Multicolor Printing Using Electric-Field-Responsive and Photocurable Photonic Crystals

Efficient and large scale printing of photonic crystal patterns with multicolor, multigrayscale, and fine resolution is highly desired due to its application in smart prints, sensors, and photonic devices. Here, an electric-field-assisted multicolor printing is reported based on electrically responsive and photocurable colloidal photonic crystal, which is prepared by supersaturation-induced self-assembly of SiO₂ particles in the mixture of propylene carbonate (PC) and trimethylolpropane ethoxylate triacrylate (ETPTA). This colloidal crystal suspension, named as E-ink, has tunable structural color, controllable grayscale, and instantly fixable characteristics at the same time because the SiO₂/ETPTA-PC photonic crystal has metastable and reversible assembly as well as polymerizable features. Lithographical printing with photomask and maskless pixel printing techniques are developed respectively to efficiently prepare multicolor and high-resolution photonic patterns using a single-component E-ink.