Chemists at Martin Luther University (MLU), Halle-Wittenberg, Germany have developed a way to integrate liquids directly into materials during a 3D printing process. Current 3D printing methods for integrating liquids are limited to materials liquefied through heat that become solid after printing. If a finished product is to contain liquid components, these are usually added afterwards. This is time-consuming and costly.
“The future lies in more complex methods that combine several production steps,” says Professor Wolfgang Binder from the Institute of Chemistry at MLU. “That is why we were looking for a way to integrate liquids directly into the material during the printing process.”
Binder and his colleague Harald Rupp combined common 3D printing processes with traditional printing methods such as those used in inkjet or laser printers. Liquids are added drop by drop at the desired location during the extrusion of the basic material. This allows them to be integrated directly and into the material in a targeted manner.
The chemists demonstrated their method works in two examples. First, they integrated an active liquid substance into a biodegradable material. They proved the active ingredient was not affected by the printing process and remained active. This new process could facilitate production of materials used as drug depots in the pharmaceutical industry which can be slowly broken down by the body. They can be used after operations, for example, to prevent inflammation.
Second, the scientists integrated a luminous liquid into a plastic material. When the material becomes damaged, the liquid leaks out and indicates where damage has occurred. One could imprint something like this into a small part of a product that is exposed to particularly high levels of stress, says Binder. For example, in parts of cars or aircraft that are under a lot of strain. According to Binder, so far, damage to plastic materials has been difficult to detect – unlike damage to metals, where X-rays can expose micro-cracks. The new approach could therefore increase safety.
The process could also be used in many other applications, and the team plans to print parts of batteries. But further development outside its laboratory would be needed to scale up to produce industrial quantities. The research, supported by the German Research Foundation and the EU as part of the Horizon 2020 program, was published in Advanced Materials Technologies.
Image – A lattice structure (left) inside the 3D-printed material (right) contains added liquids. Courtesy of Harald Rupp, Uni Halle.
For more information:
Macromolecular Chemistry / MLU
https://macrochem.uni-halle.de/
