Dynamic Cross-Linked Polyurea/Polydopamine Nanocomposites for Photoresponsive Self-Healing and Photoactuation

Designing self-healing materials with multiresponsive self-healing and high mechanical performance has promising applications in wearable electronics and soft robots. In this study, polydopamine (PDA) particles and hindered urea bonds are used as functional nanofillers and dynamic motifs, respectively, in the production of dynamic cross-linked polyurea/PDA (DCPU/PDA) nanocomposites via facile in situ photoinitiated copolymerization. PDA particles form good interfacial bonds with the DCPU matrix, which endows the nanocomposites with enhanced thermomechanical and remotely photoresponsive self-healing properties as well as excellent photothermal effects. DCPU/PDA nanocomposites have higher toughness (∼14.96 ± 2 MJ m–3) and stretchability (up to 334 ± 20%) than pure DCPU. When damaged, they self-heal rapidly and effectively in response to near-infrared light. The fast responsive self-healing ability is enabled by the excellent photothermal effect of PDA and the dynamic exchange reaction of the hindered urea bonds. In addition, DCPU/PDA nanocomposites are malleable and easily recyclable. Finally, their outstanding photoactuation makes them suitable for applications as soft actuators in wearable electronics and soft robots.