Singaporean scientists are working on revolutionizing 4D printing by fabricating a 3D material that can change its shape and back again any number of times.
According to the scientists from Singapore University of Technology and Design (SUTD) and Nanyang Technological University (NTU), the reversible 4D printing technology relies on the changing levels of heat during the different times of the day to change its shape.
4D printing essentially refers to the ability of 3D printed objects to change its shape over time caused by either heat or water while the reversibility aspect of it allows it to revert to its original shape.
This usually involves the use of hydrogel as a stimulus to achieve reversible 4D printing.
However, hydrogels lacks mechanical strength, and they become a limitation when used for load-bearing applications.
Moreover, other research work utilizing various layers of material as an alternative to hydrogel have only made the procedure to enable reversible actuation more tedious.
Now SUTD and NTU scientists have come up with a novel solution to address these issues.
They have utilized only two materials – VeroWhitePlus and TangoBlackPlus – which were more readily available and compatible for printing in a 3D polyjet printer compared to using a hydrogel.
Both materials have proven to retain considerable mechanical strength during and after actuation.
The process consists of the swelling of elastomer with ethanol to replace the function of hydrogel swelling to induce stress on the transition material.
When heated, the transition material changes its shape to a second shape.
After the ethanol is being dried out of the elastomer, heating the transition material again will then allow it to revert to its original shape.
According to the scientists, the elastomer plays a dual function in this whole process.
It is used both to induce stress in the programming stage and to store elastic energy in the material during the recovery stage.
This process of reversible 4D printing has also proven to be more precise when the material reverts to its original shape compared to manually stretching or inducing stress on it.
Image and content: Singapore University of Technology and Design (SUTD)
