From 3D Printing to 4D Printing: the morphing of objects
Engineers from Rutgers University developed a “4D printing” method from 3D printing that could lead to the development of “living” structures in human organs and tissues, soft robots and targeted drug delivery.
According to Howon Lee, Assistant professor in the Department of Mechanical and Aerospace Engineering at Rutgers University-New Brunswick, the 4D printing technique involves printing a 3D object with a hydrogel (water-containing gel) that changes shape over time when temperatures change.
The research demonstrates that 3D printing of hydrogels remains solid and retain their shape despite containing water. For the record, hydrogels can be found in contact lenses, diapers and the human body.
The potential of the gel
Thanks to this gel, organs such as the lungs are more rigid and can integrate small molecules like water or drugs that can be transported in the body and released. “It could also create a new area of soft robotics, and enable new applications in flexible sensors and actuators, biomedical devices and platforms or scaffolds for cells to grow”, Lee said.
It should be noticed that the full potential of the gel has not been discovered yet. However, adding another dimension is a premiere in the research.
In this research, a lithography-based technique has been used because it enables to 3D print various materials using a special resin which is the hydrogel. In other terms, a chemical acts as a binder, another chemical facilitates bonding when light hits it and a dye controls light penetration.
Results show that below 32 degrees Celsius (about 90 degrees Fahrenheit), the hydrogel absorbs more water and swells in size. When temperatures exceed 32 degrees Celsius, the hydrogel begins to expel water and shrinks.
“If you have full control of the shape, then you can program its function,” Lee said. “I think that’s the power of 3D printing of shape-shifting material. You can apply this principle almost everywhere.”
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