Magnetochromatic Microcapsule Arrays for Displays

• Published in: Advanced functional materials 2011-06, Vol.21 (11), p.2043-2048
• Main Authors: Zhu, Cun, Xu, Wenyu, Chen, Liangshui, Zhang, Wendong, Xu, Hua, Gu, Zhong-Ze
• Format: Article
• Language: English
• Subjects: Arrays; colloidal crystal; Displays; Droplets; Magnetic fields; magnetochromatic materials; microcapsules; Microfluidics; monodisperse nanospheres; Nanospheres; Shells; Viewing
• ISSN: 1616-301X; 1616-3028; 1616-3028
• DOI: 10.1002/adfm.201002296

An approach to construct displays based on magnetochromatic microcapsules with narrow size distribution has been proposed. These magnetochromatic microcapsules are fabricated by a microfluidic technology. The shell layer of the obtained microcapsule is composed of transparent photocurable ethoxylated trimethylolpropane triacrylate (ETPTA) resin while the core is formed by the aqueous droplet containing monodisperse magnetic nanospheres. The capsule size, shell thickness, and morphology can be easily controlled by the flow rates during the fabrication. In the multipixel array formed by these microcapsules, each microcapsule acts as an individual display unit. The nanospheres in the core droplet can be influenced by an external magnetic field, forming ordered structures which determine light diffraction; therefore, various distinct colors are observed according to the intensity of the external magnetic field. These microcapsules have the advantage of long time stability, viewing angle independence, and dynamic tunable optics. An approach to construct displays based on magnetochromatic microcapsules has been proposed. A microfluidic technique is developed to control the capsule size, shell thickness, and morphology during the fabrication. When assembled, the microcapsules form multipixel arrays, with each microcapsule acting as an individual display unit whose color can be controlled by an external magnetic field.