Selective localization of nanoparticles in microstructured systems

The research activities carried out during the doctoral program focused on selective localization of nanoparticles in microstructured polymer systems. Three distinct processes, very different from each other, were employed to achieve similar results. The first area of research has involved the selective localization of the carbon nanotubes within a biphasic and bicontinuous blend of polystyrene and polylactic acid, obtained by melt mixing the two thermoplastic polymers. Nanoparticles were selectively dispersed in the polystyrene phase achieving a lower percolation threshold than the initial one. In the second line of research, carried out in collaboration with the Soft Matter Physics group of the Adolphe Merkle Institute (Fribourg, Switzerland), hybrid organometallic perovkite nanocrystals were produced by precipitation in liquid phase. These nanocrystals were then incorporated into a thin film of polyethylene glycol diacrylate deposited by spin-coating on a glass substrate. The polymer crosslinking, triggered by exposure to an oxygen plasma, induced the formation of corrugations on the film surface (wrinkles) allowing the microstructuring of the perovskite. In the third line of research, carried out in collaboration with the National Institute of Optics (INO-CNR), selective localization of quantum dots in polydimethylsiloxane microlenses on a pyroelectric lithium niobate substrate were achieved through electrohydrodynamic and dielectrophoretic mechanisms. The lithium niobate substrate was periodically poled in an hexagonal pattern using finite element simulations to predict the final position of particles.