Scientists at the KTH Royal Institute of Technology in Sweden have developed a new 3D-printing technique for silica glass that could revolutionize the manufacturing process. In a recent paper published in the journal Nature Communications, the team showcased their method by 3D-printing the world’s smallest wine glass with a rim smaller than the width of a human hair, as well as an optical resonator for fiber optic telecommunications systems.
Silica glass, which is commonly used in the production of optical fibers, has proven to be challenging to 3D print, especially at the microscale. Previous methods relied on sol-gel processes that involved organic mixtures loaded with silica nanoparticles. However, these methods resulted in composite structures that lacked the desired properties of pure silica glass. Additionally, an extra sintering step at high temperatures was required to remove organic residues, limiting the potential applications of the printed structures.
To overcome these limitations, the Swedish scientists turned to hydrogen silsesquioxane (HSQ), an inorganic material similar to silica. Their technique involves drop-casting HSQ dissolved in organic solvents onto a substrate, followed by tracing the desired 3D shape using a focused sub-picosecond laser beam. Any unexposed HSQ is then dissolved using a potassium hydroxide solution. Raman spectroscopy confirmed that the printed microstructures exhibited the features of silica glass.
While the printed structures still contained traces of residual hydrogen and carbon, the scientists found that annealing the structures at a lower temperature than the usual sintering step could remove these impurities. The resulting structures matched the spectrum of commercial fused silica glass substrate. Additionally, the shrinkage of the 3D-printed silica glass structures was significantly lower compared to structures produced using other 3D-printing methods.
In addition to the wine glass and optical resonator, the researchers also printed a tiny version of the KTH logo, a cantilever, a conical spiral, and a silica glass optical fiber tip. They believe that their method has the potential to be used in various applications, including customized lenses for medical devices and micro-robots. By coating the printed structures with nanodiamonds or ferrous nanoparticles, the properties can be further tailored for specific applications.
The team acknowledges that further optimization is needed for different applications, but they consider their method to be a significant breakthrough in 3D glass printing. The ability to 3D-print silica glass opens up new possibilities for the production of components used in fiber optic telecommunications systems and other industries.
This research demonstrates the potential of 3D-printing techniques in expanding the capabilities of glass manufacturing. With continued advancements in this field, we can expect to see new and innovative applications for 3D-printed glass in various industries in the near future.