Perfect crystalline layers

They soak like sponges: MOFs (Metal-Organic Frameworks) are highly porous material powders able to accommodate molecules or nanoparticles. This property makes MOFs attractive in many areas of use. They can accommodate gases, such as hydrogen or methane, in this way serving as energy stores. In medicine, MOFs can also act as drug depots.

State of the art

It is possible technically to produce MOFs as powders with a perfect three-way crystal lattice structure. On the other hand, these material powders are of limited use in specific applications, such as molecule separation.

Technology

Scientists at the KIT Institute of Functional Interfaces (IFG) have now found a possibility to manufacture MOFs bound to surfaces. These so-called SURMOFs (Surface-Anchored Metal-Organic Frameworks) may be applied both to plane substrates and to micro- or nanoparticles. In either case, perfect crystalline MOF layers are produced. As in a model toy kit, the layer-by-layer technique results first in metal nodes and then in organic struts (so-called linker molecules) being applied to the surface. These building blocks combine into highly crystalline frameworks by self-arrangement. The lengths and types of linker molecules determine the size and the physical and chemical properties of the pores.

Advantages

The separation process can be repeated until the desired thickness of the SURMOF layer has been achieved. In this way, SURMOFs with tailored properties can be produced. Moreover, magnetic carrier material can be used, such as nanoparticles of iron oxide. In this way, the particles can be collected by means of a magnetic field and re-used after application.

Options for companies

SURMOFs have a high potential for application, especially in separating molecules, as gas stores, and in sensors and photovoltaics. The KIT is looking for partners interested in implementing this technology in the field.