Synthesis and property investigations of well-defined polymer/inorganic core-shell nanomaterials with structural, optical, electronic and magnetic properties.

摘要

Polymer grafted inorganic nano-objects typically consist of an inorganic core with an end-grafted, tailored polymer shell. Herein described is the combination of magnetic, electronic, or optical properties of the inorganic core with the versatile mechanical and chemical properties of the polymer shell.; The synthesis, characterization and application of nanomaterials require interdisciplinary work. For example, Fe2O3/Poly(styrene) core-shell structures were synthesized using chemical analysis, characterized using physics and implemented as a magnetic resonance imaging (MRI) agent using biology. There are three structural components to the core-shell particles: the inorganic core, the interface and the polymer shell. The inorganic core can impart properties to the overall structure, such as photoluminescence, magnetism, and mechanical reinforcement, which cannot easily be obtained using just organic materials. The interface where the core and shell meet is another key component in the design of the core-shell nanoparticle. The polymeric shell must be tethered to the core for optimum stability of the structure and to overcome potential incompatibilities between the two phases. The distribution of polymeric initiators as tethers allowed for polymerization from the surface. The research described used "grafting from" methods by living polymerizations. The grafted polymer can add function to the overall hybrid, as chemical functionality in the side chains can assist in particle self-assembly or serve as a scaffold for the attachment of biological molecules. The polymer, itself, can serve as a protective barrier, a matrix for the composite, or a solubility/dispersibility enhancer. The effect of variations in the length of the polymer chains on mechanical and morphological properties was studied.; The research described herein will develop the ideas of core-shell structures: (1) in macro-scale synthesis and application of spherical silica particles in poly(methyl methacrylate) (pMMA) which can function as strength enhancers in a material, (2) as wave-guides in electro-optical applications by grafting a non-linear optical (NLO) molecule to a nano-sized core, (3) as a conductive medium by developing a conductive poly(thiophene) (pT) polymerization method to functionalize an core structure, and (4) as a nano-sized magnetic core encased in a well-defined poly(styrene) (pS) matrix.