Fig. 3: Self-assembly of MIL-88A particles.
From: Low-dimensional assemblies of metal-organic framework particles and mutually coordinated anisotropy
a–d 1D top-down alternating chain of MIL-88A particles formed on a smooth substrate. a Cartoon (left) shows the particle orients its (100) face towards the substrate by depletion attraction. Cartoon (right) shows the particles in the upper layer (light brick red) bind with those at the bottom (dark brick red) by the side faces (purple, n = 2). b Optical image of MIL-88A chains. Inset is the zoomed-in optical and reflected-light confocal image of the chains, both showing an alternating pattern. Optical images and cartoon in (c) show a microscope focus series of the chain. Snapshots from a movie (d) show the chain formation process. e–h 2D snowflake-like network of MIL-88A particles, formed on a rough substrate (gray plate with yellow dots). Schematic in (e) shows two short chains bind via (100) faces to form a branch, which flips over and stands on the substrate by their pyramidal tips ([001] direction). Cartoons in (f) compare the fully coordinated structure (n = 6, left) with the actual unsaturated network structure (n ≤ 6, right). Optical images in (g) show the flipping and branching process. Optical image in (h) shows the snowflake-like networks and the angles of branch junctions (inset). Scale bars: 5 and 1 μm (inset) for (b), 1 μm for (c, d), 2 μm for (g), 5 and 2 μm (inset) for (h).
