2D and 3D Printable Self-Healing Hydrogels Based on Polyacrylic and Tricarballylic Acids through a Double Network Strategy

Mechanical and self-healing properties are desirable characteristics for engineering hydrogels for various practical applications. However, developing hydrogels that combine these attractive properties in a single material remains challenging. This work attempts to address this issue by designing and synthesizing a metallohydrogel using a double network (DN) strategy. The gel, composed of poly(acrylic acid), tricarballylic acid (TA), and Fe3+, exhibits excellent mechanical strength (with a tensile strain of 3145% and tensile stress of 51 kPa) and high self-healing properties (with a HE of 93%) under ambient conditions without any external trigger. The modified hydrogel enables 3D printing structures, paving the way for future applications in diverse fields, ranging from soft robotics to energy storage. Furthermore, the required rheological properties, such as non-Newtonian and shear thinning behavior, are achieved for the ink by optimization of the composite concentration. More importantly, the prepared ink is able to print different structures with a high degree of accuracy.