The Preparation Of Binary Superpaticles Via Solvophobic Interactions

Colloidal superparticles are nanoparticle assemblies in the form of colloidal particles. The assembly of nanoparticles into macroscopic complex architectures allows bottom-up fabrication of functional materials.In the past decades,efforts have been focused on the preparation of nanoparticle superlattices with various compositions and supercrystalline structures. Recently, several approaches have been reported for making nanoparticle superlattices in the form of colloidal particles. These SPs are spheres with well-controlled sizes ranging from tens to hundreds of nanometers, and their properties can be tailored by varying the size, composition and surface of the nanoparticle building blocks.In our studies,we adopt a template-free method to prepare binary superlattice via solvophobic interactions,and the obtained superlattice shows excellent stability in polar solvents.In the second chapter, binary superlattice consisting of6nm and12nm OA modified Fe3O4nanaparticles were obtained via solvophobic interactions.Firstly, water-soluble Fe3O4nanoparticle micelles were obtained,driven by the hydrophobic van der Waals interactions between the hydrocarbon chain of the OA and the hydrocarbon chain of the DTAB; after evaporating the solvent,the nanoparticle-micelles were introduced into an ethylene glycol solution,as the van der Waals interactions between nanoparticle ligands and surfactants were weakened,the nanoparticle-micelle lose the DTAB,and the solvophobic interactions between the nanoparticle ligands and ethylene glycol solution induced the the formation of SPs. We analyse the effects of the concentration of Fe3O4nanoparticles in oil phase and DTAB in water phase on the size of Fe3O4superparticles. By varying the concentration ratio of the6nm:12nm Fe3O4nanaparticles.a series of Fe3O4binary superlattice were abtained. SAXS measurements showed that the assemblies made of6nm、12nm adopt an fcc superlattice structure.the assemblies with6nm:12nm concentration ratio-1:13and1:4, while the assemblies with6nm:12nm concentration ratio-1:1possess a bcc structure. With the increase of mole ratio of12nm Fe3O4nanaparticles within the superlattice, the lattice constant (a) shows nearly linear change which obeys the Vegard’s Law. The superparticles abtained were superparamagnetic, with its highest saturation magnetizations of60emu/g.with6nm:12nm concentration ratio-1:1Using similar route, we obtained several kinds of superlattice from monodisperse CdSe and CdSe/ZnS nanoparticles. Further studies indicates that the emissive efficiency of CdSe/ZnS superlattice can be almost two times higher than the nanoparticles,while the CdSe superlattice shows nearly no PL.Further more, we attempt to use3nm CdSe and6nm Fe3O4nanaparticles to prepare binary superparticles via solvophobic interactions,which proves it can be extended for the self-assembly of two or more types of nano-objects into well-defined mesoscopic and macroscopic complex architectures.