Synthesis of an α-lipoic acid/poly (acrylic acid) based self-healing polymer for potential medical surface-protection applications

Mechanical damage can promote corrosion and microbial accumulation on medical-contact surfaces, while self-healing polymers restore surface integrity and functional performance. In this study, a multi-dynamic self-healing polymer was developed by combining an independently synthesized α-lipoic-acid-based polymer with poly (acrylic acid) Polymer. Characteristic absorption bands at 3400–3200, 1710, 1630, 1540, and 620 cm⁻¹ supported formation of the blended network. The polymer exhibited consistent surface wettability, with water contact angles ranging from 69.2° to 72.0°, together with a glass-transition temperature of − 128.49 °C and a melting transition at approximately 125 °C. Progressive repair occurred at room temperature, reaching approximately 50%, 70%, and 95% crack closure after 6, 12, and 18 h, respectively. The as-prepared polymer showed a tensile strength of 0.98 MPa and an elongation at break of 898%, while the 18 h healed specimen retained a tensile strength of 0.79 MPa and an elongation of 760%, representing approximately 81% tensile-strength recovery. Scratching increased the corrosion rate of polymer-covered mild steel from 0.164 to 3.276 mm year⁻¹, whereas healing for 18 h reduced it to 1.162 mm year⁻¹. Inhibition zones of 22.4 mm against Staphylococcus aureus and 11.2 mm against Escherichia coli further demonstrated antimicrobial activity. Collectively, these results establish the developed material as a promising self-healing polymer for potential medical surface-protection applications requiring flexibility, room-temperature repair, corrosion-barrier recovery, and antimicrobial performance.