Photoresponsive Cyanated Azopolymers With Enhanced Identifiability of Photopatterned and Nanoimprinted Structures for Orthogonal Dual‐Mode Encryption

ABSTRACT Photoresponsive azopolymers can construct dual‐mode encryption patterns with high security. Cyanated azopolymers offer superior pattern identifiability due to the large dipole moment of cyano groups, which enhances photoinduced orientation of azobenzene units. However, the controlled synthesis of cyanated azopolymers remains challenging because cyano groups inhibit several types of polymerizations. Herein, we report controlled synthesis of a cyanated azopolymer via a modified ring‐opening metathesis polymerization (ROMP) method and use it to construct dual‐mode encryption patterns. The cyanated azopolymer exhibited photoswitchable glass transition temperatures ( T g s) and photoinduced orientation, which enabled the fabrication of orthogonal dual‐mode patterns by the combination of nanoimprint lithography and photopatterning. Compared with a non‐cyanated azopolymer, the cyanated azopolymer can create dual‐mode encryption patterns with enhanced identifiability. This work offers a new strategy to overcome the synthetic challenges for functional cyanated polymers and demonstrates that cyanated azopolymers provide a novel platform for designing high‐security encryption patterns with enhanced identifiability.