Noncomposite Could Replace Polymers in Industrial Applications

A new technology could make it possible to produce and use high-quality glass materials in place of polymers. The innovation, known as Glassomer, could be used in optical, photonic, medical, and industrial applications.

Glassomer is a solid nanocomposite that can be structured using polymer molding and subtractive technologies at submicrometer resolution. After polymer processing, Glassomer is turned into optical-grade fused silica glass during a final heat treatment. According to its inventors, the resulting glass has the same optical transparency as commercial fused silica and a smooth surface with a roughness of a few nanometers.

Glassomer can be milled, turned, lasered, or processed in computer numeric control (CNC) machines — just like a conventional polymer. Courtesy of Markus Breig/KIT.

Scientists at Karlsruher Institute of Technology (KIT) mixed glass particles, 40 nm each, with a liquid polymer. The mix can be hardened to a solid through heating or exposure to light. In the Glassomer, the solid nanoparticles will make up roughly 60 percent of the total volume. The rest is organic binder. The polymer acts like a bonding agent, maintaining the matrix of glass particles and thus the shape of the material.

For fabricating high-performance lenses, the researchers produce a Glassomer rod, from which the lenses are cut. For highly pure quartz glass, the researchers remove the polymers in the composite by heating the lenses in a furnace at 500 to 600 °C, causing the polymer to be burned to CO₂. Then, to close any gaps in the material that result from this process, the lenses are sintered at 1300 °C. During the sintering process, the remaining glass particles are densified to pore-free glass.

Glassomer can be milled, turned, laser-machined, or processed in computer numeric control (CNC) machines just like a conventional polymer.

“The entire range of polymer-forming technologies is now opened for glass,” said Bastian E. Rapp, head of NeptunLab at KIT’s Institute of Microstructure Technology.

With Glassomer, glass components similar to that shown here can be produced by cutting. Courtesy of Markus Breig/KIT.

This advance in materials processing could make high-performance fused silica glass components accessible to high-throughput fabrication technologies.

“Our process is suited for mass production. Production and use of quartz glass are much cheaper, more sustainable, and more energy-efficient than those of a special polymer,” said Rapp.

There are plans to commercialize Glassomer.

In 2017, Rapp and his lab applied the Glassomer mixture for 3D printing and demonstrated its suitability for additive manufacturing. For more information about this innovation, see Rapp’s webinar presentation from November 2017, Next Generation 3D Printing: The Emergence of Enabling Materials.

The research was published in Advanced Materials (doi:10.1002/adma.201707100).