[Image above] Credit: NASA’s Marshall Space Flight Center; Flickr CC BY-NC 2.0
Space is awash with UV radiation.
There’s so much radiation spewing from space—originating from the sun and other astronomical objects—that even here on earth, under the protection of our hospitable protective atmosphere, UV radiation is still strong enough to damage the DNA within our cells.
In space, the damaging effects of radiation are intense. Radiation is energy, after all—it creates defects in materials, altering the material’s properties.
So it’s perhaps no surprise that radiation causes a lot of problems for spacecraft, spanning from gradual performance degradation to downright device failure.
Protection from those levels of radiation is a big obstacle in making human endeavors like that portrayed in The Martian a reality. But protection is also an obstacle when it comes to sensitive exterior equipment aboard even unmanned spacecraft, including electronics.
Which is why researchers at Zhejiang University and South China University of Technology in China are excited that they have created new glass-based composite materials that are really good at absorbing UV radiation.
The transparent material, made of cerium (IV) oxide, can block UV and withstand prolonged UV radiation without degrading. Beyond being well-suited to protect electronics in space, the material could be used to protect living cells against damaging radiation here on earth, too.
According to a press release from The Optical Society about the research, now published in Optical Materials Express, the transparent glass-ceramic can prevent the separation of electrons and holes that happens in a material in response to light radiation, slowing overall material breakdown.
Image of an active Sun in 3-D. Credit: NASA’s Solar Dynamics Observatory; Flickr CC BY-NC 2.0
The scientists fabricated the materials using a sol gel method already used to make other metal oxide UV absorbers, including those composed with zinc and titanium oxides.
To create the glass, scientists first evolved the material as a sol and then dessicated it slowly—over weeks—to transform the material into a gel. Drying the gel to evaporate remaining liquid revealed a glass material, which the researchers finally heat-treated.
The researchers say that the key to the material’s radiation-busting abilities is its self-limiting nanocrystallization when produced with this method.
“Self-limited nanocrystallization of glass can be achieved by taking advantage of the rigid environment of the solid-state matrix, rather than the conventional solution and vapor conditions to modulate the ionic migration kinetics,” author Shifeng Zhou says in the OSA release. “It allows us to create glass-ceramics embedded with a CeO2:fluorine nanostructure.”
The release continues, “The viscous glass matrix involved poses a considerable constraint for oxide and fluoride-ion diffusion, so the group gradually etches trifluorocerium (CeF3) by oxide ions within an oxide matrix until fluoride-doped CeO2 is generated in a controllable manner.”
Importantly, the researchers point out that their work establishes a method for functionalization of glass via microstructure engineering, an accomplishment that could bleed into new materials for additional applications, too.
“Our glass shows excellent optical quality, and it can be easily fabricated either in bulk form or as a film,” Zhou says in the release. “It effectively protects organic dye and living cells from UV radiation damage.”
In the paper, the authors write that in addition to biological protection and space electronics, the glassy materials could also preserve cultural relics.
“We’ll explore ways for large-scale fabrication of this type of film, which is extremely important for practical applications,” Zhou says in the release. “Our group will also further study the functionalization of glass based on its microstructure engineering, because we believe this fundamental research may have great significance for the glass industry.”
The paper, published in Optical Materials Express, is “Glass composite as robust UV absorber for biological protection” (DOI: 10.1364/OME.6.000531).