This project, supported by the Solid State and Materials Chemistry (SSMC) program at NSF, will investigate the formation, structure-magnetic property correlation of the ultrathin (diameter, d < 4 nm), one dimensional magnetic nanowires. It will further explore their potential as effective contrast agents for magnetic resonance imaging (MRI). In this CAREER proposal, a new "selective heating" method for the synthesis of ultrathin magnetic ferrite nanowires will be explored. The key principle to this new approach is to selectively decompose certain ligands of the precursor complex based on an understanding of the precursor chemistry, creating a ligand soft template for ligand-directed growth. The unique spinel structure of ferrite nanowires makes doping an important parameter to tune their magnetic properties. Therefore, doping effects on the morphology, structure, and magnetic property of the ultrathin nanowires at extremely small scale will be systematically investigated. Finally, the relaxivity of ultrathin iron oxide and doped ferrite nanowires will be evaluated and further correlated with their structures and morphologies, establishing a link among synthesis-structure-property-relaxivity. The relaxivity is a key parameter to evaluate the effectiveness of a contrast agent in MRI. The proposed studies will significantly advance the field by unraveling the essential knowledge and design rules for synthesizing ultrathin nanowires with controlled structural and magnetic properties for various applications.
NON-TECHNICAL SUMMARY: The proposed studies will significantly advance our fundamental understanding of a new wet chemistry approach to the synthesis of ultrathin nanowires. The developed synthetic strategies and the underlying mechanisms can be readily extended to the fabrication of other nanomaterials with similar dimensions. Beyond bioimaging, these ultrathin magnetic ferrite nanowires have great potential in gas sensing, photocatalysis, spintronics, and energy. The impact of this CAREER proposal will be further enhanced through several educational and outreach activities, including: (1) initiating a "Science Party for Kids" program with a local (Rock Quarry) Elementary School to introduce science and engineering concepts to students early; (2) promoting participation of underrepresented groups in nanomaterials through research programs, lectures, scientific demonstrations, and professional societies; (3) generating and disseminating new scientific knowledge resulting from this CAREER proposal through several avenues, such as peer-reviewed publications, seminars, conference presentations, teaching, summer school lectures, and websites.
