Bioinspired Adaptive Microplate Arrays for Magnetically Tuned Optics

In this work, magnetic field driven polymer microplate arrays are fabricated to modulate the optical properties of the sample, i.e. reflectance and fluorescence. Inspired by poplar leaves, which rotate the high reflectance white side of the leave upwards to act as a “roof” under strong light radiation, and switch the low reflectance green side for photosynthesis back again when the light is less severe. In this study, gold was selectively deposited on one side of the microplate, and surface reflectivity can be reversibly switched from higher to lower state through the change of the magnetic field direction to bend the microplates with the gold side facing up and down. The modulation of fluorescence emission is realized by magnetically control the tilting angle of the microplates, in the same way as a venetian blind. The fluorescence intensity reaches its maximum and minimum at the perpendicular and parallel position to the fluorescent substrate, respectively. This system provides a fast responding and remote controllable means to modulate the optical properties of samples, which has been considered important in certain applications, such as smart reflectors, environmentally friendly windows, and field emission.