title: Following in Real Time the Two-Step Assembly of Nanoparticles into Mesocrystals in Levitating Drops.
abstract: Mesocrystals composed of crystallographically aligned nanocrystals are present in biominerals and assembled materials which show strongly directional properties of importance for mechanical protection and functional devices. Mesocrystals are commonly formed by complex biomineralization processes and can also be generated by assembly of anisotropic nanocrystals. Here, we follow the evaporation-induced assembly of maghemite nanocubes into mesocrystals in real time in levitating drops. Analysis of time-resolved small-angle X-ray scattering data and ex situ scanning electron microscopy together with interparticle potential calculations show that the substrate-free, particle-mediated crystallization process proceeds in two stages involving the formation and rapid transformation of a dense, structurally disordered phase into ordered mesocrystals. Controlling and tailoring the particle-mediated formation of mesocrystals could be utilized to assemble designed nanoparticles into new materials with unique functions.
authors: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden.
authors: Michael
authors: M
authors: Agthe
authors: MAX IV Laboratory, Lund University , P.O. Box 118, SE-22100 Lund, Sweden.
authors: Tomás S
authors: TS
authors: Plivelic
authors: MAX IV Laboratory, Lund University , P.O. Box 118, SE-22100 Lund, Sweden.
authors: Ana
authors: A
authors: Labrador
authors: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden.
authors: Lennart
authors: L
authors: Bergström
authors: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University , S-106 91 Stockholm, Sweden.
authors: German
authors: G
authors: Salazar-Alvarez
keywords: Mesocrystal; SAXS; acoustic levitation; anisotropic nanoparticles; two-step crystallization