Rapid Synthesis of Self-Healing, pH-Responsive IA-Based Hydrogels via Frontal Polymerization

Self-healing polymeric gels have emerged as a promising class of materials due to their ability to repair damage autonomously, offering significant advantages for various applications. Nevertheless, a major hurdle to their widespread practical use lies in their often-compromised mechanical strength and long reaction time. Herein, we present the synthesis of a new type of self-healing hydrogels using poly(itaconic acid-co-hydroxypropyl alcohol-co-acrylic acid), also known as poly(IA-co-HPA-co-AAc), by a frontal polymerization (FP) method. The rapid reaction rate of FP facilitates the swift and energy-efficient synthesis of the hydrogels within 10 min, eliminating the need for prolonged reaction times. Additionally, the results revealed that the synthesized hydrogels exhibited pH-dependent responsiveness, robust mechanical integrity, and autonomous self-healing capabilities, obviating the requirement for external stimuli. The exceptional self-healing properties can be attributed to the extensive hydrogen bonding network between the polymer chains, enabling them to recover up to 80% of their original mechanical strength. Rheological analysis confirmed the presence of a robust and stable gel network, evidenced by high storage modulus (G′) values across the entire frequency and strain sweep tests. This research addresses a significant knowledge gap in IA-based hydrogels by introducing a rapid, optimized method for constructing self-healing materials through hydrogen bonding interactions.