Francesco Stellacci, MITFrom Nanoparticles to NanoPolymersAbstract:In this talk we will show that when mixed self-assembled monolayers (SAMs) are formed on surfaces with a radius of curvature smaller than 20 nm they spontaneously phase-separate in highly ordered phases of unprecedented size. The reason for this supramolecular phenomenon is purely topological and can be rationalized through the "hairy ball theorem". In the specific case of mixed SAMs formed on the surface of gold nanoparticles, the molecular ligands separate into 5 Å wide phases of alternating composition that encircle or spiral around the particle metallic core. This new family of nano-structured nano-materials shows new properties solely due to this novel and unique morphology. For example, particles’ solubility starts to depend on the ratio between the dimensions of the phases and that of the solvent molecules. More importantly, chains of these particles can be efficiently assembled, possible optical application of these chains will be discussed. BiographyFrancesco Stellacci graduated the Politecnico di Milano in 1998 with a thesis on photochromic materials. He then moved to the University of Arizona as a post-doctoral scholar and worked on two-photon microfabrication of three dimensional metallic structures. In September 2002 he was appointed as Assistant Professor of Materials Science at MIT.
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