Shape Induced Symmetry in Self-Assembled Mesocrystals of Iron Oxide Nanocubes

Abstract

Grazing incidence small-angle scattering and electron microscopy have been used to show for the first time that nonspherical nanoparticles can assemble into highly ordered body-centered tetragonal mesocrystals. Energy models accounting for the directionality and magnitude of the van der Waals and dipolar interactions as a function of the degree of truncation of the nanocubes illustrated the importance of the directional dipolar forces for the formation of the initial nanocube clusters and the dominance of the van der Waals multibody interactions in the dense packed arrays.

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

“…For example, (i) it has been demonstrated that T B can be easily increased by adding a surface layer of a hard material on a soft nanoparticle (soft/hard approach) [102,143,250], (ii) it has been shown that the coercivity (i.e., switching field) of hard nanoparticles is reduced when coupled to soft shells (hard/soft approach) [102,190], (iii) the possibility to form selfassembled arrays of core/shell nanoparticles [92][93][94]99,102,103,122,190,263,406] or (iv) possible graded anisotropy in core/shell nanoparticles [105]. Nevertheless, other critical features like large, defect free, self-assemblies of hard-soft core/shell nanoparticles (i.e., in the same range as the ones shown for single phase magnetic nanoparticles [407]) have not yet been demonstrated. In fact, although some types of inorganic core/shell nanoparticles have been shown to form well-ordered arrays [21], since as the shell is grown on the core the overall morphology can slightly deteriorate, consequently the self-assembly becomes increasingly difficult, as demonstrated in Fig.…”

Lyotropic Liquid Crystal to Soft Mesocrystal Transformation in Hydrated Salt–Surfactant Mixtures

“…[12][13][14][15][16][17][18][19] There are examples of mesocrystals ranging from biominerals to functional materials. [12] Mesocrystals are usually obtained by a self-assembly process of colloidal nanocrystals that are crystallographically oriented by surfactants and polymers in a superstructure and are usually solid materials.…”

“…[12] Mesocrystals are usually obtained by a self-assembly process of colloidal nanocrystals that are crystallographically oriented by surfactants and polymers in a superstructure and are usually solid materials. [12][13][14][15][16][17][18] Building blocks in these nonclassical crystals are usually nanomaterials with well-defined shape and size. [14] The synthesis of mesocrystals is carried out through a series of chemical reactions to form nanoparticles and self-assembly processes using organic directing agents and bottom-up approaches.…”

Ordered Mesoporous Thin Film Ferroelectrics of Biaxially Textured Lead Zirconate Titanate (PZT) by Chemical Solution Deposition

“…Instead, it seems more likely that the scattering maxima can be associated with the formation of a distorted (111)-oriented face-centered cubic mesophase. [47][48][49] Both of these structures are common in KLE-templated inorganics. [50][51][52] The degree of order is not as high as in other polymer-templated non-silicate thin films 32,34,42,53,54 -the vast majority are binary transition metal oxides -but the material studied in this work is rather complex from a chemical point of view in that three different sol-gel precursors were used in the synthesis.…”