Ordered metal oxide nanoparticles in thin polymer films

Prof. Dr. Peter Müller-Buschbaum

Nano-composite materials based on a polymer matrix and inorganic metal oxide nano-particle fillers mark a new class of magnetic materials. This class of soft matter based hybrid materials (SMBH) envisages novel electrical, optical and magnetical properties due to the possibility to create structures which are inaccessible with traditional hard matter materials. Of special interest are thin nano-composite films from this class, which can be candidates for future applications in various fields such as electronics, opto-electronics and magnetics.

In SMBH, the polymer matrix acts as a structure directing agent, which allows for the control of the position of the nanoparticles (see figure). We will use block copolymers which are well known to exhibit structure formation by micro phase separation. Depending of control parameters of the block copolymer such as block ratio, molecular weight and incompatibility between the blocks different nanoscale morphologies (spheres, cylinders, gyroids or lamellae) are installed. In our special approach, the surface of the nanoparticles is coated with polymer molecules or functional groups to allow for an embedding (see figure). The used coating of the nanoparticles is equal to one of the parts of the copolymer which allows the nanoparticles to self-assemble and organize themselves selectively in one block. Nanoparticles with diameters on the order of 10 nanometer are easily embedded in case this length is small as compared to the morphological length scales (e.g. lamellar spacing) introduced by the block copolymer.