For many applications, nanoparticles need to be provided as dispersions. Hence, their stabilization against agglomeration is of utmost importance. Whilst the classical colloidal methods involve either charge stabilization or the adsorption of polymers to the particle surface, nanoparticles can often also be stabilized by the adsorption of small organic molecules. This “small-molecule stabilization” is commonly employed in nanomaterials synthesis and processing, but yet there is a lack of fundamental understanding of the underlying fundamentals and mechanisms for particles below 100 nm in size.
This research project aims at an elucidation of small-molecule stabilization especially of small nanoparticles < 10 nm in size. Using model systems with monodisperse nanoparticles, the interrelation between the adsorption of the stabilizer and the deagglomeration of the nanoparticles is explored. A special focus of the project is the influence of solvent compatibility of the stabilizer on the stabilization in diverse media, as well as investigations on the long-term stability. The experimental results are complemented by theoretical calculations of the interaction energies between the particles based on DLVO, XDLVO and steric interaction theories. The project is funded by Deutsche Forschungsgemeinschaft within the framework of SPP 1273 “Colloids processing”.
ITO nanoparticles in chloroform left – stabilized, right – unstabilized
Publications:
[1] G. Garnweitner, Small molecule stabilization: A novel concept for the stabilization of small inorganic nanoparticles, in: L. Segewicz and M. Petrowsky (Eds.), Polymer Aging, Stabilizers and Amphiphilic Block Copolymers, Nova Science Publishers, 2010.
[2] G. Garnweitner, H. O. Ghareeb, C. Grote, “Small-molecule in situ stabilization of TiO2 nanoparticles for the facile preparation of stable colloidal dispersions”, Colloids and Surfaces Part A: Physicochemical and Engineering Aspects 2010, 372, 41-47.