Visualization of real-time film formation process and its dynamic behavior in 4D printing

Understanding the real-time film formation process and dynamic behavior of soft materials is essential for optimizing 4D-printed structures with precise morphing capabilities. To address this, we developed a photocuring material by strategically incorporating vibration-induced emission molecules. Leveraging the unique saddle-shaped architecture, multicolor fluorescence properties vividly appeared during the whole photocuring process. Specifically, each fluorescent color represented different film formations of distinct degrees of polymerization. The resulting films demonstrate tunable rigidity and remarkable solvent-responsive dynamic behavior. At the same time, their luminescence transitions during deformation provide direct visual feedback, enabling real-time monitoring of 4D printing transformations. This innovative approach not only offers unprecedented insight into structural evolution but also paves the way for multifunctional devices with seamlessly integrated luminescence properties.