Aided Self‐Assembly of Porphyrin Nanoaggregates into Ring‐Shaped Architectures

Abstract

The formation of micrometer-sized, highly ordered porphyrin rings on surfaces has been investigated. The porphyrin-based nanoarchitectures are formed by deposition from evaporating solutions through a surface dewetting process which can be tuned by variations in the substitution pattern of the molecules used, the coating of the surface and the conditions under which the evaporation takes place. Control over the combined self-assembly and surface dewetting results in nanorings possessing a defined internal architecture. The ordering of the molecules within the rings has been studied by a variety of microscopy techniques (TEM, AFM, fluorescence microscopy) and the exact ordering of the porphyrins within the rings has been quantified.

Nanorings and rods interconnected by self-assembly mimicking an artificial network of neurons

“…It is important to mention here that the spontaneous formation of rings by self-assembly has been scarcely reported. Most of the reported structures follow formation mechanisms derived from de-wetting processes in which either the spontaneous formation of pinholes, 2D bubbles, the concentric accumulation of material mediated by local capillarity (coffee-stain effect) or Marangoni-flow engineering produce rings on flat surfaces [38][39][40][41][42][43][44] . However, none of the latter mechanisms can explain the formation of the rings for derivatives 4 that are interconnected in a neural network fashion both on flat surfaces and inside a polymeric matrix.…”

Supramolecularly Engineered Functional π-Assemblies Based on Complementary Hydrogen-Bonding Interactions

“…More importantly, the formation of the self-assembled catenanes corroborates that nanorings are already formed in solution phase, and not the product formed via evaporation of solution. 67 Compound 26 afforded a larger number of nanorings with diameters of ca. 25 nm even when the sample was prepared from a 1 © 10 ¹3 M solution (Figure 25f ).…”

Ring and Volcano Structures Formed by a Metal Dipyrromethene Complex

“…Previously fluorescence images of the ring structures formed from porphyrins were collected to understand the structures of the central areas. 14,15 In the present work LFM imaging was used to characterize the presence of molecules in the central region. LFM measures the friction characteristics of a surface and is useful for characterizing the composition of a surface layer because the measured friction constant will depend on the material.…”

“…The evaporation of a liquid droplet to produce a film containing porphyrin derivatives on a solid substrate produces a variety of nano-and meso-scale structures, including rings, [10][11][12]14,15 volcanos, 12 disks, 16,17 and rods. 18 Although a general understanding of the mechanisms underlying the formation of these structures has yet to be elucidated, it appears that the initial driving force underlying the formation process is provided by the complex interplay between the solvent, substrate, concentration, or evaporation environment.…”