Vertically aligned and non‐close‐packed arrays of dumbbell‐ and bullet‐shaped nanoparticles fabricated via self‐assembly

Biomimetic nanostructures are attracting great interest because of their applications in mechanical engineering, optics, and biosciences. One of the most effective methods for fabricating nanostructures is forming particle arrays that have controlled shapes and placements. Herein, a novel self‐assembly method for forming vertically aligned arrays of anisotropic‐shaped particles is described. The particles can be vertically aligned with controlled spacing on substrates using a layer‐by‐layer method and thermal fusion. This method can be applied to particles of various shapes; for example, dumbbell‐shaped particles with an aspect ratio in the range of 1.2–1.9 and bullet‐shaped particles with an aspect ratio of two or more are aligned on substrates. From the results of the simulation of particle arrangement, the particles are oriented in the layer‐by‐layer process if they have anisotropy in terms of the shape, specific gravity, and surface charge of the particles. Furthermore, to make the particles stand upright, it is necessary to heat the particles at a temperature equal to or higher than the glass transition temperature of the polymer that covers the particles. This method is applicable to form broadband high aspect nanostructures, and the vertically aligned particle array shows good anti‐reflection properties and high transparency. A self‐assembly method for forming vertically aligned and non‐close‐packed arrays of anisotropic‐shaped nanoparticles via a layer‐by‐layer method and thermal fusion is described. This method applies to various particle shapes and sizes, and broadband high aspect nanostructures can be formed. This cost‐effective nanostructure fabrication method is applicable to moth‐eye‐type anti‐reflention films, and they shows good antireflection properties and high transparency.