Described in a Nature Communications article titled "Fabrication of arbitrary three-dimensional suspended hollow microstructures in transparent fused silica glass", the new microfabrication method can yield 3D hollow glass structures with complex helicoidal patterns.
The research was a collaboration between the University of Freiburg, the ETH Zürich, the University of Würzburg, and Nanoscribe GmbH, a provider or 3D microfabrication tools. A practical example was the additive fabrication of an out-of-plane 3D mixer as the sacrificial template within the process chain for the fabrication of fused silica hollow structures.
Once the polymer microstructure is printed, a liquid nanocomposite glass material is simply cast on top of the polymer template and solidified using UV light. Along the sacrificial template replication process, a thermal treatment ultimately turns the nanocomposite material (essentially silica nanoparticles in a binder) into fused silica glass, molded to the shape of the 3D sacrificial microstructure. The debinding process (at 600ºC) and the sintering (at 1300ºC) removes the sacrificial polymer structure entirely, leaving hollow micro-channels within the glass.
The smallest fabricated channel realized in the research project features a diameter of approximately 7 micrometers. The precise out-of-plane channel guidance of the mixer clearly underlines the feasibility of complex glass designs.
Nanoscribe aims to further develop the manufacturing process and eventually bring it to the industrial market. In addition to various polymers, ceramics and metals, glass could soon become another attractive material for Nanoscribe's microfabrication technology, in particular for highly-precise 3D microfluidic systems.
Nanoscribe - www.nanoscribe.com