Three-Dimensional Printing of Liquid Crystals with Thermal Sensing Capability via Multimaterial Vat Photopolymerization

Creatures in nature possess unique smart material systems that can sense environmental changes with evolved self-responsible architectures. For example, the Japetella heathi octopus exhibits a remarkable ability to change its appearance to evade the attention of predators. Here, we present an approach to produce Japetella heathi-inspired smart materials with thermal sensing architectures by multimaterial three-dimensional (3D) printing, where both conventional acrylic-based ultraviolet resins and reactive liquid crystals (LCs) are photocured to form an object with desired patterns. The levels of orientational and positional orders of LCs in unique thermodynamic phases (e.g., nematic and isotropic phases) can be modulated by the local temperature of the material. As a result, the 3D printed liquid crystalline materials (within the printed multimaterial object) possess a unique optical property that can reversibly transition from opaque (in the nematic phase) to transparent (in the isotropic phase) in response to external thermal stimuli. The multimaterial 3D printing process provides a versatile manufacturing tool that enables the design and fabrication of bioinspired smart materials with complex 3D shapes for various potential applications, such as soft robots, flexible sensors, and smart anticounterfeiting devices.