This microscopic flower is growing thanks to a nitroxide-mediated polymerization reaction. It was created in the lab of Eva Blasco, a professor at the Centre for Advanced Materials at Heidelberg University. Blasco’s group works on “4D printing” with functional polymer–based materials—in other words, 3D-printable smart polymers that can be changed in a controlled way over time. By incorporating alkoxyamine functional groups into poly(ethylene glycol) diacrylate, the researchers created a dynamic covalent material that could be shaped into 3D structures using two-photon laser printing and then undergo post-printing modifications. The researchers could change the crosslinking density through nitroxide exchange to make the material softer. Or they could polymerize a new monomer (they used styrene) onto the material to change its size and mechanical properties while preserving the overall shape. 4D printing could be useful in medicine, microrobotics or other applications where it would be useful to print an object and then make adjustments to it. The group recently published their work in Advanced Functional Materials (DOI: 10.1002/adfm.202207826) with collaborators at Karlsruhe Institute of Technology.
Credit: Eva Blasco
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