Fig. 3. FCLC microdroplets fabricated by capillary microfluidic technique.

a Schematic illustration to show the capillary microfluidic device used to fabricate the FCLC microdroplets. The hydrophobic and hydrophilic surfaces of the capillaries are denoted in red and blue. The 5 wt% PVA aqueous solution is used as continuous phase to facilitate planar alignment of the LC molecules and radial alignment of the helical axes. b Normalized reflectance spectra of the FCLC microdroplets containing 6, 5, 4, 3 wt% chiral dopants, respectively. c–f Photographs of blue, green, red, and infrared FCLC microdroplets to show striking reflection colors under white light and fluorescent color upon UV irradiation. g–j POM images of blue, green, red, and infrared monodisperse FCLC microdroplets in hexagonally close-packed arrays to show photonic cross-communication and fluorescent patterns. Additional lines caused by double reflection are denoted by white arrows. The scale bar is 100 μm.