder the production of ceramics with complex shapes.

The CityU team has now found a way to remedy this by developing a novel ceramic ink, which is a mixture of polymers and ceramic nanoparticles.

According to the researchers, the 3D printed ceramic precursors printed with this novel ink are soft and can be stretched three times beyond their initial length.

These flexible and stretchable ceramic precursors allow complex shapes, such as origami folding. With proper heat treatment, ceramics with complex shapes can be made, the researchers intone.

The research team has achieved one more breakthrough by developing two methods of 4D printing of ceramics.

4D printing is conventional 3D printing combined with the additional element of time as the fourth dimension, where the printed objects can re-shape or self-assemble themselves over time with external stimuli, such as mechanical force, temperature, or a magnetic field.

In this research, the team made use of the elastic energy stored in the stretched precursors for shape morphing.

When the stretched ceramic precursors are released, they undergo self-reshaping. After heat treatment, the precursors turn into ceramics.

The resultant elastomer-derived ceramics are mechanically robust. They can have a high compressive strength-to-density ratio (547 MPa on 1.6 g cm-3 microlattice), and they can come in large sizes with high strength compared to other printed ceramics.

In the second method, the designed pattern was directly printed on the stretched ceramic precursor. It was then released under computer-programming control and underwent the self-morphing process.