Unlocking Transparency in 3D Printing of Polysiloxanes

Silica-polysiloxane inks have been developed for 3D printing, but their opaqueness has limited their potential in some applications. We addressed this limitation by precisely adjusting the base polysiloxane composition to achieve transparency. When solidified, these inks transmit about 90% of 700 nm light through 1 cm, showcasing useful transparency. We explored the dependence of the ink's rheological properties on silica particle distribution, showing that these properties are influenced by silica functionality, weight content, and processing. This understanding enables precise control over printing and object quality. Furthermore, our research also unveiled a thermochromic effect, where ink opacity changes with refractive index mismatch and temperature. This effect was explored in further detail and will be highlighted in this talk. To demonstrate practicality, we successfully printed encapsulants for LEDs, scintillators, and microfluidic mixing devices. These transparent inks find applications in advanced lighting and cutting-edge medical devices.<br/> <br/>This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS- 850030