Researchers from the University of Heidelberg have developed a new shape memory material that can be 3D printed with a high resolution both at the macro and the microscale
Newly developed smart polymers having life-like properties could open up new opportunities in fields such as micro-robotics or biomedicine. The team led by Prof. Blasco recently demonstrated one of the first examples of 3D-printed shape memory polymers at the microscale. In cooperation with the working group of biophysicist Prof. Dr. Joachim Spa3tz, a scientist at Ruperto Carola and Director at the Max Planck Institute for Medical Research have developed 3D printed microscopic geckos and octopuses using smart polymers whose size and mechanical properties can be altered on demand and with high precision. These “life-like” 3D microstructures were developed in the framework of the “3D Matter Made to Order” (3DMM2O) Cluster of Excellence, a collaboration between Ruperto Carola and the Karlsruhe Institute of Technology (KIT)
“Manufacturing programmable materials whose mechanical properties can be adapted on demand is highly desired for many applications,” states Junior Professor Dr. Eva Blasco, group leader at the Institute of Organic Chemistry and the Institute for Molecular Systems Engineering and Advanced Materials of Heidelberg University. In 4D printing, the additional fourth dimension refers to the ability of 3D-printed objects to alter their properties as desired. This property is similar to shape memory polymers i.e. smart materials that return to their original shape in response to an external stimulus such as temperature.
This unique shape memory material developed can be 3D printed with a high resolution both at the macro and at the microscale. The structures invented consist of box-shaped microarchitectures whose lids close in response to heat and can then be reopened. “These tiny structures show unusual shape memory properties at low activation temperatures, which is extremely interesting for bio applications,” explains Christoph Spiegel, a doctoral researcher in the working group of Eva Blasco.
Researchers used adaptive materials and successfully developed much more complex 3D microstructures like geckos, octopuses, and even sunflowers with “life-like” properties in a follow-up study. These materials are dependent on dynamic chemical bonds. The Heidelberg researchers examined that alkoxyamines are particularly suitable for this purpose. After the printing process, these dynamic bonds allow for the complex, micrometric structures to grow eight-fold in just a few hours and to harden while maintaining their shape. “Conventional inks do not offer such features,” emphasizes Prof. Blasco. “Adaptive materials containing dynamic bonds have a bright future in the field of 3D printing,” adds the chemist.
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