Squid-Inspired Smart Window by Movement of Magnetic Nanoparticles in Asymmetric Confinement

The camouflage used by cephalopods is an interesting topic in biomimetics. Squid, part of the cephalopod family, have transformable skin that can be made transparent or darkened through control of the light-absorption area. This is achieved using a muscular structure. A smart-window scheme inspired by this is developed. Magnetic nanopigments dispersed within an asymmetric pyramidal array are used and the light-absorption area is manipulated through use of a magnetic field. Refractive-index-matched liquids are used as a dispersion media to avoid refraction at the interface. The transparency hysteresis (ON/OFF ratio) performance depends on the ratio of magnetic nanoparticles and the dispersive fluid and a model is derived to explain this. In addition, a 3D-printed structure is proposed and demonstrated for better performance.