Uniform Mesoporous Silica Hexagon and Its Two‐Dimensional Colloidal Crystal

Well‐ordered mesoporous silica nanoparticles with uniform hexagonal disk shapes are synthesized under dilute alkaline conditions with a two‐step process, separating the nucleation and growth process. The resulting monodisperse hexagons can be arranged in a 2‐dimensional (2D) ordered periodical super‐structure. The hexagonal symmetry is similar in both scales. A statistical mechanical cell model is applied to analyze consequences of the interesting packing structure, including osmotic bulk modulus, phase separation and defects.