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The self-assembly of strongly-coupled nanocrystal superlattices, as a convenient bottom-up synthesis technique featuring a wide parameter space, is at the forefront of next-generation material design. To realize the full potential of such tunable, functional materials, a more complete understanding of the self-assembly process and the artificial crystals it produces is required. In this work, we discuss the results of a hard coherent X-ray scattering experiment at the Linac Coherent Light Source, observing superlattices long after their initial nucleation. The resulting scattering intensity correlation functions have dispersion suggestive of a disordered crystalline structure and indicate the occurrence of rapid, strain-relieving events therein. We also present real space reconstructions of individual superlattices obtained via coherent diffractive imaging. Through this analysis we thus obtain high-resolution structural and dynamical information of self-assembled superlattices in their native liquid environment.
There has been a recent push to examine the materials that nature is able to synthesize and consider whether the materials that humans have invented are geomimetic in nature, and whether designing nature-inspired materials is economically and environmentally beneficial. Mesoporous silica represents a class of materials with pore sizes of 2-50 nm and has been studied in catalysis, separations, and drug delivery. It has generally been made using organosilicon precursors, but in this work, we demonstrate for the first time the successful synthesis of mesoporous silica with uniform mesoporosity of 10 nm using the mineral forsterite (Mg2SiO4) as a silica source, providing a potentially cheaper and more Earth-friendly route to making this technologically important material. Forsterite was synthesized by a solid-state chemistry route and underwent dissolution-reprecipitation in an aqueous acid solution containing the soft template surfactant, Pluronic P123. The formation of forsterite was confirmed with X-ray diffraction (XRD), the successful templating of surfactant was demonstrated with thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR), the surface area was determined through Brunauer-Emmett-Teller (BET) analysis, and pore size and distribution were demonstrated with Barrett-Joyner-Halenda (BJH) analysis. The synthesized mesoporous silica at optimal conditions has surface area of 740 m2/g and pore volume of 1.4 mL/g.