John B. Wiley at the University of New Orleans is supported by an award from the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry to investigate an unusual motif in chemical structures on the scale of nanometers (billionths of a meter). The ability to organize small scale objects (nanoobjects) into ordered arrays is important to the development of new technologies. In this project, new peapod-like structures are assembled from small spheres and very thin sheets. The materials are then studied in terms of methods of assembly, variations in composition, and physical properties. Such materials are of interest in that they could lead to important technological advances in a variety of areas including magnetics, electronics, photocatalysis, and drug delivery. Undergraduate and graduate students are involved in all aspects of the research component of this program, providing them with valuable training in the synthesis and characterization of new nanostructures as well as the presentation and publication of scientific data. There are also undergraduate students from France who come to work in the research group's laboratory, promoting chemistry at the international level. Finally, to help promote science in the New Orleans area, local high school students are involved in this research program each summer.
The ability to form nanopeapod structures by the capture of nanoparticles in scrolled nanosheets offers a new approach to the assembly of 1-D nanostructures. This project focuses on those aspects of nanoparticle assembly and nanosheet scrolling specifically important to the formation of extended peapod nanostructures. The program involves a combination of synthesis/assembly, characterization, and mechanistic studies. The goals of this effort are to 1) better understand and control the assembly of nanopeapod structures, 2) utilize peapod assembly in directing the formation of intricate composites, 3) extend these efforts to other host materials known to form scrolls, and 4) examine the prospect of reversibility in these assembly processes. Understanding of the assembly process is being pursued through, for example, investigations of its size and shape selectivity. Other advances are being developed through property tuning (magnetic, optical and/or electronic) in mixed nanoparticle assemblies. While the earliest investigations of the group were based on hexaniobate nanosheets, new scroll components are being sought, including isostructural tantalates, layered perovskites, transition metal dichalcogenides and graphene. Reversibility in scrolling of these structures is being examined as part of a 'capture-release' concept in nanoassembly.
