The 3D structure
of the metal-organic framework used in this study.
The nanopores are
represented as yellow balls.
(December 14, 2015) Metal-organic
frameworks (MOFs) are a new type of materials with nanoscale pores. Bioscience
engineers from KU Leuven have developed an alternative method that produces
these materials in the form of very thin films, so that they can easily be used
for high-tech applications such as microchips. The study was published in
Nature Materials.
Metal-organic frameworks (MOFs) are a recently developed
type of materials that consist of a nanoporous grid of both organic molecules
and metal ions. MOFs take shape as the organic molecules push the metal ions
apart, so that a regular pattern of tiny holes or nanopores develops.
The size of the pores can be tuned at the nanoscale level
(with a nanometre being a billionth of a metre). The internal surface of an
MOF, formed by all these pores, varies in size from 1,000 to 5,000 square
metres per gram of material. MOFs can be seen as microscopic sponges that can
absorb a lot of material.
This property makes MOFs interesting in terms of
applications. “Researchers are already looking into these applications”, says
Professor Rob Ameloot from the KU Leuven Centre for Surface Chemistry and
Catalysis. “They are examining the use of MOFs as catalysts to accelerate
chemical reactions of guest molecules in the MOF pores. Another possible application
is gas storage, as the internal surface of MOFs can hold large amounts."
"So far, some applications were not considered feasible
due to the production procedure for MOFs. The conventional method involves
lab-scale wet chemistry – the traditional chemistry with solutions and
solvents. The end result is a powder. For integrated, nanoscale applications,
the particles of that powder are too large, while a method with solutions is
not pure enough. In the case of gas sensors, for instance, the MOF material has
to be deposited as a thin film over the surface of the electrical circuit. That
is not possible if you use the conventional production procedure.”