Jones, Matthew R2024-01-242024-01-242023-122023-09-05December 2Gerrard-Anderson, Theodor Maxwell. "The Controlled Deformation and Assembly of Anisotropic Nanostructures." (2023). PhD diss., Rice University. https://hdl.handle.net/1911/115381https://hdl.handle.net/1911/115381The desirable properties of inorganic nanostructures are, in large part, determined by their morphologies, whether it be their plasmon resonance, surface chemistry, or assembly behavior. Therefore, great effort has been expended over the last two decades into growing the library of available inorganic nanostructures, primarily through the development of more sophisticated synthetic techniques utilizing directing ligands and differing facet reactivity. Particularly sought after are methods to fabricate low symmetry nanostructures, as these frequently exhibit more exotic properties, such as optical chirality, or the ability to organize into highly anisotropic superlattices with unique crystal habits and lattice structures. The difficulty in fabricating low symmetry inorganic nanostructures originates in the inherent isotropy of the chemical conditions used to grow them, forcing these methods to rely on the inherent asymmetry of a given material’s crystal structure or that imposed by carefully chosen directing ligands. As such, these protocols are designed ad hoc for each material, leading to a gradual expansion of available morphologies over time. The mechanical deformation of inorganic nanostructures is a promising route toward accessing novel low symmetry morphologies and a rapid expansion of the existing library. Mechanical deformation involves the imposition of an anisotropic force onto a nanostructure, leading to bending strain and a lower symmetry product. We have recently developed a method of inorganic nanostructure deformation wherein a template particle is used to direct the shape change. In this method, noble metal nanoplates are deposited onto spherical template particles and deform to their shapes due to cumulatively strong Van der Waals interactions across the large surface area of the nanoplate. In this work we demonstrate templated deformation of micron sized silver nanoplates over 15 nm template particles, characterizing their morphology through transmission electron microscopy and producing a Kirchhoff-Love theory derived analytical model to elucidate the relationship between nanoplate thickness and final deformation morphology and demonstrate that Van der Waals forces are sufficient to induce plastic deformation in the nanoplate. We extend this model to show the effect binding ligands have on the overall mechanical properties of thin silver nanoplates and demonstrate this method could be applied to other materials. We also develop a synthesis for high aspect ratio gold nanoplates and show that their deformation around template particles on the same order of size yields high morphological diversity in the products, as well as curvature control which can be exerted by altering the size of the template particle. Using a combination of cross-section TEM imaging, chemical nanoplate overgrowth experiments, and tomographic reconstruction, we show the nanoplates are deformed elastically and accurately measure their curvature landscapes. Finally, we develop a method for the functionalization of 2 nm wide and ~1 micron long ultra-thin gold nanowires, desirable for their simultaneous flexibility and electrical conductivity, with a stimulus responsive thiol ligand based on carboxyl group chemistry. The ultra-thin gold nanowires assemble and disassemble in response to specific chemical stimuli and can be assembled into macroscopic fibers, demonstrating preliminary work that could be continued to develop fibers of these functionalized ultra-thin gold nanowires as functional materials. Overall, this work breaks new ground on the use of deformable and flexible nanostructures in generating low symmetry morphological diversity and functional anisotropic superstructures.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.MechanicalDeformationNanostructureInorganicThesis2024-01-24