Anti-reflective biomimetic nanostructures formed by 2D arrays of silica colloidal particles via self-assembly using sublimation, polymer solidification, and thermal fusion

Abstract Nano-size protrusions have attracted significant interest in biomimetic applications, such as mechanical engineering, optics, and biosciences. One of the most effective methods for fabricating such nanostructures is the use of two-dimensional (2D) self-assembly of colloidal particles. Herein, three types of novel self-assembly approaches for synthesizing homogenous 2D colloid arrays using sublimation, polymer solidification, and thermal fusion are presented. In the first approach, the sublimation method was applied by coating silica colloids and sublimable compounds on a substrate, followed by exposing them via sublimation. In the second one, polymer solidification method was developed by using the colloids, polymers, and fluorinated solvents with high boiling points, followed by evaporation of the solvents. Final approach involved forming 2D arrays of silica-polymer core-shell nanoparticles using layer-by-layer techniques and the subsequent thermal fusion of polymer shells on the particles. Homogenous nano-protrusions were obtained using these three methods. In addition to these uniform arrangement methods, application of colloid monolayers in moth-eye-type anti-reflection films were confirmed. These bottom-up technologies are expected to contribute to multifaceted applications and high-throughput techniques for fabricating nanostructures.