Preparation of 4D hydrogels with PET-RAFT and orthogonal photo-reactions†

We conducted an experiment to compare the predicted outcomes with the practical results of synthesizing four-dimensional (4D) hydrogels and observing their 4D motion. We employed a computer simulator and utilized PET-RAFT and orthogonal chemistry methods. To initiate the study on 4D materials, we employed the swelling method and controlled it by utilizing visible light synthesis. To regulate the irradiation time of blue light, we employed cinnamoyl ethyl acrylate as an orthogonal system to control crosslinking density. Various physical properties were assessed using a rheometer. Our findings confirmed that the movement could be controlled by adjusting the swelling ratio of the upper and lower parts, thereby implementing a bi-layer design based on differences in crosslinking density. This study highlights the successful synthesis of hydrogels with diverse physical properties and demonstrates the potential of 4D materials through the orthogonal synthesis technique.