Liquid crystal ink for 3D printing
Cholesteric liquid crystals, an artificial material with properties between liquids and solid crystals, can mimic the colors of butterfly wings. Liquid crystals are used in televisions and smartphones, but future applications for health sensors or decorative lighting are difficult because the materials cannot be used in advanced and rapid production methods like 3D printing. The materials are not viscous enough to create strong, stable structures, and it is difficult to align the molecules to produce specific colors. TU / e researchers have solved these problems by developing a new light-reflecting liquid crystal ink that can be used with existing 3D printing techniques. The new research was published in the journal Advanced Materials.
For healthcare applications in flexible wearable sensors or decorative lighting, cholesteric liquid crystals are ideally suited. Until now, however, there has been a lack of an easy way to produce these materials and make devices from these materials.
“DIW is an extrusion-based 3D printing approach where ink is dispensed from a small nozzle onto a surface layer by layer. Current cholesteric liquid crystal inks cannot be printed with DIW, we have therefore created a liquid crystal ink compatible with DIW “, Sol said.
The new liquid crystal ink has several key properties. First, the ink’s light reflecting properties rely on the precise helical alignment of molecules throughout the material, which requires fine tuning of the printing process. Second, ink molecules can self-assemble into such structures that display colors similar to those of natural iridescent materials, like those of butterfly wings. Third, the new ink has a higher viscosity than the previous inks, which makes it suitable for DIW printing.
Finally, the new ink is new, easy to manufacture, easy to process, and based on materials previously developed by the SFD research group at TU / e for light-reflecting coatings, which helps make it suitable for use in light-reflecting coatings. 3D printing.
“To successfully print the new ink with DIW, we varied parameters such as print speed and temperature. And in order for the ink to print correctly, we also made an ink that contains low molecular weight liquid crystal. note Sol. Quite impressively, the researchers were able to use the new ink to print synthetic butterfly wings!
Since the new liquid crystal ink can be printed with DIW, it could be used in future printing procedures for personalized medical devices such as slim wearable biosensors that visually and colorfully interact with the wearer.
“Additionally, the combination of our new ink and DIW can be used to imprint the specialized optical structures needed for augmented reality headsets where real and artificial images are seamlessly combined. “ Sol said enthusiastically. “New materials could find their place in the HoloLenses of the future – now that would be something extraordinary! “