Research from the University of Nottingham has demonstrated the viability of 3D printing for fabricating structures using advanced materials that switch states when exposed to different environmental stimuli such as light. The innovative research project could have far reaching implications for the future of 3D printed electronics, medical devices and quantum computing devices.
As detailed in a study published in the journal Advanced Materials, the researchers, led by Dr. Victor Sans Sangorrin from the Faculty of Engineering and Dr. Graham Newton from the School of Chemistry, have successfully 3D printed advanced polymer materials containing photochromic molecules. The presence of the molecules enables the printed material to effectively change colour when exposed to light—the same idea behind photochromic eyewear which darkens when exposed to the sun.
“This bottom-up approach to device fabrication will push the boundaries of additive manufacturing like never before,” said Dr. Sans. “Using a unique integrated design approach, we have demonstrated functional synergy between photochromic molecules and polymers in a fully 3D printed device. Our approach expands the toolbox of advanced materials available to engineers developing devices for real-world problems.”
As part of the study, the research team developed photoactive molecules (polyoxometalates or POMs) which transition from colourless to blue when exposed to light (and back to colourless when exposed to oxygen from the air). These special molecules were then added to a customized polymer, specifically a polymerisable ionic liquid (or PIL), creating an advanced composite material, processable using DLP 3D printing technologies.
The photochromic reaction triggered in the printed material, explains Dr. Sans, is the result of “rich multi-electron redox properties of the molecular hybrid organic-inorganic materials (POMs)” and offers a range of advanced properties. “Applications for larger information storage based on multiple redox states can be easily envisioned,” he adds.
“We can now take any molecules that change properties upon exposure to light and print them into composites with almost any shape or size,” added Dr Newton. “In theory, it would be possible to reversibly encode something quite complex like a QR code or a barcode, and then wipe the material clean, almost like cleaning a whiteboard with an eraser. While our devices currently operate using colour changes, this approach could be used to develop materials for energy storage and electronics.”
The game-changing research, which is supported by the Leverhulme Trust, the German Academic Exchange service and the University of Nottingham, could have applications in the development of 3D printed devices in the electronics, medical and quantum computing industries, to name just a few. The innovative 3D printable materials could also be used in applications for energy materials, CO2 valorization and antimicrobials.
“We are actively exploring all these areas,” said Dr. Sans. “Both POM and PILs are important materials with applications in these fields, and the specific design for 3D printing represents an extremely exciting field for research and development.”