Colloidal Surface Assemblies: Nanotechnology Meets Bioinspiration

Abstract

This Feature Article discusses two biomimetic aspects of functional particle surface assembly: the fabrication of biologically inspired structures from particles and the arrangement of particles on biomimetic templates. The fi rst part discusses the creation of primary patterns by convective assembly and adsorption of particles that can be modifi ed by a combination of etching and growth steps. Resulting structures mimic moth eyes, Lotus leaves, and the Gecko's adhesive structures, for example. The second part focusses on template assisted self-assembly (TASA) of particles. Herein, biological examples are inspiring in terms of structure formation related processes, rather than in terms of functionality. Template formation is a major bottleneck TASA. It is illustrated how bio-inspired wrinkling processes help overcoming this problem and can be employed for forming highly ordered functional nanoparticle assemblies.

Ultra-high ordered, centimeter scale preparation of microsphere Langmuir films

“…3 is a detailed view of Fig. 2, revealing the domains in the monolayer; observation of domains has also been reported elsewhere [20][21][22][23]32]. When a monolayer is compressed, it undergoes through several phases, and the appearance of domains occurs in liquid expanded (LE) -liquid condensed (LC) transition [33].…”

“…By transferring monolayers of various compounds/materials from a liquid to a solid substrate, the structure of the film can be controlled at the molecules/particles level [3][4][5]. Methods to generate and/or deposit self-assembled monolayers of hexagonally close-packed (HCP) of micro-and nanospheres include spin coating, dip coating, drop casting, thermoelectrically cooled angle coating, electrophoretic deposition, assembly at air/liquid and liquid/liquid interface, convective assembly, and even laser-induced forward transfer (LIFT) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Such deposition methods require that spheres can diffuse freely across the substrates, seeking their lowest energy configuration.…”

A colloidoscope of colloid-based porous materials and their uses

“…52,117 Colloidal monolayers can be especially valuable as templates or masks for etching or evaporation processes to create functional surface nanostructures or coatings. There have been intense research activities in the last decade on the generation of arrays of nanostructures using colloidal monolayers, as discussed in several recent review articles; [117][118][119][120] here, we only introduce general strategies and highlight a few examples in Figure 4A.…”

Bioinspired 1D Superparamagnetic Magnetite Arrays with Magnetic Field Perception

“…Compared to the topdown techniques, bottom-up assembly methods, such as inkjet printing, soft lithography, and nanoimprinting, possess many advantages of high efficiency, low cost, and large-scale processability. [21][22][23][24] Yet owing to the uncontrollable dewetting process of liquid in these methods, the fabricated micro-/nanostructures often display disordered particle stacking and high-density defects, inducing the deteriorated performance of assemblies.To assemble nanoparticles into 1D arrays, herein, we propose and experimentally demonstrate a bottom-up liquid-processing method, termed capillary-bridge-mediated assembly (CBMA), allowing the fission of continuous aqueous thin-film dispersion of magnetite and formation of individual microscaled capillary bridges with 1D configuration and high aspect ratio. With the evaporation of water, the stacking of magnetite nanoparticles generates severalmillimeters long, submicrometer wide wires with ultrahigh aspect ratio >5000, strict alignment and precise position.…”