This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Polymers used for light-based 3D printing are very stable because of their chemical structure, but they are typically hard to recycle. A research team led by Professor Dr.
Eva Blasco, a researcher at the Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM) at Heidelberg University, has designed a polymer material that can be disassembled into its individual components when needed. The work is published in the journal Advanced Materials. A chemical "key" causes already printed material to break down into its molecular building blocks within seconds.
The components can be recovered and reused in a circular manufacturing process. Among additive manufacturing—i.e., 3D printing—methods, high-precision light-based approaches such as digital light processing stand out for producing small and complex structures. They are used, for example, in personalized medicine or soft robotics.
These technologies are based on liquid "inks" that cure into solid, three-dimensional structures when exposed to light. They are usually made of so-called thermosets, whose building blocks are permanently and irreversibly linked in a permanent network. This makes the materials very stable, but they are practically nonrecyclable and, according to the scientists, could become a source of constant waste streams.
To make light-based 3D printing more sustainable, the Heidelberg research team has designed a so-called metastable material that can be broken down into its individual components without compromising precision, quality or mechanical stability. As the basis for their work, the scientists used a special polymer that reacts to a chemical signal. "The long molecular chain is held together by a single predetermined breaking point.
As soon as a specific chemical trigger opens this site, the entire chain breaks down into its constituent parts within seconds at room temperature, like a row of dominoes," explains Johannes Markhart, a doctoral student conducting research in Blasco's team. The predetermined breaking point functions like a lock that opens only with the right key. In its experiments, the research team was able to use the novel metastable material to produce various complex three-dimensional structures with details on the micrometer scale, thereby demonstrating its suitability as a high-resolution "ink." "It combines high print quality with a property that has been virtually nonexistent in polymer materials for 3D printing until now: It can be completely disassembled into its individual parts without leaving any residue," says Markhart.
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