Additive Manufacturing of Transparent Multi-component Nanoporous Glasses

Fabrication of glass with complex geometric structures by digital additive manufacturing (3D printing) presents a paradigm shift in glass design and molding processes. Till now, 3D printing glasses have suffered from limited printed glass materials and the low resolution of particle-based or fused glass technologies. Herein, a high-resolution 3D printing of transparent nanoporous glass is presented, by the combination of transparent photo-curable sol-gel printing compositions and digital light processing (DLP) technology. Multi-component glass, including binary (Al2O3-SiO2), ternary (ZnO-Al2O3-SiO2, TiO2-Al2O3-SiO2), and quaternary oxide (CaO-P2O5-Al2O3-SiO2) nanoporous glass objects with complex shapes, high spatial resolutions, and multi-oxide chemical compositions are fabricated, by DLP printing and subsequent sintering process. The uniform nanopores of Al2O3-SiO2-based nanoporous glasses with the diameter (~6.04 nm) which is much smaller than the visible light wavelength, result in high transmittance (> 95%) at the visible range. The high surface area of printed glass objectives allows post-functionalization via the adsorption of functional guest molecules. We successfully demonstrated the photoluminescence and hydrophobic modification of 3D printed glass objectives. This work extends the scope of 3D printing to transparent nanoporous glasses with complex geometry and facile functionalization, making them available for a wide range of applications.