While the properties of most synthetic materials are persistently specified, many biological systems are able to adapt to changing environmental conditions. In analogy to such behavior, for several years researchers try to develop materials whose properties can be "switched" by external stimuli. They are called "smart" materials. As switches, many physical or chemical stimuli come into consideration, such as light, temperature, pH ot complex chemical reactions. Water-soluble polymers offer unique opportunities in this area, not least because they sometimes behave counter-intuitive. Thus, many uncharged polymers dissolve in water at low temperature but precipitate at increased temperature. Such a miscibility gap can be specifically used for switching: a temperature change of only a few degrees can completely change the property profile of a polymer. We are currently investigating possible applications of such reversibly switchable polymers, for example, in hydrogels on surfaces or emulsifiers.
Well-defined macromolecular structures
Block copolymers consisting of a nonionic block and a cationic block are able to complex the negatively charged backbone of the DNA. We examine whether such complexes can be used as non-viral gene vectors.
Supramolecular self-assembly of macromolecules
We study the self-assembly of amphiphilic block copolymers in aqueous media. These form various morphologies, such as simple micelles, vesicles or multicompartment micelles. Such nanostructures are interesting, for example as vehicles for drug delivery applications.
We develop colloids with tailored properties, such as monodisperse ferrofluids for use in magnetic resonance imaging. These colloids include inorganic particles of magnetite coated with molecular invisibility cloaks (diblocks of synthetic polymers and polypeptides).