“It has always been a big challenge to combine highly pure quartz glass and its excellent properties with a simple structuring technology,” says Dr Bastian Rapp, head of the NeptunLab interdisciplinary research group of KIT's Institute of Microstructure Technology (IMT). “Instead of heating glass up to 800°C for forming or structuring parts of glass blocks by laser processing or etching, we start with the smallest glass particles.”
The scientists mix glass particles of 40 nanometres in size with a liquid polymer and harden it to a solid by heating or light exposure. The resulting solid consists of glass particles in a matrix at a ratio of 60 to 40. The polymers act like a bonding agent that retains the glass particles at the right locations and maintains the shape.
This ‘Glassomer’ can be milled, turned, laser-machined or processed in CNC machines just like a conventional polymer. For fabricating high-performance lenses that are used in smartphones among others, the scientists produce a Glassomer rod, from which the lenses are cut. For highly pure quartz glass, the polymers in the composite must be removed. For doing so, the lenses are heated in a furnace at 500 to 600°C and the polymer is burned fully of CO2. To close the resulting gaps in the material, the lenses are then sintered at 1300°C, during which, the remaining glass particles are densified to pore-free glass.
This forming technology enables production of highly pure glass materials, for which only polymers have been suited so
far. This opens new opportunities for the glass processing industry as well as for the optical industry, microelectronics, biotechnology, and medical engineering. “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,” Dr Rapp explains.
KIT is planning to launch a spinoff company that will commercialise the Glassomer.