Scalable Photonic Liquid Crystal Nanoscale-Thick Films for Deformation and Discoloration

A self-assembled three-dimensional (3D) nanomaterial, blue phase liquid crystal (BPLC), with elastic deformation is the aim of a stimuli-responsive material because it combines the 3D photonic nanostructure and the rubber elasticity of the elastomer network. However, there is still a lack of a flexible approach to preparing BPLC films with high elastic deformation and a low glass-transition temperature. Here, we develop a reproducible and scalable two-step protocol of the thiol-acrylate Michael addition (TAMA)–photopolymerization reaction approach for the preparation of high-performance, low glass-transition temperature, and uniform BPLC films. Linear chain extension occurs through the TAMA reaction, and the cross-link density and molecular weight can be programed by varying the reaction time, resulting in the phase transition from blue phase I to the chiral nematic phase. The cross-linking density, molecular weight, and resulting structure can be frozen by forming an elastic network using photopolymerization. The results show that the increase of elastic deformation by 3 times, shift of the structural color >186 nm, and lowering of the glass-transition temperature to −34.93 °C are successfully achieved. In addition, the BPLC film pattern can sustain repeatable, rapid, and continuous elastic deformation and a uniform structural color change when triggered by multiple stimuli of temperature, stretching, and organic vapor. This work provides new insights into customizable stimuli-responsive 3D photonic nanostructured materials, facilitating their application in sensing, display, and anti-counterfeiting.