Magnetic field responsive microspheres with tunable structural colors by controlled assembly of nanoparticles

• Published in: RSC advances Vol. 12; no. 9; pp. 5656 - 5664
• Main Authors: Shang, Shenglong, Zhang, Kaiqi, Hu, Huifang, Sun, Xiaoran, Liu, Jie, Ni, Yanpeng, Zhu, Ping
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 10.02.2022; The Royal Society of Chemistry
• Subjects: Camouflage; Chemistry; Color; Flow velocity; Iron oxides; Magnetic fields; Microfluidics; Microspheres; Nanoparticles; Ultraviolet radiation
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d1ra09028c

Dynamic color tuning has many useful applications in nature for communication, camouflage, mood indication, etc. Structural colors have more advanced applications due to their ability to respond to external stimuli by dynamically changing color. In this work, we proposed an efficient method to prepare magneto-chromatic microspheres with tunable structural color. Through a microfluidic technique, the magneto-chromatic microspheres containing Fe 3 O 4 @C magnetic particles were continuously prepared. The size of the microspheres decreases with the increase of PVA solution phase to ETPTA phase flow rate ratio. Furthermore, the microspheres with larger sizes more easily form close packed structures. Microspheres can be constrained in PVA to form a free-standing film after the evaporation of water in PVA solution. The PVA film could display tunable brilliant structural colors when an external magnetic field is applied. Moreover, microspheres with fixed structural colors can also be acquired by polymerizing microspheres under UV light under an external magnetic field. An efficient strategy was used for the preparation of magneto-chromatic microspheres with tunable structural color.