Well-Controlled Preparation Of Polymeric Micelles With An Aqueous Core And Self-Assembly Of Polymeric Nanoparticles

Recently, block copolymer micelles have drawn great research interest because of their wide applications in the areas of microreactors, drug delivery and catalysis. Meanwhile, assemblies of colloidal particles are paid more and more attention, due to their distinctive principles and potential applications in material science. The work of this thesis are summarized as two following parts:1. HC1 aqueous/PS-b-P4VP chloroform solution biphase system was constructed to induce the micellization of PS-b-P4VP in chloroform phase. As the process of HCl-transfer from aqueous phase to chloroform phase is slow and steady, the micellization is well controlled. Monodispersed polymeric micelles with an aqueous core (PMACs) were prepared via further accumulation of water molecules in the core of micelles. We carefully studied the whole processes of micellization and PMAC formation with DLS, ¹H NMR and TEM.Various inorganic nanoparticles, including SiO₂, Fe(SCN)²⁺, AgCl and Ag₂ClNO₃ nanoparticles were prepared in PMAC microreactors, via sol-gel, coordination, chemical precipitation and photochemistry methods. As microreactors, PMACs combine the advantages of surfactant micelles and traditional block copolymer micelles. On one hand, similar to surfactant micelles, the aqueous core of PMACs can load all hydrophilic precursors; on the other hand, block copolymers provide good stability to the formed inorganic nanoparticles and make them disperse in low polar medium, which enlarges their application scope. 2. PS/P4VP heteroarm polymeric nanoparticles with long PS arms and short P4VP arms were prepared via two-step anionic polymerization. In common solvent DMF and selective solvent toluene for the PS arms, polymeric nanoparticles existed as single particles. While in acidic water, the selective solvent for P4VP arms, the polymeric nanoparticles self-assembled into spherical superparticles through the hydrophobic interaction of PS arms. Heteroarm polymeric nanoparticles in toluene and superparticles in acidic water were employed as templates to prepare gold nanoparticles clusters with different morphologies. In toluene, within single particle templates, raspberry-like gold nanoparticle clusters were obtained. In acidic water, we can control the morphologies of gold/superparticle hybrids by adjusting the solvent composition. In 0.1 M HCl, the gold nanoparticles in superparticles formed shell-like clusters; in 0.1 M HC1/DMF (9/1, v/v) , dendron-like cluster were formed.