CdS nanocubes formed in phosphatidylcholin-based template phases

The paper is focused on the characterization and use of phosphatidylcholine (PC)-based inverse microemulsions as a template phase for the CdS nanoparticle formation. The optically clear, isotropic phase in the oil corner was identified as a “classical” water-in-oil microemulsion by means of NMR-diffusion measurements. Because of the very small dimensions of the water droplets, the isotropic phase shows a Newtonian-like flow behavior, and adequate amounts of bulk water cannot be detected by DSC.It is demonstrated that this w/o microemulsion can be used successfully as a nanoreactor for the formation of CdS nanoparticles with diameters of 4–5 nm. During the following process of solvent evaporation the individual small CdS nanoparticles aggregate to significant larger cubic nanoparticles, with an edge length of 20–40 nm, arranged in well-defined mosaic-like superstructures. In presence of SDS the nanocubes were stable up to 800 °C. It has to be stated here that polyelectrolytes prevent the formation of such well-ordered superstructures.