CAREER: Synthesis of Polymer Coated Magnetic Colloids and Assembly into Mesoscopic Nanoparticle Chains

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TECHNICAL SUMMARY:The proposed research will focus on the development of a novel class of organic/inorganic hybrid nanoparticles as building blocks for hierarchically self-assembled materials. The fundamental aspects of the synthesis, characterization and assembly of polymer coated magnetic nanoparticles will be the focus of this proposal. The intellectual merit of the proposed research is the ability to prepare complex composite materials possessing controlled structure on molecular, nano- and mesoscale regimes. The development of a versatile synthetic methodology to prepare a library of functional ferromagnetic colloids will be initially pursued. Central to this approach is the use of well-defined polymers to prepare and functionalize ferromagnetic nanoparticles that are capable of 1-D magnetic assembly. Controlled radical polymerization will be central in the design and synthesis of polymeric surfactants. A second critical effort that will be investigated is the controlled assembly of functional ferromagnetic nanoparticle on surfaces, in solution and in polymer thin films. The effect of particle size, magnetization and applied magnetic fields will be investigated to determined optimal conditions for 1-D assembly and alignment in various matrices. Development of these areas is anticipated to enable the assembly and covalent linkage of functional magnetic nanoparticles into permanently linked chains. These functional 1-D assemblies are expected to be mesoscale analogues to polymer chains. Characterization of these materials using various imaging techniques (e.g., AFM, TEM), thermal analysis and mechanical property evaluation will be conducted to ascertain structure-property correlations of assembled materials possessing different morphologies. NON-TECHNICAL SUMMARY:Organic polymers and metallic particles will be synthesized and combined to prepare core-shell composite materials possessing an organic shell with tunable composition and an inorganic magnetic core. These materials will be hybridized on the nanoscale as an approach to prepare novel materials with synergistic properties. The magnetic properties of the materials will be utilized to self-assemble these hybrid nanoparticles into fiber-like structures spanning microns on length. This work is anticipated to impact a number of areas in microelectronics and optoelectronic devices due to the ability to control structure over a broad range of length scales. The proposed research is highly interdisciplinary and offers opportunities for students at high school, undergraduate and graduate levels to appreciate the importance of polymers and nanomaterials. Integration of the proposed research with educational outreach will be achieved by the mentoring of high school students and teachers in research experiences carried out at the University of Arizona by the principal investigator. Research implemented by this student-teacher team will be disseminated by integrated interactions with undergraduate research programs on campus. Emphasis will be placed on the mentoring and development of students from under-represented minorities in Tucson.