High‐Resolution Erasable “Live” Patterns Based on Controllable Ink Diffusion on the 3D Blue‐Phase Liquid Crystal Networks

Colorful blue phase liquid crystal (BPLC) patterns have attracted wide research attention owing to their intriguing and advantageous properties and promising applications. However, it remains a challenge to develop novel and high-resolution patterns from BPLC owing to the complicated synthetic procedure for the functional molecules. This study reports a high-resolution "live" pattern by well-designed diffusion of 5CB ink on the wettability-modified BPLC networks. Interestingly, the shape and color of the as-prepared pattern change with time, which results in unique spectra change of the printed pattern, "first red-shift and subsequent blue-shift of the stopband position" and "continuous growth in reflectivity intensity" with time. The hydrophobic substrate greatly suppresses the random spreading and diffusion of ink, contributing to high-resolution patterns. The promising applications of live patterns for program display and active labels are demonstrated. Various high-resolution erasable colorful patterns are obtained. The structure reconfiguration of the writing and erasing processes is proved by transmitted electronic microscope images and Kossel diffraction diagrams, which ensures the reversible writing/erasing of the pattern on the membrane. This work is of significance for the development of novel rewritable paper and high-quality optic devices based on BPLC materials.