If you were to advertise so-called COFs in a commercial, the slogan would be something like: “The airy, light miracle sponge for all needs.” Because this porous material cleans, separates and stores gases and liquids. In addition, it acts as a catalyst for chemical reactions. COF stands for Covalent Organic Framework. The basic building blocks of the material are hexagons of organic molecules that arrange side by side to form a single layer. Stacked on top of one another, the layers form an extensive three-dimensional network that is very stable even at relatively high temperatures due to the covalent bonds between the molecules in the layer plane.
The main reason that COF materials are so popular is that chemists can adjust their properties during synthesis with a high level of control. These include the pore size, shape or distribution of functional groups. Only the stacking of the individual layers does not always go according to plan: They are often placed above one another not exactly, but with a slight offset. This frustrates the experts, because even small deviations unintentionally change the structure of the surface and channels and make access to functional groups more difficult.