Graphene Cracks the Glass
Corrosion Problem
Researchers at the Center for
Multidimensional Carbon Materials (CMCM), within the Institute for Basic Science (IBS) have
demonstrated graphene coating protects glass from corrosion. Their research,
published in ACS Nano, can contribute to solving
problems related to glass corrosion in several industries.
Glass has a high degree of both corrosion and chemical
resistance. For this reason it is the primary packaging material to preserve
medicines and chemicals. However, over time at high humidity and pH, some glass
types corrode. Corroded glass loses its transparency and its strength is
reduced. As a result, the corrosion of silicate glass, the most common and
oldest form of glass, by water is a serious problem especially for the
pharmaceutical, environmental and optical industries, and in particular in hot
and humid climates.
Although there are different types of glass, ordinary
glazing and containers are made of silicon dioxide (SiO2), sodium
oxide (Na2O) along with minor additives. Glass corrosion begins with
the adsorption of water on the glass surface. Hydrogen ions from water then
diffuse into the glass and exchange with the sodium ions present on the glass
surface. The pH of the water near the glass surface increases, allowing the
silicate structure to dissolve.
Scientists have been looking at how to coat glass to
protect it from damage. An ideal protective coating should be thin,
transparent, and provide a good diffusion barrier to chemical attack. Graphene
with its chemical inertness, thinness, and high transparency makes it very
promising as a coating material. Moreover, owing to its excellent chemical
barrier properties it blocks helium atoms from penetrating through it. The use
of graphene coating is being explored as a protective layer for other materials
requiring resistance to corrosion, oxidation, friction, bacterial infection,
electromagnetic radiation, etc.
IBS scientists
grew graphene on copper using a technique previously invented by Prof. Rodney
S. Ruoff and collaborators, and transferred either one or two atom-thick layers
of graphene onto both sides of rectangular pieces of glass. The effectiveness
of the graphene coating was evaluated by water immersion testing and observing
the differences between uncoated and coated glass. After 120 days of immersion
in water at 60°C, uncoated glass samples had significantly increased in surface
roughness and defects, and reduced in fracture strength. In contrast, both the
single and double layer graphene-coated glasses had essentially no change in
both fracture strength and surface roughness.
“The purpose of the study was to determine whether
graphene grown by chemical vapor deposition on copper foils, a now established
method, could be transferred onto glass, and protect the glass from corrosion.
Our study shows that even one atom-thick layer of graphene does the trick,”
explains Prof. Ruoff, director of the CMCM and Professor at the Ulsan National Institute of Science and Technology
(UNIST). “In the future, when it is possible to produce larger and yet
higher-quality graphene sheets and to optimize the transfer on glass, it seems
reasonably likely that graphene coating on glass will be used on an industrial
scale.”
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Afterword by the Blog Author
It does not appear clear to me whether or not this graphene
coating makes borosilicate laboratory glass obsolete. High temperature laboratory glass might
remain preferable for work in a chemistry lab or for long term storage of
extremely toxic materials. See this
link:
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