Spatiotemporal Studies of Soluble Inorganic Nanostructures with X‐rays and Neutrons

Abstract

This review addresses the use of X‐ray and neutron scattering and X‐ray absorption to describe how inorganic nano‐structured materials assemble, evolve, and function in solution. We first provide an overview of techniques and instrumentation (both large user facilities and benchtop). We review recent studies of soluble inorganic nanostructure assembly, covering the disciplines of materials synthesis, processes in nature, nuclear materials, and the widely applicable fundamental processes of hydrophobic interactions and ion‐pairing. Reviewed studies cover size regimes and length scales ranging from sub‐angstrom (coordination chemistry and ion‐pairing) to several nanometers (molecular clusters; i.e. polyoxometalates, polyoxocations and metal‐organic polyhedra), to meso‐scale (supramolecular assembly processes). Reviewed studies predominantly exploit 1) SAXS/SWAXS/SANS (small and wide angle X‐ray or neutron scattering), 2) PDF (pair distribution function analysis of X‐ray total scattering), and 3) XANES and EXAFS (respectively X‐ray absorption near edge structure and extended X‐ray absorption fine structure). While the scattering techniques provide structural information, X‐ray absorption yields oxidation state, in addition to local coordination. Our goal for this review is to provide information and inspiration for the inorganic/materials science communities that may benefit from elucidating the role of solution speciation in natural and synthetic processes.

Unique Viscoelasticity and Hierarchical Relaxation Dynamics of Molecular Granular Materials

“…Small angle X-ray scattering (SAXS) provides access to the structure of PolyPOSS-1 in the bulk. 36 The highly branched feature of the pendant POSSs prevents the ordered packing among the brush assemblies, giving rise to the amorphous structures of PolyPOSS bulks. Compared with the scattering curve of OPOSS-Vinyl, the second scattering maximum at 0.51 Å −1 informs an average separation distance of 1.2 nm between the packed POSS units (Figure 1d).…”

“…The successful preparation of PolyPOSS-1 is proven by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) data (Figure c and Figure S1). Small angle X-ray scattering (SAXS) provides access to the structure of PolyPOSS-1 in the bulk . The highly branched feature of the pendant POSSs prevents the ordered packing among the brush assemblies, giving rise to the amorphous structures of PolyPOSS bulks.…”

Exploration of Molecular Nanoparticles as Soft Structural Materials and Their Structure–Property Relationship

“…The successful assembly of the star-shaped MNPs is confirmed by gel permeation chromatography (GPC, Figure S1), dynamic light scattering (DLS, Figure S2), Fourier transform infrared spectroscopy (FT-IR, Figure S3), and UV absorption data (Figure S4). The fine structures of individual MNP can be precisely determined via small-angle X-ray and neutron scattering (SAXS and SANS) measurements 36 (Figure 2a and Figure 2b). The scattering data of MNP-1 to MNP-3 can all be fitted well by the core−shell sphere model.…”