Structural Coloration with Nonclose‐Packed Array of Bidisperse Colloidal Particles. Issue 5 (13th January 2019)

• Record Type: Journal Article
• Authors: Lee, Gun Ho; Kim, Jong Bin; Choi, Tae Min; Lee, Jung Min; Kim, Shin‐Hyun
• Is Part Of: Small. Volume 15:Issue 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-01-13
• Subjects: colloidal arrays -- colloids -- mechanochromism -- repulsive potential -- structural colors; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201804548
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Colloidal crystals and glasses have their own photonic effects. Colloidal crystals show high reflectivity at narrowband, whereas colloidal glasses show low reflectivity at broadband. To compromise the opposite optical properties, a simple means is suggested to control the colloidal arrangement between crystal and glass by employing two different sizes of silica particles with repulsive interparticle potential. Monodisperse silica particles with repulsive potential spontaneously form crystalline structure at volume fraction far below 0.74. When two different sizes of silica particles coexist, the arrangement of silica particles is significantly influenced by two parameters: size contrast and mixing ratio. When the size contrast is small, a long‐range order is partially conserved in the entire mixing ratio, resulting in a pronounced reflectance peak and brilliant structural color. When the size contrast is large, the long‐range order is rapidly reduced along with mixing ratio. Nevertheless, a short‐range order survives, which causes low reflectivity at a broad wavelength, developing faint structural colors. These findings offer an insight into controlling the colloidal arrangements and provide a simple way to tune the optical property of colloidal arrays for structural coloration. Abstract : A colloidal arrangement is systematically controlled between crystal and glass by employing two different sizes of repulsive colloidal particles. The degree of ordering is finely adjusted by controlling size contrast and mixing ratio, which enables the manipulation of the shape of the reflectance spectrum. This simple yet highly controllable approach is useful for tuning the optical property of colloidal arrays for structural coloration.