Fraunhofer Institute for Interfacial Engineering and Biotechnology IGBWe have developed a variety of different polymers for the wet chemical coating of membranes. These polymers are thermally or photo-chemically cross-linkable and therefore the resulting coatings are long term stable. The properties are ranging from hydrophilic to hydrophobic and also functional groups (e.g. amines) can be introduced which are good starting points for a further chemical modification.
We have the infrastructure to make continuous roll-to-roll coatings both for hollow fiber and flat membranes. By controlling the wetting of the membranes it is possible to control whether the coating is on the surface of the membrane or inside the pores. In addition, there are coating systems available which are also suitable for a coating inside hollow fibers. Besides the coating with polymers other technologies, like interfacial polymerization or grafting-from are also available. Doing so thin film composite membranes are available with favorable properties for forward osmosis applications.